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Handbook of bird biology


Material Information

Handbook of bird biology
Title on t.p. verso:
Cornell Lab of Ornithology's Handbook of bird biology
Portion of title:
Bird biology
Alternate Title:
Cornell Lab of Ornithology's Handbook of bird biology
Physical Description:
1 v. (various pagings) : ill. (some col.), maps (some col.) ; 29 cm. +
Bonney, Rick, 1954-
Rohrbaugh, Ronald W
Podulka, Sandy
Cornell University -- Macaulay Library of Natural Sounds
Cornell University -- Laboratory of Ornithology
Cornell Lab of Ornithology in association with Princeton University Press
Place of Publication:
Ithaca, N.Y
Publication Date:
2nd ed.


Subjects / Keywords:
Bird watching -- Handbooks, manuals, etc   ( lcsh )
Birds -- Handbooks, manuals, etc   ( lcsh )
Ornithology -- Handbooks, manuals, etc   ( lcsh )
Ornithology -- Textbooks   ( lcsh )
bibliography   ( marcgt )
handbook   ( marcgt )


Includes bibliographical references and index.
Statement of Responsibility:
Sandy Podulka, Ronald W. Rohrbaugh, Jr., and Rick Bonney, editors.
General Note:
Title on accompanying compact disc: Vocal behavior : audio tracks to accompany chapter 7 / produced by the Macaulay Library. Ithaca, NY : Cornell Laboratory of Ornithology, c2000.
General Note:
Compact disc title: Vocal behavior: audio tracks to accompany chapter 7. Cornell Lab of Ornithology, c2000.

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University of South Florida Library
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University of South Florida
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All applicable rights reserved by the source institution and holding location.
Resource Identifier:
aleph - 024903560
oclc - 57003728
lccn - 2004105098
isbn - 093802762X (hbk.)
usfldc doi - S62-00014
usfldc handle - s62.14
lcc - QL673 .H263 2004
ddc - 598
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Handbook of bird biology /
Sandy Podulka, Ronald W. Rohrbaugh, Jr., and Rick Bonney, editors.
1 246
i Title on t.p. verso:
Cornell Lab of Ornithology's Handbook of bird biology
Bird biology
Cornell Lab of Ornithology's Handbook of bird biology
2nd ed.
Ithaca, N.Y. :
Cornell Lab of Ornithology in association with Princeton University Press,
1 v. (various pagings) :
ill. (some col.), maps (some col.) ;
29 cm. +
e 1 sound disc (digital ; 4 3/4 in.)
Title on accompanying compact disc: Vocal behavior : audio tracks to accompany chapter 7 / produced by the Macaulay Library. Ithaca, NY : Cornell Laboratory of Ornithology, c2000.
5 FU
Compact disc title: Vocal behavior: audio tracks to accompany chapter 7. Cornell Lab of Ornithology, c2000.
Includes bibliographical references and index.
Birds and humans : a historical perspective -- Introduction : the world of birds -- A guide to bird watching -- Form and function : the external bird -- What's inside : anatomy and physiology -- Birds on the move : flight and migration -- Evolution of birds and avian flight -- Understanding bird behavior -- Vocal behavior -- Nests, eggs, and young : breeding biology of birds -- Individuals, populations, and communities : the ecology of birds -- Bird conservation.
Bird watching
v Handbooks, manuals, etc.
Handbooks, manuals, etc.
Handbooks, manuals, etc.
Bonney, Rick,
Rohrbaugh, Ronald W.
Podulka, Sandy.
Cornell University.
Macaulay Library of Natural Sounds.
Cornell University.
Laboratory of Ornithology.
t Natural Sciences Collection


Handbook of Bird Second Edition Sandy Podulka, Ronald W Rohrbaugh, Jr., and Rick Bonney Editors Pub I is hed by the Cornell Lab of Ornithology in association with Princeton University Press LAB of ORNITHOLOGY 159 Sapsucker Woods R oad 11haca, New York 14850 USA www. birds .t;:Orn e l l .edu


LAB of ORNITHOLOGY 1 59 Sapsucker Woods Road Ithaca, NY 14850 (607) 254-B IRD (2473) www. bi r ds.corne A membership institution working to inletpret and conserve the earth j> biological diversit)' through research, education, and citizen science focused on birds, The Cornell Lab of Ornithology's Handbook of Bird Biology, Second Edition Pllbilshed it! with Princ&ttm Utliversi(y Press, 41 William Street Princetc>n New jerse y 0854fl ancl, in the United Kingdom, J Market Place Woodstock, Oxfords/lire OX: !O I SY wlvw.natiJist.ptincetoll.edt l Ronald W. Rohrbaugh. Jr., Project Manager Sandy Podulka, Ronal d W. Rohrbaugh, Jr., and Rick Bonney, Editors Marie Read. Photo and l llustratie>n Editor N. John Schmitt. I llustr ator 01,1ne L. Tessagl ia-H ymes, Graph i c Designer tditor1aiASststan<.:e: Daniel R. Otis, Marie Eckhardt, ) B. Heiser andlenyMing l e Design Assistahce: Palt y Porupski Kathy Terry M ingl e and Richanna Patrick Chr is t i Sobel CD Narrator: Margaret A Barker Acknowledgments Inaddi t ion to the authors and other major contributors, we thank the to/lowing fndMdu11/s for !heir help with the enormous ta sk uf completing this Ken Abl e O;!rl D. Barrantine Lr>uis B Best, John Bower Jack Brncl hury, Greg Budney, Russ Cllarii, Natal i e Demong, Kanneth P. Di al, Tim Dillon Robert). Dooling, Lang Elliott Steve Em len, 13fll Evans, J ohn Fitzpatrick, Adam Frankel, Kurt FrlstruJ,, Melissa Fowler, Tim Gallagher, 1 -tarry W. G r eene.lo h n Greenly, Bob Grotke Michae l I. Hamas. Mark E Hauber lohn HermJnson, leslie Intemann, Paul Kerlinger. George Kloppel Stephen W. Kress, Kroodsma. Kevin McGowan. jason Mobley, frank K. Moore. Eugene S. Morton Drew M. Nouen, Stephen Nowi c ki Steve Pantie. Irene Pepperberg, l:lill Podulka, Suzan n Regetz, Ken Rnsenberg. Karel A. Schat, Roger Slothower, Laura Stenzler, Peter SLeltenheim, SandrA Vehrencamp, Peter Wlege Cove r P/Jotograp/1s Front left to righr; Whooping Crane preening by Arthur Morris/Bird s Art ; AmeriC

Preface Welcome t o the second edition of the Cornell Lab of Ornithology's H a ndbook of B ird Biology! Some readers may recognize the content of this book as the backbone for the second edition of the lab's popular and long running Home Study Course in Bird Biology. While this book wil l co ntinu e to satisfy that thanks to the modified format and an in novative partnership with Prin ceto n University P ress, it will a lso serve. as the most useful general ornitho l ogy reference cu rrentl y avai l able. The continued expansion of ornithology as a premier scientific discipline and the rapid growth of bird watching as a recreational pastime indicate that the need for a modern top-quality textbook and dist ancelearning course in orn ith ology n ever has been greater. Th e Cornell Lab of Ornithology is proud to be filling this ni c he. Our Home Study Course originally was conceived to provide comprehensive, college-level information on birds and their environments in a manner accessible to nonscientists and teachers the world over, and we hope that this book will be useful to everyo n e with an interest in birds Th e H c1ndbookof8ird Biology and the Home Study Course b uild upon the highly successfu l first edition re l eased in 1972, edited by well-known ornithologist and former dire ctor of the Cornell lab of Ornithology, Olin Sewall Pettingill, Jr. Dr. Pettingill's groundbreaking course included ("line "seminars," each foc used on a different ornithological subject, and eac h was followed by iln exam that st udents completed and r eturned to the L ab for grad ing From 1972 to 1998, more than 1 0 ,000 students completed the course, a testament to its popularity and to Pettingill's skills as a writer, editor, and teac her.


ii Thr ougho ut the 1970s and '80s the course underwent several revi sions to refled new findings in ornitho logy and related disciplines. B y the mid-1990s, however minor revisions no longer wer e suffic ient to reflect new and relevant ornitho l ogical finding s i n v ibr a nt research areas such as animal communication, conservation biology, a n imal behavior, and evo lutionary biology. Therefore, in 1998 the Lab of Ornithology temporarily stopped enroll in g new students in the Hom e Study Course so that science education staff at the Lab co uld beg1n the chall enge of overhauling the course from top to bottom and expand t n g its coverage by e ngaging som e of the most knowledgeab l e professional ornithologists to bring the Home Study Course into the modern era of ornithology The second edit i o n contains new text, photographs, illustrations, graphs, and tables. It covers a ll of the major topics addressed in the first e d i tion, from anatom y and physiology to ecology a nd behavior. In add i lion we've added a comple t e chapter on bird id entif i cation and anoth er o n conservation to make it more useful for birders a nd to introduce the relatively new science of conservation bio logy. We've a lso added a chap ter on vocal communi cation, whic h in k eeping W ith the Lab's tradit ion of recording a n d producing m e di a u s in g high-quality a nim a l sounds f or e ducation and research, is accompanied by an audi o CD of bird vocaliza tions that are used to illustrat e the many ele m e nt s of b ioacoustics. We a r e confident that you wil I f i nd the Handbook of Bird Biolog y to be an essential r esource fo r all of you r bird-re l a ted questions. Home S tudt1 Course and of Completion I n addition to serving as a general ornitho logy reference, this book is meant t o accompany the Home Study Course in Bird Biology (HSC) administered by the Lab of Ornithology Education staff. To s uccessfull y comp lete the course you must read each chapter at your own pace and comp lete an open-boo k exam ( paper o r onl ine) for each o f the 10 c hapters. Exams a r e graded and returned so that students can r eview their a nswer s and keep track of their p erfor m a nce. Questions and co m ments can b e s ubmitted to the course instructor, w ho will hel p guide stud ents through the most challeng l n g material. After comp le tin g a ll 1 0 chapters and exam s w ith passing grades, you w i ll receive a cert ifi cate of compl et ion signed by the Louis Agassiz Fuertes Director of the Lab of Ornithology. We are constantly working to incorporate n ew informa tion, suppl e mental materials, and d istance l earning t oo l s on our website to keep t h e HSC content current, provide additiona l resources, a nd cre ate an environmennh at w ill keep students engaged and motivate them throug h comp l etion a nd certifi cation. Please visit our web site for the latest HSC information. To e nr oll call u s at 800-843-BIRD ( o utside the U nited States a t 607-254-2452), sign up on our web site, or mail the card inserted i nto thi s book. Whether you acqui red the Handbook of Bir d Biolog y to use as a general ornitho l ogy reference or r eceived it as a part of your enrol l ment in the Home Study Course, we wish yo u the very besL in your quest f o r more k n owledge and awar eness about the many int eresting facet s that characterize the science o{ ornithology We h ope that this book provides yo u with an accessible gat eway to the information you seek, and that it func t io n s as a top-notch reference fo r year s t o come. --Com ell Laburaton1 of Omitfwlo[jtl


Table of Contents BtR.D S AND HUMANs: A H tsrOR.ICAL P ERSPECTIVE Bird s as F oo d ... .. .... .......... ..... ........ ......................... ............... H 3 Use of Skins and ....................................... ................. H 4 Bird s in Literature Culture and Religion .................................. H 6 Art .................. . ............. ..................................... ............... H Religion . .......... ............ . .. .... ..... ........................................ H Fol k l ore .................................................. .............. ............ H l 0 Literature .................................................. .. .. .................... H Music a nd D a n ce ............................................................. H Music a n d D ance of I ndigenous C ul tures ................ .. ... H 13 Music a nd Dance of Western Cu l tures .................. ...... H The E volutio n of North American Ornithology ....................... H Th e E a rl y Years: F rom A ri stot l e to the 17th Cent ur y ......... ... H The 18th Cent ur y .......... .................................................... l-123 The 19th Ce ntur y ............................ ..... ............................. H TI1e American Ornithologists' Union and the U.S. Biological Survey ............................................ H32 The First Audubon Movement ................ ..................... H 33 The Second Audubon Movement.. .... .... ..... ................. H The 20t h Century and the Expanding Role o( the Bird Watcher ...................... ............. ...... .............. H The Developme n t of the Field Guide .......... ................. H Acade mi c Traini n g in Orni thology ............................... H37 Bird Co n servation, Bird Watch ing, and the Age ofTechnol ogy ........... .. .......................... H S uggest e d Reading s ........................................................ ........ H


iv CHAPTER 1 I NTR.ODUcrloN: THE WoRLD OF BIRDS Ornithological Terms .............. ... ................................................ 1 The Form of a Bird -1 Bill ....................................................................... ... ....... ..... 1 6 Head and Neck ........ .................... .... ........... .. ...................... 1 Trunk ..... .... .... ... .... .... . ....... . ... ........ ......... ........ ... .............. 1 Wings ......... .. ............ .......... . ........... ... . .... ... ... .... ............... 1 Tail ..... .... .... ..... .. ........... ... ..................... ... .. ... .. ... .. .... . .. .... 1 12 Hind Limb s . ...... ........ ....... ....... ... ..... ......... ........ ...... ......... 1 12 Diversity in Bird Form ...... .. ........... .... ...... ....... ............. ............. 1 5 The Bill .......... ... ....... ... ........... .. ....... ..... .. .. ........... ............. 1 The Wings .... . ......... .... ...... ........... ..... .... ...... ... .. .. ..... ... ... .. 1 TheTail ..... ...... ... .......... . .. ..................... ... ............ ......... .... 19 The Feet .... ...... ........... ....... ........ ...... ......... ......... ..... ......... 1 Feathering . ... . ............ ... .... ... ................ ... ............ ..... ....... .. 1 Intern al Anatomy ....... .... ............. ..... ........ ..... ....... ... ......... .. 1 Diversity in Bird Movement... ......... .. ....... .. .. ......... .. .............. 1 Movement on Land ... .... ..... .. ........ ..................... ........... ... 1 24 Movement in Water ... .... .. ... ..... ....... ........... .. ..... ... .. ..... .. ... 1 Naming and Classification of Birds . ...... ....... ................. ......... 1 History ... . ...... ......... ..... .... ........ ....... .... .................... ........ .. 1 Methods Used to Classify Birds .. ..... .... ......... ....... ........ ..... 1 Binomial Nomenclature and Classification Syste m ..... ...... 1 S The Species ... ..................... ... .. ....... ........... ......... .. ........ ... 1 The F ormation of Species ............. ...... .............. ... ......... 1 Orders a nd Fami lies of World Birds ..... . .. ...... .. ... ........ ... 1 61 Orders and Families of North American Birds ...... .......... ... 1 How Naming and Classifi catio n Can Help You ..... _, ....... .... 1 The Use of Common Names .. .... ..... ......... ........ . .. ............ 1 Evolution of Birds and Avian Flight .. ...... ......... .. ......... ... ........... 1 Bird Distr ibution ........... .. ......... ....... .... ..... .. ..... ... .... .............. 1 Distribution of Land Bir ds ......... .... ... ..... ... ..... ........... ...... 1 Palearctic Region ..... .... ...... ........ .......... ... .... ...... .......... 1 Nearctic Region ...... .. ....... ........ ........ ..... ... .......... ....... 1 Neotropical Region .. .. ....... ........ ................... ...... ....... .. 1 Afrotropical Region ...... ...... .......................................... 1 Oriental Region ... ....... ....... ..... .. .............. ...... ............... 1 8 Australas ian Region .... .... .. ....... .... ........... ... ......... .... .... 1 I sland Distribution .. .... . ................... .... . .... ....... .... .......... . 1 Distribution of Marine Birds ..... ... ........ .... ......... ..... ....... ..... 1 Northern Marine Region ... .... . ...... .. ........ ...... ...... ........ 1 99 Southern Marine Region ... ... ... ............ ... ...... ........... . 1 00 Tropical Marine Region ......... .. ..... .......... .. ............. 1 1 01 Plankton and Bird Distribution ............ ... ...... ........ ..... 1-101 The Importance of Biodiversity ...... ....... .. ....... .. ........ ..... ........ 1 1 06 Appendix A: Orders and Families of World Birds .. ....... ....... ... 1 Appendix B : Orders a nd Families of North American Birds .. .. 1 Appendix C: Geological Time Scal e ........ ..... ............ .. .... ...... 1 Sidebars Sidebar 1: Which Way is Up? ....... ... ... ..... ......... .... .............. ... 1 Cornell L.aboratortt of Ornitholoett


v Sideba r 2: T h e Evolution of an Id ea: Darwin's Theory ............... 1 Sidebar 3: Latin and Gree k Roots of Bio l og i cal Terms ......... ..... 1 CHAPTER 2-A GumE TO BtRD WATCH ING How t o I dent i fy Birds ............. .......... .. ........... ...... . ................ 2 Shape .. .... . ............ . .. .. .. ........ .. ........... .. .... .. . ..................... 2 Post ures an d Flight Patterns ................................................. 2 5 Behaviors ... ..... ..... ... .... . ...... ..... ... ............ ... .......... .. ...... .... 2 Size ......... ......................... ... ......... ...... ....... .... .. ........ ...... .... 2 Compa ring Body Features ... .......... ............ .. .. ... ........ ... . . 2 9 Field Marks .. ..................... .... ....... ......... ........................... 2 0 Head . .............. ............. .. ........ ... .......... .......... .......... 2 Bill S h ape a n d Co lor ...... .. ... . .. ... .. ....................... .. ...... 21 W in gs .......................... .. . ..... .. ........... ........................ 2 1 2 Tail . .............................................................. ..... .... .... 2 Legs ................................. ... ................ .... ................ ... 2 Co l ors a n d Plumage Patterns ... .............. .... .......... .......... ..... 2 13 Songs .. ........ . ... ............... ......... ...... ...... ........ ... .. ............. 2 Habitat .... .. .... . . ....... .. .................... ....... ........... .............. 2 R ange a nd Abundance .... ... .. ....... . .. . ..... ...... . ....... ...... .. 2 9 Time of Year ........... .. ..... .. . ...................... ............. ... ......... 2 1 9 Sort in g Out Birds ... ...... .. .. . ........ . . ... ..... .. ........................ 2 23 Clos in g th e Distance . .......... .. .. .... ... .. ................................... 2 S ittin g Quietly .......................................... ...................... ... 2 P i s hing and Squeak in g ...... ........ ... ........ .. ....... .................... 2 Mobbing ..... ........................... .. ..... .... .. . .. ..... .... ....... .... ...... 2 26 Playback Songs .... . .......... . ...... ...... .... . ..... .... ....... ......... .. 2 28 B i rd Blinds ...... ................................. ....................... .. ...... 2 29 V iewin g B irds ................ .......... .. ........... ..... . .. .. .... . ..... ...... ...... 2 Us in g Binoculars . .......... .. ................... ... .... .. .... .. .... . ... .. .. 2 Pointing Out Birds to Others .................. ......................... .. 2 Select in g Binoculars ...... .. ...................... ........ ........... .... .. ........ 2 Magnification Power ............. ..... ..... ............. ....... ... ........... 2 Light gat h e rin g Capac ity ..... ..... ........ .. .... .. .......................... 2 35 F ield ofView ......................................... .... .... ..................... 2 Resolution ..... .. .................. ........ ................. . .. ................... 2 A l i gnment. ........................... ... ............ .. .. ..................... ..... 2 Binocular Designs .............. ...... ......... ..... ...... .. .. ....... ... .. .. .. 2 Mini Binoculars ......... .................................... .. ................. 2 Binoc ulars for Eyeglass Wearers ................................ .... ..... 2 40 How to S hop fo r Bin ocula r s ........... .. ............ .. .................... 2 How to C l ean Binoculars .......... ....... .... .................................... 2 41 Protecti n g Binoculars ............................................................... 2 41 Select i ng a Spotting Scope and Tripod ...................... ...... ..... ... 2 42 How to Shop for a Spotting Scope ..................................... 2 44 R ecord in g Observations ..... . .. ......... .... .................... . .......... ... 2 C h ecklists .... ...... ..... ...... .... ......................................... ...... 2 46 Journals ......... ........ .... .... ... . .. ........ .................. ......... .. ..... 2 47 Report i ng Rare B irds .................................................. .. ...... 2 54 listi n g Birds ..... ........ ... ............................ ....... ... ................ 2 54 Cou n ting Birds ...... .. .............................. ..... ............................. 2 Hand of' Bird Bio lo8'1


vl Conclusion ......................... ... ..................................... ........... 2 Th e Birder's Essential Resources .... .. ......................... . ...... ...... 2 Sidebars Sidebar 1: Att r acting Birds to Your Yard .................................... 2 Sidebar 2 : How to Calibrate Binocu l ars For Your Eyes .... .......... 2 Sidebar 3: Sketching Birds in the Field ..................................... 2 3 AND FuNcrroN: TH E EXTER NAL BIR.o Feather Tracts ............ ... ......... .. .......... .. ............ ........... ............ 3 Feathe r Form and Function ........................... ............................ 3 Feather Structure ..................................... .... ....................... 3 Types of Feathers ................................................................. 3 Contour Feathers . ..... ..... .. ................ ............................ 3 Down Feathers .... .................. ... .................................... 316 Semip l umes .......................... .............. ..... .... . ......... .... 37 Fil oplumes ... .................................... .......................... 3 Powder Downs ............... .................. ....... .... .. ............ 3 Care of Feathers ............................................................ .......... 3 Preening ............ ........................... ... ......................... .... .... 3 Oiling ...... ......... ............................... ............ .................. 3 Head-Scratching ....................... ... .......... ......................... 3 Bathing ......... .............. ........................................ ............ 3 21 Sunning ............................................. ........ ........................ 3 Anting .............. .. ......................... ................................... 22 Ectoparasites ...... ... ............ ................................ ... ............. 3 Deve lopment of Feathers ...... ...... ............................ ................ 3 Molts and Plumages ................................................... ........... 3 Annua l Molt and Wear Cycles .......................................... 3 Subadult and Definitive P l umages ..................................... 3 Plumage Naming Systems .................................................. 3 Th e Progress i on of a Molt ................................... ... ............ 3 Nonfeathered Areas ... ............................................................. 3 Eyes ................................ .............................................. .... 3 Bill ...... .......... .............................. ....... ............................. .3 Legs and Feet .................................................... ... .............. 3 Other U n feathe r ed Areas ................................................... 3 Col o r s .. ..... . ........ .......... ......... ................ ............................ 3 Pigments ...................... .... ......... ... .. ................................... 3 Abnormalities and Variations in Pigment Col ors ........... 3 Structural Colors ........ ........................................................ 3 Fundi ons of Color and Color Patterns ..................................... 3 Cryptic Coloration and Patterns ........................... ............. 3 Blend ing In ..... ........ .... ................................. ............... 3 Disruptive Coloration ...................... ........................... 3 Countershading ................... ... .. ... .. ................... .......... 3 Behaviors that Aid Concea lment ............. .. .......... ...... ... 3 Consp i cuous Mar kings and Predation ............... ................ 3 64 Reduction of Gla r e for Foraging ..... .. .................................. 3 The Rol e of Color and Pattern in Social Behavior ........ ... .... 35 Species Recognition ........................... ...... .. .... ......... ..... 3 Cornell L.nboratorq of0rnitholo8'1


vii Age R ecog niti o n ........... ......................................... ..... 3 Sex R ecogn iti o n ................ ................ ........ ...... ............. 3 Ind ividual Recognition .. ........................................ .. ..... 3 7 Floc k Attraction ...... ........ ...... ...... .. .. .. ........ .. ................. 3 Sexual Select i on ........ .... ................ ........ ...... .......... .. ... 3 SIDEBARS Sidebar 1: F eat h e r Detective .......... .. ............................... ........... 3 6 Side b ar 2: Feather Facts .. .... .......... ............ .......... ... .................. 3 11 Sid e bar 3: Irid esce n ce .. .............. ...... ......... ..... ...... .............. .... 3 CHAPTER 4-WHAT' s IN s iDE: ANATOMY AND PHYSIOLOGY The Skeletal System .......... .......................... ........ .. .. ................ ... 4 3 Axlal Skeleton .................. .... ............ .. ........ ...... ............... 4 0 Skull .......................................... .............................. .. 4 H yo i d Appa ratus .... ....... .... .. ......................... .... .. , .... 43 Vertebral Co lum n ........................................................ 4 Appendicular S k e l eton .................... .. ........ .... .............. .. .... 4 Pectora l Gi r d l e ..... .. .... ... .. ... ....... ... ...... .. .. . .. ... .. ...... ...... 4 1 9 Bones of the Wing .... .......... ............ .......... .. .. ...... .... .... 4 2 1 Sternum ........... ... ....... ... ................. ...... ......... ............ . 4 Pelvic Girdle .. ............. ... ....... .. ........ . .. ... .................... 4 B o nes of the Hind Limb ........ ........ .. .......... ................... 4 24 The M u scula r System ............. ........ ......... ....... ......................... 4 26 Skeletal Muscle .. ... . ... .... ..................... ...... .. .... ..... ......... 4 Smoot h Muscle ... ...... ...... ... ......... ........... ..... ........ ......... . 4 Cardi ac Muscle .......... .............................................. .. ..... 4 1 The Nervous System ..... .............................. .......... ..... .............. 4 The Neuron .. ................ .......................... . .... .............. ... 4 32 Sensory a nd Motor Neurons .. ...................................... 4 Cent r a l Nervous System ........ ................. .. ............ .... .......... 4 Brain ... ...... . ................................. .. .. ........ ............... .... 4 Spin a l Co r d .............................................. ...... .. ...... .. .. 4 38 Peri pheral Nervous System ..... ........ .. ................ ...... ...... .. 4 C rani al Nerves ... ............................... ........... ....... ...... .. 4 0 Spina l Nerves ............ ............................ .. ................... 4 4 2 Autonomic N ervo u s System ....... ...... ...... ........ . .................. 4 T h e Senses ... ..... .. .. .......... .... .................. ...... .......... .... ........ ...... 4 Vision ......................................... .. ............... .. . .. ..... .......... 4 The Structure of the Eye, ............................ ................. 4 How Birds See .... ........ ..... .......... .......... .. .. ...... .......... 4SO The Ear a nd Hearin g ...... ..... ..... ...... ......... ...... . .................. 4 54 Structure a nd F uncti o n of t h e E ar ................. ............... 4 Hear in g Ability ... ......... ........ ... .................................... 4 Olfacti o n ......................... ..... ..... . . .................. ... ............ ... 4 T aste .......... .... . .. .......... .......... . ... .. .... .. ..................... ........ 4 5 Skin Senses ..... .... ..... .... ........ ................ ........... ..... ........... 4 T he Endocrine System .. .......... ...... .... .. .. .. ............... ... ....... .. ...... 4 Pitu itary Gland ........................ .. ................. ........ ......... ...... 4 T h yroid G l a nd s .......... .... .... ................................ .......... ...... 4 7 4 Parathyroid and Ultimobranchial Glands ......... ...... ............ 4 4 Adrena l Glands ... ..... ................ ................ .... ............... ... 4 7 4 Handbook of Bird Biolo[jt(


viii Gonads .............................................................................. 4 Pancreas ............................. ....... .................................... .... 4 The Circulatory System ................................ .... ........................ 4 76 The Heart ...................... ................................................... 4 Heart Valves .............. ........... ........ ....... .................... .... 4 78 Blood Supply to the Heart lissue ................................. 4 79 Conducting System of the Heart ................ .. ................. 4 Location of the Heart .............................. .. ............ .... ... 4 Blood Vessels .. .. ... ............ ... ..................... ...... . .. .............. 4 Capillaries ..... ......... ... ...... .......... ..... ............... .... ... .. 4 Arterial System .... ......... ... ............ .. ............................. 4 82 Venous System ....... .... ...................... .. ..... .... ..... ........... 4 Blood .... . .... .......... ...... .. ................... ......... ......... ........ .... .. 4 Lymphatic System ................................ .. ........... .. . .... ....... 4 The Respiratory System ....... ... .... ............................................. 4 89 Nostrils and Nasal Cavities ................................................ 4 Pharynx ...................................................................... .... . 4 Larynx ....... ..... ... .. ... ..... ... ..... ......................... .. .................. 4 Trachea ............................ ....... ....... .. ... ...... ... .... ............ .... .. 4 Syrinx ........ ........... ..... .............. ......... .. ..... ... .... ..... ....... ...... 4 Lungs and Air Tubes ....... .. ............. ................ .. .. ................ 4 98 Air Sacs .. .............. .... ...... ....... ............ .. ........................... 4 1 00 Breath i ng and Gas Exchange ........................................... 4 00 Th e Digestive System .... .. .... ....................... ........ ...... .. ............ 4 03 Oral Cavity .............................................. ... .............. ....... 4 03 Bill ............................... ... ................... .................. ..... 4 Tongue ......... ........ ... ... ... ............ ...... .................. .. ...... 4 1 11 Salivary Glands and Saliva .... .. ................................... 4 1 1 Pharynx ................................................. ..... ...... .. ... ... 4 Alimentary Canal .............. ..... .................................... ..... 4 113 Esophagus ... .... .. ................... ... .. ........... ...... .............. .. 4 3 Stomach ................................ ................................... 4 Small Intestine ................. .. ............................ .... ........ 4 Colic Ceca ...... ...... ........... .... ..... ....... .... .............. ....... 4 Large Intestine ... .......... ...... ................. ..... ........... ..... .. 4 C l oaca .............. ........ ............................. .......... .... .... 4 Liver ...... ....... ........ ..................... ....... ........ ...... .. ....... 4 The Urogenital System ........................... ....... ........ ..... ............ 4 Urinary System .................. ...... ....... ........ .................... ... .. 4 Genital S y stem .. .... ... ....................... .............. .. .... ..... ..... 4 Male Genitals ........................................... .. ......... .... .. 4 Female G e nitals ................................. ................... ... 4 Copulation and Fertilization ..................... ... ............... 4 133 Sex Determination ......... .......... ......... ......................... 4 Hormone s and Secondary Sex Char ac ters ....... .... ...... 4 Fac tors Bringing Birds into Breeding Condition ....... ... 4 Metabolism ........... ... ............. ..... .................................... ...... 4 144 Body Temperature .................. ......... ........ .............. ........ ... 4 C ountercurrent Heat-Exchange Systems .... .. ............... 4 Coo ling ..... ................ ........ .................................. ... ... 4 Torpor ....... ... .... ..... .. ........ ......... .... .................. ..... .... 4 3 H eart Size and Heart Rate .... .......... ....... ............... .. ......... 4 Cornell LAboratorq of OrnitholoB!f


Respiratory Rate .............................. ........... ...... .... ...... .... 4 Water and Salt Regulation .... .... ...................................... 4 Lif e Span and Senescence ......................... ... .................... 4 Majo r Anatomical Differences betwe e n Birds and Mamma l s ... 4 Skeleton ............................................................ ............. 4 161 Muscles ...................... ...... .............................................. 4 Nervous System .............................. .............. ..... ....... ... 4 E a r ........... .......... ..... ........ ........ .... ....... .... ........ ..... ..... ......... 4 162 Eye ... ...... ..... .... ........... ...... ... ........ ... ........... ................ ..... 4 162 Circ u latory system ................................................. .......... 4 Respiratory System ........................................ . . ....... ..... 4 162 Digestive System ........ ..... ............................................... . 4 U r ogenital System ............................................... ........ .... 4 Suggested Readings .......... ......................... ......... ................ 4 163 Side bars Sideba r 1: The Amazing World of Avian ESP ....... ......... ........... 4 S i debar 2: Bird Song: From Oboe and Trombon e to Orator and Sopran o ...... ............ ...................... .. ............ ... 494 CHAPTER. s -BIRDS ON TH E MoVE: FLIGHT A N D MIG RATION The Flight Syndrome ... ............. .................................................. 5 Functions of the F li ght Muscles ............... .... ................. ........ ..... 5 7 How Do Birds Fly? .. ..... .... ........ .... ........... ...... .......................... 5 8 Forces Acting on a Bird i n Flight .................. .... .................... 5 9 Gravity ............................ ............. ... ........... .............. 5 10 Lift ................................................................. ..... ........ 5 10 Drag ............................................................................ 5 16 Thrust ................... ... ............ ....... .......... ..................... 5 16 Function of the Tail ........... ......... . ...... ... ....... ....... ......... .. 5 Landing ........ ....... ........ ... ....... ........... ........ ... ... ...... ....... .... 5 Hovering .... .. ..................................................................... 5 Comp lex Control of Flight ......... .... ...... ............ .... ........ ...... 5 30 Wing Loading ................ ....... ....................... ... .......... ......... 51 T urbulenc e .............. ............. .................... ............. ........ .... 5 Variations in Wing Shape and F l ight Sty le ... ...................... 5 Elliptical Wings ................................................. .......... 5 High-speed Wings ...... ................. ............ .................. 58 Slotted High-lift Wings .. ....................... ....................... 59 H igh-Aspect-Ratio Wings ...... ..... ........ ..... .... .... ......... .. 5 4 2 Some Flig h t Facts and Figures ............................................ 5 45 Ai r Speed ..................................................................... 5 Wingbeat Frequency .................................................... 5 Flocking and Flying in Formation .............. ........................ 5 Loss of F l ight ...................................... ..... .......... .. .............. 5-48 Migration ............................................... ................................. 5 5 1 Patterns of Migration ...... ..... ......... .... ..................... ............. 5 The Orig i n and Evolution of Migration ................... .... ........ 5 5 7 Controlling and Synchronizing the Annua l C y cle ............... 5 61 The Physiology of Migration ............ .... ............................. 5 D a ily Timing of Migr ation ................ ...... .................. ........ .. 5 Handbook of' B ird


X The Altitude of Migration ........................ .............. ........ .... 5 Flight Speed and the Progress of Migration ........ ............ .. .. 5 Weather and Migration ...................................................... 5 Migration Routes .... .... .................. .... ...... ........ .... ............ 5 Site Fidelity ...... ......... .... ........... .... ..... ....... ................. 5 Orientation and Navigation ............................ ..... .... ...... ...... ... 5 79 Compass Mec hanisms ... ............................ ....... ........ ...... 5 Sun Compass ..... ...... ..................................... .............. 5 Star Compass ............................................................... 5 Magnetic Compass ...... ......... ...... ............. . .............. 5 89 Navigational Maps ............ .. ... .......... ............................... 5 Sunset Cues ................................................................. 5 Suggested Readings ....... ..... .................... .... ........................... 5 Sidebars Sidebar 1: Flapping Flight. .................... .... ... ........ ...... ...... ........ 5 Sidebar 2: Showdown at Delaware Bay ......... .... ............ ...... ... 5 Sidebar 3: Polarized light... ..................................................... 5 EvoLUTION oF BIR D S A N D A v iA N Fuc ttT Archaeopteryx and Other Urvogels ......... .. ...... .... ... .................... E T he Descent of Birds .................................................................. E Flight Origins ....................................... .. .. ..... ........ ........ ........ .... E Ground-Up (Cursorial) Theory ............................................ E Trees-Down ( Arboreal ) Theory .. .... .................... ...... ....... ..... E Early Bird Flight .................................................................. E The Early Fossil Record of Birds .......... .... ................ ... .. .. ........ ... E 20 Pala eognathous Birds ...................... ............................... .... E Bird Evolution's Big Bang ....................................... .............. .... E Appendix A: Bird Evolution Theories and E ar ly Diapsid Reptiles ................................................................. E 27 Appendix B: Hypothesized Relationships Among Ancient and Modern Bird Groups ........................................................... E Appendix C: Index to Fossil Organisms ........ ........................... E Figure Credits for Appendix C. ...................... ........................... E 34 CttAPTER. 6 -U NDERSTANDI NG BIR.D B E H AV I OR. Questions About Behavior ......................................................... 6 The Proximate Basis of Bird Behavior .... .................. .... .......... .... 6 Ethology, Ornithology, and Instincts ..................................... 6 learned Behavior .......... ..... ..... .. .. ........ .. .. .. ......................... 6 A Comparison of Instincts and learning ......... ... .. ......... .. .... 6 Ultimate Causes of Bird Behavior ..... .... ............. ............ ... ..... 6 Territoriality, Dominance Hierarchies, and Ritualized Aggression ................ ............................. 6 T he Evolution of Ritualized Displays ............................ 6 Courtship Displays .................................... ........ . ........ 6 The Use of Darwinian Evolutionary Theory .............................. 6 Feeding Behavior: Why Do Birds Generally Restrict Their Diets Ignoring Some Edible Foods in Favor of Others? . 6 Cornell


Antipredator B ehavior: Why Do Some Birds Mob Predators? ... ..... ....... .. ... ... .... ....... ........ ..... ..... ......... 6 Nest Spaci ng : Why Do Some Birds Nest in Large Colonies?6 Reproductive Behavior : Why Are There D i ffere n t Kinds of Avian Mating Systems? .. ... ... .... ..... ..... ... ... .. .. ... ......... 6 Reproductive B ehavior: Resource-defense and Female-defense Polygyny ...................... . . .. .... ........... ... 6 Reproductive Behavior: Lek P o l ygy n y .......... .. . ................. 6 Reproductive Behavior: Polyandry ..... . .......... ..... .......... .... 6 77 Mate Choice: Extrapai r Copulations I n Birds ...................... 6 Mate Choice: Why Do Some Birds D i sp l ay E l abo r ate Ornaments? .... ... ..... ................... ... ................. 6 Mate Choice: Why Cooperat e in Courtship Displays? ... .. .. 65 Parental Behavio r : Why Do Some Birds Ignore Lethal Aggression Among Their Nestlings? .... .. ..... ........ . . ..... .. 6 Parental Behavior : Why Are There H elpe r s a t the Nest" That Care For Someone Else' s Offsp ring? ...... ..... ........ ... 6 How to Study Bird Behavior Yourself . ............. ... ......... ........... 6 Suggested R eadi ngs ...... ....... ........... ...... ... ... ..... ..................... 6 S idebars Sidebar 1: Bird Brain s .................... .... ............... .. .... .............. .. 6 16 Sidebar 2: Pla y ...................... ........ ....... ... ........ ..... . ......... ....... 6 19 Sidebar 3 : Defense Behavior ........ .. ....... ..... .... ....... ... ... ............ 6 Sidebar 4: Living in Groups .... .......... ..... ..... ... ...... .... . .. ... .. ..... 6 Sidebar 5 : Length of the Pair Bond .. .... .. .............. ......... .. ........ 6 Sidebar 6 : Bird Families as Model s for Understanding Ourselves ..... ....... .... ............ ..... ..... .......... 6 C tMPTER 7-VoCAL B E HAVIOR What is Sound? ... .... ....... ......... ..... ..... ... ........... .. . ...... ............ 7 Seein g Sounds: Sonagrams and Oscillograms .... ..... ... ...... ... 7 Use ofTape or CD with Chapter Text .............. ........ ............. 7 Understanding Complex Songs ............ .......... ....... .. ..... ... .. 7 9 Vocal Repertoires .......... .............................. ....... .............. .. . . 70 The Problem of Mea ning .................... ... ....... . ........ ........ . 7 11 Song .. . ... . ... ..... ......... ............. ....... .. ............................... 7 1 4 Th e Structure and Functio n of Sounds ....... ..... . ..... ... ......... 79 V oca l Development ......... .. ............. .. ....................................... 7 Vo ca l Development in Songbirds .... ... ................. ........... .. 7 Vo ca l Development in Nonso n gbirds .............. ... ............... 7 Songbi rd Diversity .. .... ........ ........ ....... ... .......... ...... ....... ..... 7 4 Con tro l of Song .. .. ........ .. ...... .......... ... . ................................. .. 7 Variation in Space and Time .... ........ ..... ........... ........ ..... ....... .. 7-4 1 Species Differences .... ......... .. .... ....... ............... ........ ......... 7 2 I ndividual Variation ... . ..... ... ......................... .... ..... .... ...... 7 Song Dia l ec t s .. .... .......... ..... ...... ......... ........... ... .......... .... ... 7 Geographic Variation in Subosc in e Vo ca lizations ........ . ... .. 7 The Diversity of Geographic Patterns in Songbirds ............. 7 Song Change OverTime ....... ......................... .. ............... 7 63 Dialects Over Broad Regions ...... ..... . ....... ... .... ... .... ......... 7 H andbook of B ird BiolO[jlf xi


xii The Functions of Song ................. .......... .................... .... ...... 7 Dawn Chorus ........................ ............... .. ... ... ......... . ... ... 7 Duetting ........ .... .... .............. ,., ...... ........... ......... ............. . 7 7 8 Mimicry ....... .. .......................... .... ........ .......... . ............... 7 F li ght Songs .............. ........................................ ............... 7 Son g R e pertoires ........ ........ ............................................ . 7 Suggested Readings .............................. .................. ...... ........ 7 Appendix A: Descriptions ofTape/ CD Tracks ......... ............... 7 93 Sidebars Sidebar 1: W inn ows Snaps and Spring Thunder-Nonvoca l Sounds ............................................... .... .......... 7 Sidebar 2: Listen Up! ............................................................... 7 Sidebar 3: Pushing the limfts: New Computer Tec hniques for Studying Bird Song ....................................................... 7 Sidebar 4: Do Birds Think? ......................................... ............. 7 Sideba r 5: ''Call Notes" and Their F uncti ons ............................ 7 Sidebar 6: Listening on Your Own ................................ ........... 7 88 CHAPTER 8 -NESTs, E GGs, AND YouNG: BREEDING B IOLOGY OF BIRDS Survival ....................................................................... .............. 8 The Timing of Breeding ........................................................... 80 Bre ed in g T e rritories ............................. .......................... ......... 8 Functio n s of Br eedi n g Territories ........................................ 8 Nests ann Nest Building .......................................................... 8 Func t ions of Nests ........................................... .... .............. 8 Diversity of Nest Sites .................................. .... .................. 8 20 Seaso n a l Changes in Nest Sites ................................ .... ...... 8 Nest Site Selection ..................... .. .. .. ..................... ... ......... 8 D i versity of Nests ................................ ... ........................... 8 The Evolution of Nest Construction .... ... ............ ......... ........ 8 Nest Lining .................... .. .................. ........................... ... 8 Nest-building Behavior ................................................ ..... 8 Sex Roles in Nest Bui lding ............ ...... ......................... 8 Dumti on of Nest Build i ng .................................................. 8 Nest Appropriation and R euse ............. ............................. 8 Eggs ................................ ....... ......................... ..................... .. 8 Egg Structure .. .... ..... ......................................................... 8 Egg Siz e .............. .... ..... ......................... .... .. ........ . ............ 8 70 Egg Shape ........... ................................. . ................ ... ....... 8 Egg Surface Texture ............................................. ............. 8 7 4 Egg Co lor ..................... ................................ ..................... 8 Egg Laying ............................... .. ..... ............ ............ ........ 8 C lutch S i ze ................ ... ...................................... .... .. ....... 8 Patterns in C lutch Size Variation ............. ..................... 8 The Evolut i on oi C l utch Size .. ...... ........... .. ................... 8 Egg and Clutc h Repla ce m ent . ........................................... 8 Number of Broods per Season ........................................... 8 In c ubation .................. .............. ....................... ... ................... 8 3 I ncubation Patch ...................... ............ ........ ... ............... 8 Cornell Laboraton1 ofOmitholo[JIJ


Incubation Period ..... ... ....... .. .. ... .. .... .... ..... ... ....... ....... .... 8 Start of I ncubation .... .. ..... .... ...... ..... . ....... ...... . ......... ... ... 8 Role of the Sexes ......... ............ ... .............. ....... ... ........... 8 Patterns of Attentiveness ..... ........................................... ... 8 Behavior During Incubation ............................................. 8 0 1 Cha nges in Incubation Behavior ...................................... 8 03 Feeding the Mate ................. .......... ................................ 8 OJ Development of Y oung ................................ .............. .. ........ 8 04 Hatching ............................................................... ......... 8 Development at Hatching ...... ......................................... 8 06 Typ i cal A l tricial Young. ... ...... , ..................... .......... 8 0 7 Typi c al Precocial Young .......................................... .. 8 7 Recognition Between Parents and Young ....................... .. 8S Caring forYo un g ... ... ...... .. ........ ...... ....... ................ ......... ...... 8 Feedin g the Young ........................ ..... .............................. 8 D efending the You n g .. . ................................................... 8 Nest Sanitat i on .................. ..... . ........ .... .... ...................... 8 1 36 Brood Parasites .. ................. ........ ......... ...... ............................ 8 Evolulion and Adaptation Among Obligate Brood Parasites .... ........... .................... ......... . ............. 8 B rood Parasite Ploys ...... ..... ........................................ 8 Host Counterploys and Coevol u tio n .......................... 8 Evol ution an d Adaptation in New World Cowbirds .... 8 t 48 Co n clusio n ............................................................................ 8 Suggested Readings ................ ............. .... .. .... . . ........ ......... 8 Sidebars Sidebar 1: Neat Nesting Fact s .......................................... ....... 8 Sidebar 2 : Social Weavers ........... ..... ...... ..... ................... ....... 8 Sidebar3: Oology: From Hobby to Science ..................... ....... 8 Sidebar 4: Creches .. ............. .. ... . . .... . ......... ...... ................... 826 C HAPTER 9-I NDIVIDUALS, PoPULATIONS, AND CoMMUNITIES: THE E coLOGY OF BIRDS Birds as Individuals ..................... .... .. ... ... .. . ... ..... ... .. ............ 9 7 H abita t Sel ection: Choos i ng a Place t o Live ........ . .. ... ..... .... 9 Thermoregulation: Cop in g with H ea t and Cold ........ ....... .. 9 13 Water: A Matter of Economy .............................................. 9 Foraging Ecol ogy: Meeting Energy and Nutritional Demands .................................. .. ................. 9 How Much Food Does a Bird Need?.. .... ... .. ..... .... .... ... 9 23 What T y pes of Food a r e Eaten? ..................................... 9 25 Where a nd How to Forage ........................................... 9 Do Birds Always Forage Optimally? .......... .... ............ .. 9 1 Coping with Envi ronmenta l Flu ctua ti o n s ...... ........ ... .......... 9 3 1 Relationships with Other Indi vidua l s .................. ............... 9 Types of Intraspecif i c Co m petitio n ........... ........ .. ........ 9 Life History Strategies: Putting it All Together .... ...... .......... 9-43 Birds in Popu l at i ons ...... . ...... .. ............................................... 9 Cha r acterist i c s of Bird Populations ............... ... ................. 94 9 Geographic D i s tribut i o n Pattern s .............. ...... .......... 9 Handbook of Bird Bioloett


xiv Population Size .. .. ....... . .. ......... ... ................................. 9 How Do We Determine Populati on Size? .................... 9 What Affec t s Population Size?... ... . ............................. Yb2 What Regul ates Population S ize? ..... .......... ............ . 9 67 Extinction: TI1e Death of the Last Individua l in a Popu l ation ....... ... .............................................. 9 Structu r e of Bird Populations .......... .......... .................. 9 Bird Communities ........................... .. ................ ................. ..... 9 Characteristics of Bird Commun i ties ............... .................. 9 Patterns of Spec ies Richness .............................. ................ 9 85 Effects of Latitude ......... ........ . .......... ...... .............. ..... 9 Effects of Hab i tat Comp l ex i ty and Product i v ity ............ 9 Effects of Habitat Size .................................................. 9 Habitat Patches as "Islands ............... ................. ........ 9 Patterns of Relative Abundance ....... .. ...................... ........ 9 1 Ecological Niches .................. ................................. ........ 9 A r e Bird Communities Organized in Opti mal Ways? ....... 9 04 Birds as Components of Ecosystems ........................... ............ 9 09 Ecological Distr ibuti on of Birds in the Major Terrestrial Ecosystems of North Amer ica ..................................... 9 1 09 Tundra .......................................................... ............. 9 114 Conife r o u s Forest.. ..................................................... 9 1 16 Deciduou s Forest. ................... .... ............................... 9 117 Grassl and .... ..... ........................................................ 9 118 Southwestern Oak Woodland ................................... 9 1 20 Chaparral .... ... ......... ................................. ............. .. 9 1 20 Pinyon Juniper Woodland ......................... ................ 9 121 Sagebrush ..................................... ........... .. .............. 9 121 Scrub Dese rt .............................................................. 9 Two Important Ecotones .... ........ .......... ................... 9 T h e Rol e of B i rds in the Food Chain ................ ................ 9 What if B irds D i sappeared? .......... ..... ............ ................ 9 126 Sidebars Sidebar 1: The Winter Banquet .......................................... .. .... 9 -32 Sidebar 2: The House Finch Hot Zone ....... ............ ........... .. ... 9 Sidebar 3: Ant Followers .......... ................... . ............. ...... ...... 9 Sidebar 4: From B l ackber ries to Beeches: Ecol og i cal Succession in Eastern Deciduous Forests ........ 9 11 0 Sidebar 5: Sapsuc kers, Swallows, Will ows, Aspen, and Rot ... 9 CHAPTER 10-BIRD CoNsERVATION Histori cal Context. ..................................... . . . .. ....... ..... ......... 1 0 Globa l Spread of Humans Beg ins Lhe Extinction Era ........ .. 1 0 Early Ext in ctions in North America and the Caribbean ...... 1 0 6 Modern Extinctions on Mainland North America ............... 1 0 9 Labrador Duck-the Mystery Exti net ion ..................... 1 0 Passenger Pigeon-Market Hunting at its Worst.. ....... 1 0 Caroli n a Parakeet Removal of a Menace ................. 1 0 Eskimo Cur lewThree Strikes in the Wink of an Eye .. 1 0 Cornell Laboratonf of Omitholoa'l


Ivory-billed Woodpecker and Bachman's Warbler-Demise of the Southeastern Forests .. .. ...... ..... ....... 1 0 1 6 Brief History of Bird Conserva tion in the United States .... 1 0 Are North American Birds Disappearing? . ..... . ......... ..... 10 The Forested Northeast . ..... .......... ........ ....... ..... ... ... 1 0 29 Grasslands .. ... ... .. . . ........ . ....... ... .. ... .. ..... ... .. .. . 1 0 30 Southwestern Ripa r ian Habitats . ..... ... ... ......... ...... ... 1 0 36 Shorebirds ........ .... .. ...... ..... .... . .......... ................... 10 Conservation Problems: The Ecology of Extinc tion ......... ....... 1 0 3 8 Birth Rates and Death Rates ........ .. .... ........ .. . .... .. ...... 1 0 Population Increases ... ... . . .. ....... ........ . . . .. ........... . .. 1 040 Direct Exploitation ..... ..... .... ............. .... . .... ......... ...... .. 1 0 Introduced Predators .. ... ............... ..... ........ ....... ... ... ....... 1 0 Chemica l Toxins ........... ..... ... .. .. ...... ..... ......... .... .............. 1 0 Indirect Chemical Pollution .......... ....................... .......... 1 0 Introduced Disease ......... .. ..... ....... ...... .... ...... ...... . ..... . 1058 Habitat Loss .. ........... . .... ..... ... . .... . ... . ........ ... . ....... . .... 1 0 59 Habitat Specialization and the Six Forms of Rarity ...... 1 0 61 1 Widely dist ri buted sm a l l local populations, broad habitat tol e rance ..... . .... .. ........... ... .. .. . . .... 1 0 2 Widely distributed, large local populations narrowly specialized habitat requirements ... ...... . 1 0 63 3 Widely distributed small local populations narrowly specialized habitat requirements . ..... .... . 1 0 64 4. Small geographic range large local populations, broad habitat toleran c e ..... .... ... ........... .. ..... ... .. .... 1 0 65 5. Small geographic range, large l ocal populations, narrowly specialized habitat requirements ........... . 1 0 .65 6. Small g e ographic range, smaJI Iocal populations narrow l y specialized habitat requirements . .. .. ...... 1 0 66 Unique Probl.ems on Islands ....... .. ... ... ... ... . ....... ... .. ..... ... 1 0 Habitat Fragmentation : Mainl and Habitats as Isl ands ...... 1 0 71 Conserva t ion Genetics .. . .... ... ..... ...... . . ... . ..... ............ 1 0 7 4 Conservation Solutions: Tools and Prescription s for Stabilizing Popul a tions ........ . ..... ... .... ..... .. ....... ..... ... 1 0 76 DNA Fingerprinting and Genetic Augmentation ............... 1 0 Popu l ation Vi ability Analysis and Metapopulations ...... . .. 1 0 77 Preserv e Design . ... .. .. ... .. . ... ..... .. ....... . ..... .... ........ .. ... 1 0 78 Habitat Management ... ..... .. .... .. .... .... ........ ... .......... .. ... .. 1 0 E c osyst e m Management ...... .... ........... . .. . ..... ... .... .. ..... 1 0 83 Adapt i ve M a nagement .................. .. .. .. ...... ... . . . .. .. .. ... 10 84 Translocation ................. ... ...... ... ... ..... ... .... .............. .. .... 1 0 Legal Protection ....... ........ .. ... . ... .. ......... .. .... ... . . ... .. .. .. 1 0 Endangered Species Act ...... .... ...... ... ....... .......... .. ... 1 0 Clean Water Act, Section 404 .... .................. . .... ....... 1 0 CITES ..... .. ....................... . ..... .... .. .. .......... ...... .. ..... ... 1 0 93 Bringing Birds Back from the Brink ........................ .. ........ 1 0 94 Wood Duck-Regulated Hunting and Adaptive Manag e ment .... ............. ....... .. ........... .. .. 1 0 Whooping C rane-Protected Habitat and Captive Rearing ............. .. ................................... .. 1 0 97 of Bird Biolo84 )IV


xvi P ereg r i n e F alco n P esticide Regul ation and "Soft Release'' Reintroduction .............. .. ............ . 1 0 00 California Condo r-Wild Capture Captive rea rin g, and Study of "Su rr ogates .... ...... 1 0 02 Maui Parro tbill and Akoheko h e Protected H abitat and Fer al Mammal Control ...... 1 0 03 Why Protect Birds? ....... .... ...... .. .......................................... 1 0 04 Direct Benefits ...... ...... ........ ....... .............. . .................... 1 0 1 05 Food ....................................... ...... ... ..... ................. 1 0 05 Clothing ..... ............................................................. 10 Other Utilitari an Uses ....................... ...................... 1 0 105 Recreational Hunting ............ .... ....... ............ .. ...... ... 1 0 OS Bird Watchi n g .......................... ...... ........ ... ............... 1 0 1 06 I ndirect Benefits ............. .... ............. ....... ........................ 10 Ecolog i cal and Evol utionary Roles ........ . ... .... .. . ... . 1 0 06 Envi ronmental Services ........................... ....... ........ 1 0 07 Biolog i cal Ind i cators ............. .......... ... .......... ........ 1 0 1 08 Genetic I nformation ............................ .................... T 0 09 Scientific Stu dy ........ .. .. ........... ... .... ........ .. ........... 10 Aesthetics and Spi ritu a l Values .. ................. .... .............. 10 What Can Each of Us Do? ....... .............. ... . ...................... 1 01 0 Backyard Con servatio n ............ .. ............. ..... ............ ... 1 0 0 Be a C i t i ze n Sci entist ............... ........ ..... ............ ...... .. 1 0 Adopt a Place .......... .................. ........................ .. ...... .. 1 0 2 L oca l Vigi l ance and Grassroots Acti v ism ... .......... ......... 1 0 Environmental Education ......... .......... ....... ........ ..... .. .. .. 1 0 114 Take a Child B irding., . ....... .. ................ ... ... ... ........ ... 1 014 Con tribute to Conse r vation Orga n izat i o n s ... ... ..... .. ..... 1 0 Never Give Up ...... .. ............ .. .. ....................... ....... ..... 1 0 Sidebars Sidebar 1: A Sum m e r W ithout Bobolinks ............. ................. 1 0 3 1 Sf debar 2: The Best Lai d Plans: What Happens When Con serva tion Effo rts Work Too Well? .......... .. ............ ........ 1 0 Sf debar 3: Hawk Deaths Spur Ac ti o n ..................................... 1 0 54 Sideba r 4: Con servat i on Planning a t Ecoregfo n a l Scales ........ 10 SPECIES lABLE ... ......... ....... ....... ... .. ...... .................. .. ....... ......... I GLOSSARY . ......... ... ....... . ............... . ... . ............ ..................... I 7 AsouTTH'E AuTHORS .................................................... .... ... 61 REFERENC'ES .. .... ... .... .. . ........... .................. ... .. ... ...... .... ,., .. 65 INDEX ...... .... ..... ............. ............ ....... ........ ..... .... .................. 81 Cornell of


Bircls and Humans: A Historical Perspective Sandy Podulka Marie Eckh ardt, and Dani e l Oti s [i] The relationship between birds and humans undoubtedly began as soon as people appeared on the sce ne. By the time the first ances tral human beings appeared, some 14 million years ago, birds had been f l ying and runni11g about for 136 million years Modern humans with ske l etons much like ours first appeared 125 000yearsago, a nd thecountrysideswherethey lived were also home to birds. Humans evolved in a world satu r ated day and night, sum mer and winter, with birds. Knowing and appreciating bi r ds as we do today we can read ily surmise how strong l y they impressed themselves on the minds of our ancestors-how their forms, colors, and sounds appealed to the senses, how their flight spurred imagination, how their periodic absences, timed to the seasons, a r oused curiosity. T hey accord ingly became a pervasive part of our her itage-a preh i storic and hi sto ri c infl uence on our language and literature, our rel igion and mythology our art and our music More recently, birds have been a focus of scientific inquiry, and i t is the science of birds that is the focus of this course. Science, however, is a recent i nnovation. Only i n the last few hundred years, ann particular l y in the l ast century has it evolved as one of our most effect ive tools for understand i ng the world. Before th i s great burst of scient i fic discovery, birds and hum ans h ad coexisted for eons. Hunt-


H Podu/ka, Marie Eckhardt and Daniel OtiS ers, foragers, and farmers, observing the birds that passed through their Jives, asked some of the same questions as modern scientists. Based on their own understanding of how the world works, they also gave their own answers. Often these explanations are charming and ingenious, reflecting an odd mix of carefu l observation and astute deductions with wi ld rumor conjecture, and supernaturalism. Typical of prescientific interpretations are many of the accounts in Aristot le's Historia Animalium. Aristotle (384-322 B .C) knew, for instance, that Common Cuckoos of Europe lay their eggs in the nests of other birds, and that the consequences for the other nestlings were usually dire; in this he is in acc ord with modern science. He departs from the modern view, however, by attrib uting this practice to the cuckoo's wisdom in recognizing its own character defects: "This bird is pre-eminent among birds in the way of cowa rdice; it allows itself to be pecked at by little birds and flies away from their attacks." (A modern scientist might suggest that the cuckoos were being driven off by parent birds try ing to protect their own genetfc inheritance ) "The fact is, the mother-cu c koo is quite conscious of her own cowardice and of the fact that she cou l d never help her young one in an emergency, and so, for the security of the young one she makes of him a ... child in an alien nest." In other words, he believed that the bird behaves like any other responsible person who is unable to carefor a child. More accurately Aristotle unambiguous l y asserts that certain birds migrate with the seasons, something European naturalists were still arguing about 2,000 years later. Some creatures stay putfn winter he says, but 'others m fgrate, qur tting ... the cold countries after the au tumnal equinox to avoid the approacl)ing winter, and after the-spring equinox migrating from warm lands to cool lands to avoid the coming heat. In some cases they migrate from places near at hand, in others they may be said to come from the ends of the world." Although the myriad observations on bird life woven into every aspect of human culture rarely meet today's standards as objective "scientific'' facts, they are fascinating in themselves, If they don't reveal reliable truths about how and why birds function as they do they tell us about something equally real-the intimate ancient and continuing relationship between people and birds. In the following chapters, we presentthe current scientific knowl edge on bird anatomy inside and out. We consider bird evolution and the geographic distribution of birds over the face of the earth. We explain bird movements during migration their use of song, and many other aspects of their behavior. We look at their life cycles, nesting practices and the threats birds 'face in a world u tterly dominated by our species. But before we begin our science-based examination of birds, we want to briefly note the influence of birds in other realms of human culture. We also conside r the origins and early development of the field that has become ornithology. The account roughly chronologica l and roughly organized by theme might be considered a brief history of ornithology s predecessors and offshoots. We can only cover a few of the m ajor highlights but even a scanty knovvledge of the influence Cornell L..aboratortt of


Birds and Humans: A Historical Perspective of birds on the diverse facets of human life can't help but enrich our scientific appreciation of birds. Birds as Food For early humans the greatest attracti on of birds was probably gus tatory. Beside th e recently discovered bones of a Neanderthal man who lived some 50 to 90 thousand years ago, lay the bones of a Great Auk, possib l y the remains of his last meal. Although m on sense tells us that humans feasted o n birds in prehistoric time-S, we have little tangible proof. Fragile bird bones do not fossilize well, especially on land and the few scraps of bird bones that turn up in digs often rest in storage sheds, sometimes for years while the paleontologists study larger, more dramatic finds. In spite of t hi s n e gl ect, we know that early humans hunted birds and that their weapons became increasingly soph i sticated progressing from stones and clubs that they held in the i r hands, to sticks, darts and spears that the y threw and on to snares, bolas, traps an d bows and arrows that required ingenuity to construct and skill to use (Fig. H-1 ). At the same time they must have relied as primitive people do even today on the eggs and nestlings of birds. Until recent l y the Bushmen of the Kalah ar i Desert in South Africa gathered the eggs of weavers as part of their food. Fli ghtless molting waterfowl may have been another seasonal stap le; the y are easily captured if one knows their hiding places. Humans eventually l earned that taming and rearing birds en sured a reliable food supply and several species were domesticated. In the O ld World, specifically Asia, the most notable triumphs were the domestic chicken duck, and goose Th e chicken is probably a form of the Red )unglefowl ( see F ig 1 80) which still lives in the wild in southeastern Asia. Already domesticated in India as early as 3200 B.C., chickens appeared in Egypt about 1500 B.C. and somewhat l ate r in Europe. The domestic duck, a form of Mallard, and the domestic goose, a form of the G r eylag Goose of Eurasia were domesticated at least as early as the chicken Handbook of Bird Bioloalf Figure H 1 Trapp ing Waterfowl for Food in Ancient Egypt: This wall paint ing from the tomb of the Egyptian Kh num-Hotpe (about 7 900 o .c.) shows the operation of a trap designed to Ci!pture various species of geese, du cks, and grebes Additional waterfowl including recognizable pintails Flock nearby. In the surrounding shrubbery area hoopoe a redstart a dove and seve ral shrikes. Photo: All tights reserved Metropolitan Museum of Art (33 .8. 7 8 )


I H Sandtl Podulk.a, Marie Eckhardt a11d Daniel Otis Figure H-2. Ancient Duck Decoys: TIJese wat erfowl decoys, dating from 1 UOO . o., were discovere d in 1924 durin g an ar chaeological excavat ion of Lovelo ck Cave, Nevada. ]he decoys were formed of bulrush stems and e ither painted (lr stu ffed a. The body oft h e deco y was formed by hin ding together bundles of bulntsh stems. Note the careful and a c curate shaping of the head which was constructed separ a t ely and sewn to the bod) ( b II painted d ecoy representing a Canvasback drake. Black and reddish-brawl) pigments were used lu color the head neck, and tail; the n white feathers were tied to the body using iine hemp cord. "Stuffed '' decoys ( n ot s h own ) were topped with the stuffed head of an a c1u,11 duck a n d sometimes part uf the duck's body ski n was str e t ched 0 1 1et rhe bulrus h IJOdy. From Lovelock Cave iJy Llewell y n L Loud ,1nd M. R. //arri ngton 1929, pul>lished b) the University of California Press. Figure H-3. Sitting Bull Wearing Feath ered War Bonnet : Photographed arou n d 1885, the famous Siou x Sitting Bull. is shown here weari n g a war bon net of eagle feathers. In rradition

a p l ucki n g t h e conto u r feathers to leave only t h e down they sewed t h e skins togethe r edging them w i t h t hecol orf ul feathers from t h e head of the male bi rds. Each blan k et required more than 100 s k i ns. Bird skins and feathers have ser ved as orna ments i n many soci eties, i ncluding our own. T h e r oyalty in a n umbe r of New Wo rl d I ndia n tribes wore capes, cloa ks, and headdresses fash ioned fro m feath e r s (Fig. H 3 ). We are all fami liar with t h e flowing headd ress of eagl e feathers, the g l o r y of the Native A m e r ican chief of the p l a ins, at least in the movies. T o the Crees, Chero kees, Natc hez, Z u n is, and many of the Great Plains tr ibes, the eagle was sacred. On the M issour i River in 1742, P ier r e de Ia Verendrye found Assi nibo ine I n d ians tradin g with the Mandans for deer skin s ' carefully d ressed w i t h f u r and feath e rs'' and for "painted feathers;" he no t iced a lso that the Manda n s "worked ver y delicat ely in hai r and feathers." Par rot feather s were h i g h ly esteemed by t h e pre h istoric p u eblo dwe llers of New Mexico, who traded for them with peop les fro m the sout h Macaw feathers, especially, seem to have been a status symbol. T he abo r igi nes of A ustr alia wo r e feathers of coc k atoos and Emus in thei r hair u n ti l recently. T he Alas k a n Eskimos a n d the Ale uts deco r ated their rai n garments with tufts of bri ght l y colored feathers sewn i n par alle l seams; the Porno I ndians deco rated the ir baskets with feathers. In the Pacific, the Hawaiians madeexqu i s i tecloaks f r o m t h e feath ers of honeycreepers; samples ca n be seen in the Bernice P. Bishop Muse u m i n H onolu l u (Fig. H-4) The n atives of Borneo made s i milar cloaks f rom the feathers of the R h i noceros H ornb i II (see F i g 1-82 ) And to the nor th, t h e Chinese fashioned jewe lry fro m feat hers. I n t h e U n ited States i n the late 19t h century, p lumes we r e a fash ionab l e appendage to women's hats, wh ich led t o the decli n e of egret Har1dbook of Bird Bio l ofjlj Figure H-4. Hawaii an Feather Cloaks : Elaborate feather work was already being used in ceremonial garments for hig h ranking Hawaiian chiefs when Captain Cook visited the Hawaiian Islands in the late 18' century. T he red

I H.6 Figur e H-5 W o m a n W e arin g Hat Deco rat e d with E g r e t Plume s : Photographed in Manhattan around 1886, a woman wears a flau ypica f of tile fashions on ate 19"' century America and Europe. Ob taining plumes for the milliner y trades of London Paris, and New York became a lucrative occupation. Plvme harvesting ended in North America when the pvb lie was made aware of the numbers of herons, egrets, and other wading birds being killed for their feathers in Florida rookeries. The resulting ovtcry led to the beginning s of the co nservation move melll with lhe establishment fn 1896 of the first Avdubon Society in Massac/w se/ls (see Ch,1pter 1 0). Photo courtesy of the National Audui>on Society and oth er wad i ng bird populations (fig. H-5). One of t h e strands of early conservat i on moveme nts coa l esced a round opposition to this capricious waste of bird life. Birds in Literature, Culture, and Religion Art If birds have been importa n t mater i ally, as ta ngibl e creat u res, in ou r diets and as so u rces of materials for wa rmth and decorat i on, the idea of the b i rd has perh aps been just as important from ou r pre h istor i c beginn ings. T h e pai nt i ngs made by t h e C ro-Magnon peop l e o n the walls of Lascaux Cave n ear Monti gnac, Fra nee i nclude an occasiona l bird among the oth e r anima l s I n one of these pai n tings made about 17,000 yea r s ago, o n e of the few humans depicted in cave a r t has a mask o r birdlike face; nearby is a long-legged bird, or per haps a b i rd at the top of a stic k or spear throwi ng dev i ce (fig. H-6). Most authorities agree tha t t he paintings beca use of t heir secluded l ocation p robably h ad a sacred o r r i tualistic pur pose rat h er than bei n g m ere l y decorat i ve. T h e same may be true of the drawings of human beings, b i rds a n d Cornell L.aboraton1 of O lo9'1


Birds and Humans: A HistoricaL Perspective other an imals d o n e a bout 6,000 years ago o n t h e walls ofTajo Se g ura i n S pain The Lascau x and othe r pai n t ings suggest that eve n a t thi s earl y d ate, b i rds m ay h ave assumed so me kind of symbol i c meaning in the human mind, and the pi c tures r epresen t m ore tha n they actu a l l y portray I n the h istori c p eriod, bird s are present i n the vis u a I art of v i rtually eve r y c u l ture i n every p ar t of th e world I n the Arctic, the Eskimos carved bird s in wal rus ivory. For th e Senu fo of the wes t ern Sudan a bird was a lri b a I emble m used to d ecora t e masks and o th e r ob j ec t s Th e court paint e r s of Mugha l I ndia p ainte d bird s exquisite ly. both as i n c id e ntal e l emen t s i n court and l andscap e sce nes and as the mnin subjec t s in n atura l h istory p a intings. TheAborigines of A u s tr alia painted Emus on r ocks. The standa rd s of Roman armies bore the i mage of eag les. Birds deco r a t e d the go l rl cups of kings in Mycenae in ancient Greece and rhe musica l instru ments of the Anatolian kin gdoms oi w h at i s now Turk ey Stone-ca r ved birds s i t in stone-carved trees in A n gkvr Wal in Thailand. T h e image of t h e eaglelike thunderb ird" was ofte n por trayed by the Native Americans o i North A m erica, to w hom it was a n important e l ement of mythology, capa bl e of p roduci n g rain, thunder and lightn in g (Fig. H-7). The N avaho could m a k e an owl playi n g the eat's c r adle game with stri n g; the Pomo of California cou ld con struct a hummingbi rd. Bird motifs appear often in theartofth e Inca and Aztec. From C hina, an a n c i e n t ceramic pot a l most 5,000 years old depicts a sto rk hol d i n g a fis h atthe t i p of its b il l. B y 3000 B.C., 1 h e E gyp t i ans b egan of Bird BioiO[jlf H71 Figure H-6. The Bird-man of Lascaux: I n thi s derail oi a we ll-known Paleo lithi c cave paillli n g from Lascaux Cave in southern Fr.mce, a bird -headed man lperh,lps wearing a bird-shaped mask) is depicted with a c har ging bison Nearby is, bird v,uious l y illlerpreted as being long-leesert or perching o n a pol e or spear-throwing device. Photo by C h ar les ,mr/ Lenars I Corbis Figure H -7. Thunderbird T otem Pole: The eagl e/ike !lwnrlerbirrl is an impor tant mythological figure to native c ul tures thr oug h out Nor t h Americ,J. They believe it has the power to produce rain thunder, and litJhtning Certain Native American groups o f northwestern Nort h A merica believe the llwnderbird cre.l!e d t/1e world and its carved image appear s frequently o n t otem poles and masks. Her e a thunderbird sit s atop a totem pole in Stanley P.1rk, Vancouver, British Columbia Photo b y n1 Purcell Team I Corbis.


I H.8 F ig ure H-8. Shrik e an d B a mboo : Painted by Li An-chung, an artist at the Hsuan-ho PaintingAcaclemyduring the reign or Emperor Hui-Tzung of the Nort'/1 Sung Dy nasty, "Shrike and BambooH is typ ical of the "bird-and-flowerH genre of Chinese Paincing. The bird is re-creaced in exquisite decail in a simple setting of bamboo leaves and branches. The medium is color and ink on silk. Painting courtesy of The National Palace Museum, Taipei, Taiwan, RepublicofChina. Podulka, Marie Eckhardt, and Daniel Otis using paintings and sculptures of b irds to adorn the friezes ofbu i l dings and the tombs of royalty. One picture from a tomb depicts five species of geese, three so fai t h fully drawn as to be i dentifiab le. Notewo r thy among the world's o rnitho l ogical a rt a r e the bird paintings of China. Even a thousand year s ago they were so popu lar thatthey constituted an e ntir e genre known as "bird-a nd-flower paint ing" (Fig H-8). Although the artists took pains to observe b irds with great care and p a int them with extraordi nary accuracy, the pai n tings often had a symbo li c dimension as well, different birds representing certa i n Buddhist or Confucian qualities and ideals. Far from being stiff, anal ytical case studies, these paintings present l iv e ly, gracef ul, h armonious scenes of perhaps slig htly idea l ized birds in n a tural surroundings. The serene portrayal of birds in a carefull y selected context of a few f lowers, v ines, g rasses, and rock s co ntinues today as a motif in Chinese painting. The a rray of uses to which birds have been put in Western a rt is m u c h broader. Of the legions of Western artists who have pmtrayed bi rds i n some fashion, we can onl y menti o n a few. The depictions reflect an extraordinary range of human ingenuity. Some painters have been intr i gued by the birds themselves and portray them with varying degrees of realism, a n d sometimes birds are i n cidenta l elements in l andscapes, as i n Breughal's "The Return of the Hunters." Albrecht Durer had clearly studied b ird wings carefully; t h e wings of som e of the a ngels and cherubim floati n g about in his paintings are str iking l y realistic. I n the United States, among those who have painted btrds i s Andrew Wyeth, who painted two dead crows dangling against a white woodshed wall in bright sunlight; he seems equally inte rested in the abstract pattern oft he corpses against the wall and in the crows as dead creatures. Cornell Laboratort.j ofOrnitholoatt


Birds and Humans: A Historical Pi!tspective Oth e r painters use birds more as a means to an end, to express the multitude of quali ties we associate wit h t hem. Brancusi's h i ghly abstract "Bird i n Space'' has a n aerodynamic grace. I n a few Georgi a O'Keefe pai ntings, c rows appear as b lack blurs slicing through the sky. T h e birds in Van Gogh's last pai n ting, "Wheat F i e l d with Crows," seem ratheromfnous Birds may also appear as stylized, 1conic elements, as i n Paul K lee's "Landscape with Yell ow B irds" and ''Twitter ing Mac hine." Rnally, in some paintings the fact t hat i t is a bird t hat is being portrayed may be almost i ncidental-it is the form t h a t interests the painter. O r ; the use of a bird may be del iberately in congruous, as i n the work of some of the surrealists. Reliaion From abou t I 300 B.C., the po lyth eistic r eligion of the Egyptians embraced both real and i maginary bi rds. To them lhe embodi ment of the s u n was the fanciful phoen ix, a beaut i f u l bird that burned itself u p ever y five hundred years and rose from its own ashes yout hf u l again a symbol of i m mortality (Fig. H 9 ) The Egyptians held the very real i b i s so sacred t hat i n m a n y a royal tomb they buried an embalmed i bis wrapped in cloth a n d painted. Modern h istor ians regard t h e fi rst event5 of the B i ble as taking p lace in about the 20th centur y B.C.Aimost40speciesofb ir dsaremen tioned-the doves most f requently-in ways that s h ow a knowledge of their hablts a n d a n appr eciatio n for t h eir g race and beauty. Indeed, it doesn 't seem farfetched to s uggest that the idea of t h e angel owes someth i n g to ob s ervatio n s of birds, whic h often appeur as symbols of t r a nscendence and as messengers from the gods. Lik e Ar i stotle in our earlier anecdote, the writer in Job 39:13-1 7 sees accurately but repo1ts somewhat anthropomo rphically: '' T h e w ings of t h e ostrich wave proud ly; but are t hey t h e pi n ions and plum age of love? For she leaves her eggs to t h e earth, and lets them be warmed on the g r ound, for getting t hat a foot may crush them, a n d that the wi l d beast may tra m ple them. She deals cruell y with her young, as if they wer e not h e rs; though her labor be in vain, yet she hus no fear; because God has made her forget wisdom, and given her no shar e in u nderst( lflding." I n t h e religious festival s of many peoples thr oughout the ages, feathers were used as sym bols and participants often wore feathergilr-Handbook of Bird BiolO[Jii H.9 Fi gure H-9 The Phoenix : The phoenix, a myrhical bird that under goes resu/ar rebirth by (Ire approt'S in the myths of numerous hum!ln wltures throughout history Irs physical o1ppear iinCe and story vary greatly among cu l tures. According to one curre111 version oi the myth every 500 years the phoenix, .;ensing own death appro,Jch ing builds ils O\'Vn fvnetu/ p yre and sets lire t o itse lf, heing reborn out of its own ashes. /Is first appearanre is in ancient Egypt in the guis& uf the sacred heron like H Benu bird, which recreates ilself dally In lf1eraysoltheriMng s un. TheChi ne>e rersJOf! of the phoenix, often seen in paintings, is a fanciful c reature callecl the Feng-Huang whose elaborate plumage resembles that or <1 peacock. In western cultures, the phoenix is an eagle/ike bird, often depicted in medi eval illustratiom or on co.1ts of arms as arising ow of if ames. Christians adopted rhe phoenix as a symbol oi resurrection and immortalit y. The sym bolism of re birth is i mportant even in modern rimes : the i llustration shown here is adapter/ from the loso u( the Phoenix Assuram : e Co mpany, symbolizing the need for lite ins urJn cc. From Symbol s Signs and Their Meaning and Uses in Design, Sec und Edition b y Amold Whittick, 797 1 l'u/J/ished by L. Hill, Lo11don. I


I H10 Figure H-10. Types of W a n ds u s e d i n N a ti ve Ame rican Eagle Cal u met, and Fea t h er Dances: Calumer (ceremonial pipe! and Eagle Dances were used by many Notive American tribes to greet strangers, to create ceremonial friend ships, to bring success in hunting or war, to bring good ft,cko r counter bad luck to cure sickness orto make peace between warring tribes. The original calumet w a s a pipe decorated with a fan of eagle feathers. Over lime, it became mere/)' a wand with feather decor.1tions, as shown by the four examples here The Plains ( Sioux ) wand is also decorated with Pi lea ted Woodpecker scalps. F r om India n Dances of North America b)' Reginald and Gladys Laubin. Copyright 1977 b y the University of Oklahoma Re printed with permission. YUcili Cherokee Sandq Podulka, Marie Eckhardt, and Daniel Otis ments on these special occasions (Fig H 10 ). The Plains Indians carried dried bird skins in their medicine bundles and decorated the calumet, the sacred "peace pipe ," with feathers, heads, or skins -red for war, white for peace. The Pueblo I ndians fastened feathers to their wands and prayer sticks. Sev eral North American tribes stil l use ieathers of eagles and other raptors in ceremonial displays. F olklore Peoples whose cultures seem quite unrelated often have simi lar legends and folklore motifs. The Old Testament story of Noah sending forth a dove to find land for instance has many parallels, incl u ding the Delaware Indian l i ef that a loo n led the survivors of a -flood to dry land. On a similar theme, according to the Crow I ncli aris of Montana, diving ducks sent by the Creator dove down under primeval waters and brought up mud to make the Earth. Symbols, too, are often the same in d i fferent c ultures. Large raptors are almost always symbols of power and strength. Thus, the eagle feather was fltti ng for the headdress of a Native American chief, and the bird itself was tho u ght f i tting to represent Zeus. Owls were symbol s of mystery, appropriate companions of witches (Fig. H 1 1}. Because of the ow l's ghostly habit of hooting at night they portended disaster. On the ot h er hand, the eye of a n owl worn about the neck, warded off evil spirits ; a cure for fai I ing eyesight was to eat the eye of an owl; owl soup was considered helpful with whooping cough. Owls also sym bolized wisdom Because of the binocu lar vision that gives the owl a knowing expression, a number of stories feature the "wise old owl." All the nightjars, the family to whi o h the Whip-poor-will, C huck -w ill's-widow, and Common Poorwill (see Fig. 4-128) belong, are nocturna l and have very large eyes and low call s that in some soci eties spell doom. The call of the Whip poo r -will foretold a death to a New England settler. The cal l s of its relatives for etold the length of life to a South American I ndian. Even today the natives of certain parts of South America and the West Indies bel I eve that the calls of the nightjars are the voices of lost souls or ghosts. Cornell Laboraton1 of


Birds a11d Humans: A Historical Perspective Like the owl both th e rav e n and crow have dual characters-good and ev il. For the crow, ther e was a chant: "On e for so rr ow, two for mirth, three for marriage, fo u r for b i rth.'' In m os t folklores the black-plumaged birds are threateni n g, their o n ce-wh ite feathers b l acke n ed by the go d s f o r their evi l deeds Accor ding to one l ege n d, the gods ca ught the pu r e w hite r aven stea l in g wate r an d punished it b y turning its feathe r s black To som e people, a raven's har s h ca ll foretto>l l s deat h ; to oth e r s i t means that the bird i s ca r ry in g a message to the gods. O n e has o n l y to see a r aven f l y croak in g into the distance to sy m pa thi ze with earl y humans fear i n g that the rav e n had seen the i r misdeeds and was on lts way to report them to th e gods. Thr oug h o u t Eur ope, the noisy consp i c u o u s c u c koo fo r e cast coming events-rain the a rrival of spring o r port ents in t h e affairs o f men. In J apa n outings to hear t.he first notes of the c uckoo were once a p o pu l a r spring entertainment. Other spec ies of bird s f i guring promi ne ntl y i n fo l k l o r e i n clude t h e loon for madness the dove f o r pea ce, the swan fo r pride, the goose for conTusi on, and the swa llow f o r travel. As with the c ro w, a s in gle magp i e meant sorrow and two portended joy. Even the b e h avior of the bird was sometimes important in Germa n y, a woodpeckerfl ying to the right was a s i g n of good l uck. In deed, a bird's behavior could even influen ce the destiny of nat i o ns. Pliny the Elder ( 23 79 A D.) te ll s of specia l Roman fighting cocks whose manner of eati n g grai n was thought to fo r etell the li kelihood of success of s t ate endeavors and to i n f l u ence wheth e r the y were ac tuall y unde r taken. In Indi a among thejains a sect n oted for its extreme rev e r ence fo r life i n all its forms, it is co n sidered an act of v i rtue to f r ee a cage d bird Par adoxically, a trade has g rown up of capturi n g birds and bringing them to the market so th e )a ins can f r ee them. Th e ] a i ns also operate a hospital for sick a n d injured birds; carnivorous birds such as h awks and owls are t r eated, but only as o u tpat i ents Fol k l o r e a l so reco unts how ce rtain birds got some of their c har acter i s tics. According to l ege n d (see Turner 1 985, p. 233 in Suggested Read ings), the Red Crossbill (see Fig. 4-1 1 9 ) twisted its beak o n the nailsoftheCross,'' and the European Robin (see Fig 21 b) "sco r c h ed it5 breast bri gh t red while steali n g fire from the s un. T h e Yellow be llied Sapsucker is said to have "acquired its many hues as con solatory g ift s f rom other birds beca use i t had been too tips y on birch juice to attend the officia l distribution of colors.'' Lit erature At the found at i on of many societies' c ultural h eritage are ep i c poems and sto ries based part l y o n ancientfact and passed o n b y word of mouth and late r i n writi n g. Some tales tell of the o r igin of t h e people, their ear l y way of life, and their beliefs; others a re am u sing. Many in c lude bird s in one way or anothe r By the 1 6 th ce ntury B.C., the Greeks h ad a written language, partly hieroglyphi c a n d parl'ly a l phabet. T h e /1/iac/and The Odyssey, the two Handbook of Bird BiolO[JL/ H11 I Figure H 11. Eastern Screech-Owl: With their g h ostly screeching ,md hoO ing c.11/s given under cover of darkness, it is not surprising that owls have ieawrecl prominellll y in folklore through the centuries. Tl1ey are often co nsidered nmens of bad for tune orsyml>ols of mys tery, Yet, l>ecause. of their large eye_< and intelligent expression, owls also sym bolize wisdom. Phn to colirtesy of Mik e 1-lnpiak/ CLO.


I H Figure H-12. Bird s in Aesop' s Fables: A var i ety of bird charac ters appear in Aesop's Fables, a ncie111 tales wilh a moral Two fables are shown here. In Crow a nd The Pitc h er," the is encouraged to use his er h er wits to ove r come a n obst.Jcle. In "The Eagleancl Tle Cro11t, the reader i s w<1med ,1gainst overra lin g his abili ries. Jllustralionti'Om Baby's Own Aesop IJ)' Walter Cran e 18ll7. Photo co pyrighl Corbis. Sandt! Podtl/k,a. Mar i e Eckhardt. and Danie l Otis g reat works a ttribut e d to H o m e r were written in th e ghce ntu ry B.C. T hese epic poems poetically im mortalized the Greek gods, man y of w h o m were associate d with birds-an owl w1th Ath e na, god dess of wisdom; a dove w ith Aphrodite, go ddess of beauty; a fal co n with Apollo, god of the sun; a nd an eag l e with Zeus, kin g oi the gods A eso p's f ab les, origina tin g orall y abo ut the ce n tury B.C. a n d a pp ea rin g in earl y Englis h i n the 9'11 centur y A.D., contain ed many bird c h araders, i ncludin g the cock, c r ane, swallow, sto rk jay, pea cock, goose, n1g htin ga le, eag le, and c r ow. Eac h fable h

Birds and H u mans; A H istorica l Perspective M inor Bird, a nd "On a Bird S in ging in It s Sleep." I n "Dust of Snow," h e wrote The way a crow shook do w n on me a dustofsnow from a h emlock tree h as given my h eart a change oimood and saved some part o( a clay I had rued. Many writings for c hildren dea l with b irds, including Edward L ea r s ''T h e Owl and the Pussycat," Robert McCl usky's Make Way for Ducklings a nd E B. White's classics The Trumpet of the Swan a nd Stewart LiUie. ( Stewar t hi mself is a mouse. but his r oma n tic interest i s a small songbird nam ed Margalo.) I f we ven ture yet further into the realm of popular culture we again find swarms of birds litera lly, in thecaseofHitchcock's famous movie T h e Birds And we mustn't forget Daffy a nd Donald, Foghorn L eg h orn, H eck l e and ) ec k le, Roadrunner, and Tweetie Bird, althoug h we'll admit that they probab l y don 't often attract the atte n tion of seri o u s orn ithologists, M usic and D ance Birds, with their t r emendo u s d iversity of p l umage displays, hab its, songs, and cal ls, h ave inspired the imagination and wond e r of peop l e throughout time-and h ave thu s been included in some form i n man y ceremonies, dances, and mus i cal compos iti o ns. Music and Dance of Indi ge n o u s Cultures M u sic a nd dan ce are tod ay co nsider ed forrns of e nt e r tainment by most p eop le, but to traditional n ative peop les, both past and present, they may be powerfu l forces in th e human expe r ience. T heir power comes fro m the fact th at music dance are often import ant co mpo n en t s of ritual s a nd ce remonies that have great spi ritua l signiiicance. Birds, because the y were ofte n seen as intermediaries between the physical and s piritual worl ds, were oflen represe n ted in man y ce re monies. But the way many indigenous cu l tures think about thefr re lation s hi p with birds a n d th e s piri tual world is so differe n t from the way western c ulture s view these things that it is ex tr e m e l y difficult to a d e quat e l y exp l a in the i r beliefs in th i s brief passage; indeed, 111ost westerne r s ma y find the concepts n ei! rl y impossible (r) grasp without l ong term s t udy. T o ma n y indige n ous peoples, the land is a sour ce of l ife. But it is more than jus t a sou r ce of food an d livelihood, ior there is a core per ce ption that all aspec t s ofexlstence-inclu d i ngspirltuality c ultur e and soc ial l ife-are i n sepa r ably conn ecte d to the ina n imate world of mountains, rive rs, skies, a nd r ocks and the living world o f p eo ple, o ther anim a ls, a nd p l ants. S piritual m ean ing incl uding a connec tion Handbook of Bird BiolO[ilj Hl3 I


I H 1 4 Figure H-1 3 Feathered Ceremonial Co stume s of Indigenous People s : a. A Native American dance costume fe< turing an tlaborate bustle is worn by a dancer performfng at the Yakima /ndi,m Nation Powwow in While Sw,111, ington. Photo by jay Syverson!Corbis. b. A New Guineantrtbesnmn at Mount Hagen. PilptM New Guinea wearing an ornate ceremonial headdress composed nf many feathers of birds-of-parJdise ancl other species. Photo by Quadril lion/Corbis. a to the past (ancestors), the present, and the? future is found in many of the connect ion s within this complex web. Ceremonies, rites, songs, and dances were c r eated to maintain harmony and balance withi n this web-and these often incorporated birds because of their spi ritu a l or ecological significa n ce. Sometimes just the physical appearance of birds was i mitated or represented but at other times their displays, vocalizations, and other behaviors were incorporated 35 well. The specif i c be li efs, legends, and ceremonies are as varied as the cu l tures. Bird spirits were invoked to render strengt h to provide guidance and wisdom, to heal the sick to communicate with ancestors, to enhance fertility, and to provide food and rain. In the fo llowing paragraphs are j ust a few examp les of the many ways birds were, and often still are incorporated into the music dance, and other types of ceremon ies of indigenous peoples. Birds frequent l y appeared in ceremon ies in the form of feathers or physi cal images (teal or mythical). Familiar to most people are the feathered h eaddresses and bustles !hat mimic...the spread tail ieathcrs of s trutting birds ( F i g H-13). Feilthers are also used to adorn ceremon ial objects such as the prayer sticks of the Zun i of Arizona and New Mex ico. Each prayer stirk is decorated with a specific type and number of feat hers, each feather having a special meanin g (Bol 1998). Bird images are re-created in ceremonial masks totem poles, and other objects. TI1e Tlingit people of Alilska for example, often used the im age of t h e raven because of its signifi cance in their traditions. Many birds are represented as kachinas { dolls r epresen ting ancestra l spirits) in Hopi and Pueb l o trad i tion. One bird that is represented in traditiona l native dances all across the North American contin ent is the eagle. To many North American tribes, it is the greatest and most powerful of birds, ruler of the air and t h e creat ure s in it; powerful, fierce, and fearless. The Iroquois Eagl e Dance, still peaformed today, was used throughout time to bring luck Cornell l.aboratortf of Ornitholoetf


in hunting Although it evolved from ce r emonies about peace and wa r it now ser ves to ce lebr a t e ex i sting f r iendships, to heal illness, and as a giving of thanks ( F ig. H-14). Because they noticed birds performing ce rt a in behaviors at the tim e of year when rain falls, many t rad i tio n al peoples assumed that th e bird s wer e abl e t o bring r a in Thus they d eve l oped dances to lmftate these behaviors so th at they, too, cou ld bring r a in. For examp l e, the Tarahuma r a India n s of Mexico perform two springtim e dances that i m itate the strutt ing courtship ritual of the maleWildTurkey-a d ispl ay that occurs during t h e rain y spr i ng seaso n. Similarly the Zuni and Hopi of t h e southwestern Unite d States try to bring r a in by invoking the hummingbird as the med i ator be tween humans and the gods ( because hummingbird s migrate bac k from their winter in g g round s and ap p ear in the southwest during the r ai n y springti m e). Bird activ ities were a l so assoc i ated w ith hunting and f ood. In o n e ceremony in the Torres Strait, between New Guin-ea and Australia dancers mimic the Torr esian I mperial-Pigeon whi ch swings its head up and down duringoneofitsdisplays (Fig. H-15). The cere mon y serves as a young m a n's initiation and recognition, as well as a n appeal for a n abunda n t food supply ( the pi geon i s a n important source of food in the region ) Birds w ith e l abora t e courts hip displays wer e often imitated by trad i tiona l cu l tu res. Of particular i nterest wer e birds t h at disp l ayed in leks (see Ch. 6, R eprod u ct i ve Behavior : L ek Pol ygyny): in these species, males gather at trad i tional sites and perform showy d is plays, competing with each other for the atte nti ons of t h e fem ales, w h o visit H andbook of' Bird H Figure H -14. The Seneca Eagle D.1nce : In this painting from aro und I 900 by Ernest Smith of the Tonawanda R eser v,1tion New York, four dancers perfomr the Seneca Eagle Dance Each wears an Iroquoiss t y le cos tume includins leg gings, a decorated breechclo th or kilt, armbands, and a close-filling c.1p with a single eagle feather. Notice also, th e feathered wands. Members of the Sen eca bran ch of the Iroquois Natio n still perform an Eagle Dance to ellis day. Originally it was associated wirh peace and war, but in modern times it i s per formed to celebrate friendships, cure disease bring rain, uplift the down hearted and as a thanksgiving Rece nt performances hav e had two dancet5, but accounts from the early I 900s, such as this paiming, show four dancers. Smllil so n ian In stitution, Bureau of American Ethnology. Figure H-15. Torresian Impe rial-Pi geon: In a ceremony in the Torres Strai t between New Guinea and Australia dancers imitate tl1e head-bobbing dis plays of the Torresian Imp erial-Pigeon. Detail ofplate by Lilian Medla nd, f rom Birds of New Gu inea, by Tom Ired ale, I 956. Melbourne, Australia : Georgian House. I


I H M Figure H-16. The Prairie-Chi c ken Dance: a. Ethnographers R egi11ald anrl Gladys Laui>Tn s tudied and perform ed the dances of American Plains Indian s from the 7 930s through tl1e /9S0s. He re, Sandtt Podrdka, Marie Ed;hardt, aru.L Da11iel Otis the l eks on l y to c h oose a male and mate. One group t hat mimics a l e kkin g s pecies is the C h ukchi oi Siberia, who imi tate th e disp l ay of the Ruff. Mal e Ruff s gat h e r in leks, ta k e up stances about a fool apart, an d sile n tly confront eac h other i n simu l ated attacks (see Fig. 6-40) In the B avar i a n high l a nds, performers imi tat e th e l e k king displa y of the B l ack Cock' ( p r obab l y a loca l common n am e for eith er the Bl ack Grou se or t h e Eurasia n Capercaillie), in whi ch the b irds posture, dan ce, and engage in mock f i ghts. I n the tr aditional Bava r ian danc e call ed theSchuhp/att ler, a man jumps a l ong beh i nd h i s partner clickin g h i s tong u e and cl app i ng. Eventua lly he st rikes the g r o un d with o n e o r both ha nds and bounds toward h e r with arms out spread or hanging down. A l thoug h the dance is now performed for recreat ion, its similarit y to other bird dances indicates that it ori g i nat ed l o n g ago f rom beliefs asso ciat in g birds and the spiritua l world ( A rm strong 1975 ) The B l ackfoot In dians and many other tribes from the plains of Nort h America imitat e the dance oft h e Sage G rouseanothe r l e kkin g speciesw hich e n gages i n spectacul a r displays involving hundreds of b i rds Many tribes f rom t h e North Amer ican p l ains a l so had a Prairie-Chi c ken Dance in which m en imita ted the e n e r getic lekking display of mal e prairie-chic k e n s (Fig. H-16). T h e Jlvaro In dians o f Peru and Ecuador i mitate the l ekking a ntics of the A n dean Cock-ofth e Rock (see Fig. 7 28 } I n additio n the Es kimos had a Ruff e d Grouse Danc e i n w hich t h e p rin cipal danc e r would dance on hi s knees and imitate a Mr. Laubin p e rfonns /he Prairie-Chi c k e n Dance. Many tribes, including the Lakota, Oglala S ioux, Blarkfe e t and Plain s Cree, originally had dances t o h c mor a nd b imit a t e the springtime displays u( prairie chickens .md other grouse. Tl1e PrairieC hi c ken Dance, while ent e rtaining. also celebrated the tribe's survival through m a l e grouse drumming (see C h 7, Sidebar 1, F i g. A). Although Ruff e d Grouse do not assemble i n leks, the i r display s a r e q ui te i mpressive. Th e cour tship displays of cranes h ave a ttracted t h e a tt e nflon of man y c ultu res a round the globe. A l though they d o not d i sp l ay in l e ks mal e and fema l e cra nes of many species perform e l aborate dances in sp ring e i t h e r t o strengthen an existi n g pai r bond or to est ablish a new o n e (see Fig. 6 19 ) Thecircu l armovementsofth edancesofsomespe cies were assoc i ated with the season a l move m e nts of the sun and in man y cultures these move ments came to represent fertility and death. For exa mple, the Osk r its oi Siber i a perform a funera l dance wearing cra n e s k ins. the winter and the coming of spring. T11e dancer struts and jumps, stamping his feet $ hakin g his s houlders. 11nd quiverin g his whole body, while litt ering guttur al clucking calls. Photo from Indian Dances of Nonh America b y Regin.'lld ilnd Gladys / aubin. Cop)' righ t 1971 b y the U n iversi/y of Oklahoma Press. Reprinted witl 1 p ermission. b. During its co urtship display the mal e Great e r Prai rie-Chicken performs moves simi/a t to those of its hum,ltl imil

tures, i ncludin g musi c and dance. For the Temiars of Malaysia, knowing a path thr oug h the jungle is essential to s u rvival. To lose one's path can be fatal. This import a n ceof"a path" is a metaphorfor h owtheyperceive the mselves relative t o their e n viron m e nt t heir society, and the cosmos. Consequ e ntly, they believe that illness results w hen a person's soul gets waylaid. T reatment i n vo lves sin g in g w hat's called a "way" ( a song that represent s a pathway), fin d in g the soul and leadin g i l h ome During ceremo nies, musical sounds are used to modify the feelings of the par t icipants i n many d ifferen t ways. On e of the sounds i n voked is the call of the Golden-throated Barbet. Its two -toned, puls ing sound bri ngs about a sense of l ong ing. The T e m iar bel ieve that it beats in rhy thm with one's heart moving t h e heart to l ong for a loved one o r for a deceased r e la tive. The rhythm i s r e -created dur ing ceremon ies b y bamboo percussion and drums, and i s used to bring about a trance state and co n nect with a spirit guid e ( Roseman 199 1 ) (Fig H 1 7 ). The Kal u li peop l e of t h e trop i cal rain forest in Papua, New Gu inea integrate birds i nto every aspect of their traditions, includin g t h e i r musi c and dance. Birds are consi dered spi r i t reflections of the ir dead; mediators between t h e l iv in g world a n d Kaluli w h o have died a n d r eappeare d i n the form of birds. Birds are thus n ot seen simp l y as creatures separate from humans, and their sounds have profound effects on livin g people. T h e diffe rent types of birds r epresent spir its from d i fferent soci a l categories (men women, o ld, young) a n d from diff e rent tempe r a ments (angry, docile, hostile, cranky, and so on). One examp l e of the i ntegration of b irds and the i r sounds with Kalu I i music and dance is the "weep ing ceremony" of sor row or loss.l n these cere monies the performer takes on characteristics of a fruit-dove, mak ing Handbook of' Bird H Figure H -17. Temiar Trancin g Ceremo n y: During Crancing of tile Temiar people of Malaysia sounds are used to alter participants emolional states. Tlw pulsing call of tile Golden-throated Barber alternates /)elween high and low notes and is rem iniscent oi a beating he,Jrt. Nearing tile bird Cillfing In tile forest invokes a feeling of l onging in the Temiar The ce remonial bamboo percussion instwment imitates this sound: two IJamboo tubes of differ en/lengths are struck ,,ltematel y against a l og: the silorler ruhe produces a higher frequency sound, the longer tuiJe a low er sound. Tl1e constant pulsing rh ythm l1rings ahout a state in the participants. t-lere female percussion ists (riglll) play bamboo-tube stampers during il trancing ceremony behind a male medium ( left). Inset s hows a Cold en-throated BariJet. Photo courtesy of Dr. Marina R osem,m. I


I H-18 Sandlf Podu/k.a, Marie Eckhardt, and Daniel Otis melodic sounds based on the sorrowfu l call of these birds Which of the many species of fruit-doves the weeper becomes depends on the degree of sadness (Feld 1990). Music and Dance of Western Cultures Western cultures also inmrporated birds into their music and dance in a variety of different ways, but to them birds were not as connected to the spiritual world a nd not as intertwined with their very existence. In western music an.d dance, especially that of Europeans and Americans as discussed here, birds served more as t h e subject of the music, or as part of the scenery, rather than be ing the very essence of it. Western music most often involves birds by using instruments or voices to imitate their sounds-the sound of the Europea n cuckoo (see below) is a f avorite subject as in the earliest known English sec ular piece the 13th century canon "Sumer is icumen in. But sometimes a music a l passage rs designed to create a general impression of a certain bird, as in The Peacoc k from Ravel' s Histoires Naturelles ." In this piece the peacock s m a jestic yet arrogant manner is portrayed, as well as the spreading of the greattail ( with opposing bla c k key glissandi on the piano ) and the harsh cry ( with dissonance } Contemporary com posers may use actual recorded bird sounds in their music; American composer )ames Fassett constructed his "Sy mphon y of Birds" entire l y from rec orded sounds. Respighi ll879-1936) was among t h e first to use recorded sound: his tone poem "The Pines of Rome" included a gramophone reco rding of nightinga l e song. In many compos itions, birds are the main focus but in others, birds are used to set the scene or indicat e time of day, part! cu larl y dawn o r dusk The familiar two note call of the Euras ian Common Cuckoo ( the model for the "cucko o clock ") is often used to seta p astoral scene (as in Beethoven's Sixth Symphony), since it wide l y recogn ized and easy to imitate Many birds besides the c u c koo have inspired composers throug h their sounds. Even thoug h their song is complex and difficult to repro duce faithfully, night ingales are often imitated in music as in Rameau' s '' A i r du Rossignol from his early 18th cent1,1ry opera Hipp o lyt e et Aricie. Doves are a nother favorite subject. Several species whose songs are less-often portrayed include the Scarl etTanager, in Dvorak s American String Quartet" and the Great Tit, in the 1st movement of Bruckner's Fourth Symphony. Bruckner strings together several Great Tit songs that sound very reali stic, but yet are well integrated with the music. Twentieth century French composer Ollvler Messiaen used the calls of 260 species throu ghout h i s works In "Reveille des O i seaux" h e used 21 species to represent a dawn chorus, a nd in "Des Canyons a ux Etoiles" (1974) he used 60 species from Hawaii a nd Utah Other birds have impressed co mposer s with the ir form or move ment. Flight a n inspiration to poet s and writers as well as composers, lends itsel f well fo musical interpretation. Benjamin Britten (1913-1976) used flute st.oc reateswallow flight in oneofhisairs,andpi cc olos forthe flight of the skyl ark in "A Midsummer Night's Dream. "Vaughan Williams also portrayed t he skylark' s flight i n 'The L a rk Ascendif)g!' Cornell ofOrnitholoBif


B irds and Humans: A Historical Perspective Th e rapid m ovement and twittering of go l dfinches is portrayed by V i vald i i n his f lu te concerto II Ga r d e ll ino." The gracefu l moveme n t of swa n s is another common subject of mus ical compositions most n otab l y in Tc h aikovs k y's ba l let "Swan Lake' ( Fig. H 1 8 ). The cour t s hip d i splay of t h e l y r ebi r d (see Fig 1 -88) even f i gu res in at l east one o n e-act ba l l et, "Th e Display," by Australian co mpose r Malco l m Wil l iamson (b. 1931) Th e Evolution of North Am erican T h e Y ears: From Aristotle to the 17th T h e first known scien tific l ist of birds was compiled by Aristot l e (384-322 B.C.). H is descr i p tion s of the habits of about 74 of t h e 170 species h e recorded were good eno u gh that we can recog nize t hese b i rds today. Pliny the E l de r (23-79 A.D.), a naturalist and a r m y officer, carr i ed on the tradition i n the 1 centur y A.D. with his Historia Naturalis, an encycloped i a of natu r al science that included birds Arc h aeolog ists have uncovered masterf u I pa i ntings ofbi rds i n the ruins of the ancient R oma n c ity of Pompeii destroyed in 79 A.D (Fig H -19) The Roman Empire fell i n 400 A .D., beginning the pe riod of i ntell ectual stagnation we now know as the Dark Ages a time when th e thr eat of t h e stake h ung over a ll who dared to question, r eason o r explo re. Altho u gh moralizing dis t orted much of the human knowledge existing a t th i s t i me birds were not forgotten. Am i d t h e bestiar ies and allegor ies of t h is e ra, one ve r y important book stands out: The Art of Falconry, by Frede rick II of H o h enstaufe n (11941250) w h o h ad the H19 I Figure H -18. London City B allet Pro duc t ion of Swan L ake: With their e legant forms and graceful movements birds have oft e n inspired western composers and chore ographers. The elegant mo tions of swans were the in s p i ration for T chaikovsky's well-known ballet Swan Lake. Photo by Robbi e ja c k I Corbis -------------------------Handbook of Bird B iolOfjlf


I H-20 Sandt/ Podulk.a, Marie Eckhardt, and Daniel Otis Fig ure H -19. Bird s in a Garden Mural from Pompe ii: Excavations at the cit y oi Pompeii, which was buried and yet preserved by the volcanic ertlpt ion of Vesuvius in 7911.0., have provided a window into ancient Roman life. Mural s from the many walled gardens show how important nature was t o the inhabitants. Shown are three panels las a composite image/ of one s u c h garden mural. In the left panel a jay is shown among plants such as lilies poppies moming glories, anrl a palm. The sm.111 center panel shows what has been described as a bustard. Tile right pilnel shows (from bottom to lop ) il Rock Partridg& and a male and female Eurasian Colden Oriole. Photos courtesy of Foto Foglia, from The Gardens of Pompeii by Wi111e lmina Feemster A. jashemski 1993. Published by Aristide D. Cavatzas, Nev., Rochelle New York. cou rage to carefu ll y analyze and experiment with the natural worl d. The book i n addition to details and directi ons for f alconry, gives much factua l information about birds and 1s the first scie ntific work known to conta i n bird illustrat i ons ( Fig H 20 ) Unti l nearly the end of the Dark Ages, s ubstantive material about b i rds had been scarce. W i t h the co m i ng of the Renaissance i n the 14th century and the invention of the printing press in 1448, a surge of interest in birds swept western Europe. I n t he n ex t two ce nturies with new opportuni t ies for inquiry and knowledge and for scientifi c and l itera r y expression, birds rece i ved thelr share of attention. T hree natura l history encyclopedias, published in Zurich Paris, and Bologna recorded cu r rent information about birds, including the ianciful as well as the factual. W ith the inte ll ectual expansion came the urge to broaden phys i cal horizons. Explorers set out from a ll parts of Europe. Many were b i rd watchers, albeit most l y for practical reasons. Navigators followed m i g r a t i n g bi rds to l and, or t he y took land birds 1-o sea and re l eased them hoping that the birds woul d lead them to new territories and new riches. The use of bir ds in nav i gation was not n ew. The Norse tale of the discovery of I ce l and in 874A.D described thepracticeofsendinga bird from s h ipboard to find land. Earl ier P I iny had written of the Cey l onese ----------------------Cornel L Laboratortt of'Omitholoatt


Birds and Httmans: A Historical Perspective doT ng the same in the S'h century B.C. The Dialogues of the Buddha mention it as being a habit of the seagoing merchants. T h e Polynesians may have been following the migration routes of birds possi b l y the Long-tailed K oel, when they j ourneyed to the Hawaiian Islands and New Zealand. Christopher Columhus c rossed one migrator y pathwa y of North Ameri can birds at just the right time and followed the ever -moving stream south to the Bahamas. In the journa l of his first voyage in 1492 h e wrote: October8-There were man y small/and -birds and /the sailors} took one which was flying to the south-west. There were jays, ducks, and a pelican. October 9 -A/1 night /the sailors/ heard h irds passing. For over 300 years after Columbus' notation in his diary-prob ably the first wri tten comment on North Ame r ican b irds-the knowl edge of the birds of this continent carne pie cemea l. The colonists and exp l ore rs, most of them untrained observers, spent more time in providing for their own surviva l than in noticing bi r ds. When they did observe birds, the y thoug h t oi them in terms of their native European species. The common name of the fam i l i ar American Robin is one ex ample. T h e early sett l e r s named i t after the smal ler, brighte r European Robin, which is a ver y different bird (Fig. H-21 ). The same is true for New World cuckoos, named after the Common Cuckoo of Europe. The American Redstart is also named after a simi l ar European species. Neve rth e less, t h ere a r e some early records: Cabeza d e Vaca, in F l o r ida in 1528, probably in the state's northwestern lake country, writes in his La Relacion ( 1 542 ) : "Geese i n great numbers. Ducks, mallards royal ducks, Flycatchers, night h e r o n s and partridges abo un d. We saw man y fal cons, gerfalcons, spar r owhawks, merlins." On the H andbook of Bird BiololJI1 H.21 Figure H-20. F alconers with F a lcons: Shown h ere is a drawing from The Al1 of Falconry b y Emperor Frederick If of Hohenstaufen Wrillen In 1 248, rile hook providerl detailed information on the husbandry oi falcons and the te ch niques ,md trapping s of falconry. This important earl y book provided much information abou t the natural history of game birds and is the first scientific known to contai n bird illustrations. I


Figure H 27. European an d A meric.1n Robins : E a rl y European settlers in North Ameri c a not well-versed in avi ,1n t.lxonomy, tend e d to name the h!rds they e n co unt e red a ft e r Old World specie s th; lflooked s imil ar. f-or inst, mce, the Am e ri c lltl Robin ( a ) was s o calle d bec.w s e its c hestnw-rerl bre a s t remind e d them of the f.9mi/iarEurop ean Robin from bac k hom e The European Robin (b ) is a co mpact c h a tlikebirc/, whkhsyst e n urtisl s c urrentl y pl,rce in the famil y Musci c ap i d.l e ( Ofd World ffy c ar chersl nr c American Robi n is a larger and mor e s tron g l y built bird i n the famil y Turrlldae ( thru shes) Photo a courtesy of{. R. Woodward I CL 0; photo b b) fohn a/o s i /VIREO. Pecos River in 1 535 apparent l y n eartheTexas/NewMexicobo rder, he feasted on quail brought in by nat ive archers fort he eveningmea l. Cas tenada, wri ting of the Coronado expedition of1541 to 1542 observed tu r keys and tame eagles i n Ari zona a n d cranes, w il d geese crows, and blackbirds in New Mexico, r eports that must surely be amo n g the first ornitho l og i cal observations made in the contin e nt a l United States. As e arly as 1585, John White, a member of Sir Waller Ral eigh's second expedit i on to Roanoke Island, Virg in ia, painted a ser ies of wate r colors of Ameri can birds. The paint ings, well drawn accurate!} tinted, and more import ant the results of firsth and observations were first pub lish e d in lSYO in de Bry's Virginia ; t h ey may be enjoyed today in all theirglowingcol ors in Stefan Lor ant s TheNewWorld ( 1 946 ) Between 1630 and 1646 William Bradfo r d, governor of the P lymouth colony, wrote that wild tur keys and waterfow l had been abundant i n 1 621 but that waterfow l decreased the r eafter. In 1674, John Josselyn noted thaJ y ou n g turkeys were once ab u ndant i n the woods But ... the Englis h and t h e Indi a n s {have I now destroyed th e breed so that t is ver y rare to meet with a wild turk i e i n the woods." Although the explorers and col onis t s sent home" living and dead specimens of birds du r ing this period, the i nvestigation of Ame ri ca n bird life h ad to wait for the furt her deve lopment of sc i ence in Europe In 1678 appeared The Ornithology of Fran cis Willughby, by Willughby and his friend John Ray. This publicati on was a sc i entific l andma rk, the first major work based o n careful observation of both the structu res a.nd habits of birds. The a.uth ors adopted the most valid c l assificat i o n and species concepts of the day and the Il l ustrations were far more ac c u rate than any previously printed. I n preparing the illustratio ns, the artists used engraved plates that p ermitted far more d e l i c a cy of detail than the woodcuts used previously in t h e early en cycloped ias (Fig. H-22 ). Cornell L ahorato nt of'Omitho lotJlt


Birds and Humans: A Historical Perspective The 18th CenturLf With the 18th century carne important American scientific events. From 1712 to 1719 and 1722 to 1726, Mark Catesby, a young Englishman, roarned the shores and woods of the south eastern colonies and islands His. ambitious plan was to paint, de scribe, and name every bird, and other vertebrates as wei I that occurred between the 30th and 45th deg rees of latitude.'' Short of funds he pub I ished his book in sections fro m 173 1 to 1743 Physically the compl ete volume, The Natural History of Carolina Florida and the Ba hama Islands I s l uxurlous, nearly 14 by 20 inches (35 by 50 em) in s ize, w ith 220 handpainted engravings, all but two of which Catesby did himself ( Fig H-23). Scientifica lly, the illustrations and the accompanying discussions earned for the authorthe well-deserved title Founder of American Ornithology.' Catesby for h is time was r emarkably unbiased and insisted on verify1ng hearsay with pe r sona l obser vation His drawings and descriptions were the basis for over one-third of the American bird s t h at Linnaeus later described. Artisti cally, Catesby provided s evera I innovations: he painted livin g birds, naturally posed in their native habitats. He also conside r ed shading and composition using bold pat terns of light and dark in some of his paint ings. The best were uns urpassed for over 1 00 years. In 1758, Linnaeus published his Systema Naturae, whi ch laid the groundwork for modern binomial nomenclature and kindled in travelers th e desire to find and n ame different kinds of organisms including birds Specimens of p l ants and a nimals flooded into Europe from the New World. Aviaries with pet birds from the colonies were much in vogue. In England, George Edwards, Thomas Penn a nt and John Latham, important "a rm chair" ornithol ogists, compil ed great volumes on birds from specimens of species the y never saw alive. Their com ments, however based on second-or thir d-hand information were not always reliable. Edwards A Natural History of Birds ( 1743 1751 ) was worldwide i n scope; Pennant's Arctic Zoology(1 784 1 785) dea l t Ha11dbook of Bird Biolofjt( Figure H-22. Waterfowl from The Orni thology ofFrancis Willughby! Willughb y was a n t;nglish natur

I H.24 Sand!f Podu/ka, Marie Eckhardt and Daniel Otis HISTORY Of BRITISH BIRDSo THE FIGURES NGRAVED ON WOOD BY 'l' BEWICK. PART I COXTAJNlNO TUC-HJSTORT AND Dl!SC.Ril'TJON OF LAND BIRDS. NEWCASTLJ): l' .. l)ITED U\" IDWAiii.D WAL"--2ft1 f Oit. f 8tc\\'J(tc: : 5 01..0 B Y IJI)I1 AWJJ LONGMAN .H:O CO. l.O S'U0 1f. Figure H-24 Title Page and llfuslrat.ions from A History of British Birds, b y nromas Bewick: In t/Je 1790s. B ewick d eve l oped a new printing metl1od for illustrations. H e use d end-grain woodcuts, elimina t irtg the n ee d for expe nsive cop per plates ye t allow ing fine detail His 1809 A Hlstor y ol Bri t is h Birds was the first bird book readil y availabl e to the general public. The illu scraiions show, from top co b ottom, Cqmm o n Cuc koo ( the mod e l v o i c e (or the popular c u c koo clock). European Coldfinc h and Northem Lapwing ( called in the ori ginal b y its co lloquia/name "Pee-Wit). Cornell L.aboratorLj of Omitholo911


Birds and Hu111ans: A Historical Perspective primarily with North American birds ; and Latham's A General Histor y of Birds ('1821182/3) included t he first attempt to systemat ically treat all the birds of the world. In the 1790s, Thomas Bewi c k devised a new method for producing illustrations by using end-gra i n woodcuts that i n c r eased detail to a degree formerl y impossib l e in wood and eliminated the need for cost l y copper engravings. His A History of British Birds (1809) was t h e first well-illustrated bird book available to e veryone (Fig H-24). In 1791 appeared Travels Through North and South Carolina b y William Bartram a professional bird watcher and so n of a famous Philadelphia nat u ral ist. Although Bartram's notes on birds and thei r hab its were at times mor e poetic than sc i e nti fic, he stands out as one of the f i rst Ameri cans to con t ribute to ornithologi c al knowledge. Loui sV i eillot, a Fre n c hman was the first t o point out variat i on s in plumag e w ith season and sex in his L 'Histoire Naturelle des Oiseau x d e L Ameriqu e S eptentrionale ( 1807). j ohn Abbot a n Englishman work e d f rom 1 804 t o 18 2 7 on severa l drafts of a manuscriptthat conta in ed notes on life hi sto ries and illustrative paintings of the birds of Geor g ia. Unfortun a tel y, non e oi h i s work has ever been published. In the New World through the 1 8th and i nto t h e 19th centuries, most people still recove r i n g from the Ameri ca n R ev o l ution and inte n t on establishing a new nation were co ncern e d w ith more practi ca l affa irs than studies of bird s A l mos t from the beginnin g, howe v e r t h e eagle in one fo rm or a noth e r was a symbo l of the Unite d States. The two-headed eagle first proposed as th e nation a l sy mbol of the Unite d State s in 1776, r esemb l ed the imp e rial G e rman eag le and was not ac cepted. Cong ress considered a numbe r of oth e r de s i g n s and fina ll y in 1 782, chose a c r ested, stylized eagle for th e offi c ial seal. Sin ce that time, minor a l terati o n s in the seal have i ncluded t h e el imination of the bir d's crest and modifica t ions in form and co lor so tha t the bird on t h e seal tod ay mor e closely resembles the Bald Eagle than did the original (Fig. H 25 ). The selec tion of the Bal d Eagl e as the Ame rican sy mbol did not please everyone. Benjami n F r anklin thou ght t h at the eag l e does not get his living hon estly ... too l azy to fish for h i mself, h e wa t ches the la bor of the fish i ng h awk, a n d when thatdiligentbird h a s at l e ngth taken a iish ... t h e bald eagle pu rsues him and take s it from him.'' Franklin much preferred the Wild Turkey, which, t hough a litt l e vain and silly," was "a bird of co urage.' Todayornithologists try t o avo id judging bir ds by human standards of morali ty The 19th In a century that i nc lude d man y g ift ed liter a r y scienti sts," Henry David T horeau was perhaps the finest. Although h i s works w e r e oft e n Hamlhook of Bird Bioi091f H251 Figu re H -25. Great Seal of th e Un i ted Stales: T11e e,lgl c has been official symbo l of th e United States si11ce the na r fon beginning. It s inrm h nwevet; ha s varied uver thft ) 'ears. In 1 776, cong ress rejec t ed the t wo-h eaded bird proposed J S ril e 1 M tiona/ S) mbol tina II ) acce ptin g a crested. s t ) lize d eagle in 7 782. S in ce th e n the c re s t has been omi tt e d ,,nd rhe s h ape ,mrf rolor moc!IJ/ed so t hat t orlay's sy mbol more close / ) represents rJn ac:ttra/ Bald Eagle. The eagle clut c hes Mtows Jnd an olive br,mch-symb o ls, resptJctivel y1 of war ,1nd pea cf'. Tf; e sryt e of eagl e cu rrentl y userl i n the Great Seal, as shown here, was Jlrst a d opted aro und 1885. n,e Great Seal is u sed in mtmPmus offi6. 1 1 ways, s u c/ 1

H 26 Fi g ure H-26. john Burrou ghs and )olin Muir: As ,m essayist and naturalist john Burroughs inspired a generation or American ,md comervalionists in the late /9tll and early 20th centuries. Nicknam'-'d "John 0' Birds," Burroughs ( tight ) imbued his bird vrit ings with emotional and poet i c descrip tions, while excel/em birding skills assured the accuracy oi hi s observa(ions. jo/mA fuir ( left), shown here visiting Bur roughs for the Iauer'> 75/h birthda y cele bration was a naturalist conserv,l/io nist. and bird enthusiast from the western Uni t ed 51,1/es. Nicknamed "John 0 (vfountain s," Muir bec,1me well known as a proponent of creating national parks and conserving forests. Photo courtesy of Libra f) of Congress. emotiona l and philosophical he wa.s an exceeding l y acute and ac curate observer, and he is cons i dered b y many to be the firsltnrl y great American nature writer. Thoreau had little interest in what we would ca ll l aboratory studies ofbirds.ln his words, ornithology at ils best was a "window opened wide to nature. In the last half of the 1 9th century, J o hn Burroughs (Fig. H 26) a ser ious studen t of birds with a critical and inquiring mind, was perhaps the most widely read and l oved of the nature writers i n spite of the fact that h e did not hesitate to personalize birds as in his "Wake Robin." The John Bur r o u ghs Society, established in his hl)nor, continues today and eac h yea r h onors the author of t he most oul standing nature book publi shed in the preced i ng year. At the end of t h e 19th cen tur y thre e aulhors of buoks on b i rds s tand out. l ohn Muir (See Fig. 1-1-26), naturalist. conservationist and a l so b i rd enthusiast wrote about the Water-Ouzel in his book The Mountains of California. The approach of Bradford Torrey, writer and ornithol ogist var ied from the an thropomorphic in Birds in the Bvsh to a detailed study of species in The Foot-Path Way. Fran k Bo lles h ad a brief ca r eer but showed great promise in his last book, At !he North of Bearcamp Water The nat u re writ ers of the '19th cen tur y wrote c h a rming, pleasant books for

Birds and Humans: A Historical Perspective Young People, St. Nicholas, and The Youth's Companion, entreated thei r young reade r s to protect birds. Birds, a maga zi ne started in 1 896, served as a guide to natur e e ducation in t h e schoo ls, as did four books by women: The First Book of Birds by Olive Thorne Miller, Birds ofV/IIageand Fie ld by F l orenceA. Merri am, Cit izen Birdby Mabe l Osgood Wrigh t and How to Attract Birds by Neltje Blanchan. Meanwh ile, the ornitho l ogists were ac cum ul ating, assi mila ting, and beginn i ng to publish vast amounts of information. Lacking modern photography, the arti.sts amo ng them portra yed the species as they saw them. A l e)CanderWi lson poet, artist. a nd weaver, arr i ved i n Amer i ca f rom Scotland in 1794 a n d within 14 years had compl eted the first vo l ume in a projected 1 0-volume work on America n bird s that would earn fo r him the title, F ather of American Ornithol ogy Shor t of funds a nd forced to depend on an inadequate number of subscribers forthe entire set of American Orni thology, Wil son wa l ked throu gh New England a n d sou th along th e coast to Geo r gia, carrying Volume I ( 1808 ) an d col l ecti ng, painting and stu dyi n g b irds as well asseekingsubscribers. H e took a second wa l k westwa r d down th e Ohi o and Mississippi Rivers to Natchez, a nd then east across the country to Phil adelph ia. H e fo und s upport for this proj ec t in Phi l adelphia: William Bar tram a n d Charles Wil son Peal e e n couraged a nd he l ped him; Peale's m u seum supp l i ed him w ith speci m e ns. H e r emained n ear Phila delphia for the rest of his life, wri ting painting, an d collecting. When h e died in 1813 at the age of 471 h e had compl eted eight volumes. The ninth edited by Geo r ge Ord, was published i n 1814. The nine vo l umes th at appeared in just over six years con t ai n ed i ll ustrations of 320 species-39 that h ad never been i ll ustrated be fore-on 76 full-page engravings (fig. H-27). L ooki ngat them today we admire the skillfu l drawing and fo r get, iiwecan, the awkwardness caused by crowdi n g too many b i rds on one plate as .1n econo m y mea sure. T h e text raised the level of ornithology by including accurate first-hand observations, measurements of specimens, and n otes on the fresh co l o r s of the bill, irises, and other soil parts tha t f ade quickly once the bird is d ead. The paintings of J ohn lames Audubon howeve r were soon to sur pass thoseofWilson eve n though Wil son may have insp ired Audubon to publish his work. The two men met In Louisville Kentucky a n d r eports of this meeting are numerous and conflict i ng. Later there was ill feeli ng between the two a rtists. Handbook of Brrd Biolo8'1 H .27 ... ... .... ,, Figur e H -27. Plate from American Orni tho logy by Alex a nder Wilson : This plate /rom Volume I of the nine volume seL demonstrates the crowding o( seveml species on ,J single plate as a of reducing publishing costs. Shown here are Pine Siskin Rose-breasted Grosbeak, Black-throated Green W,1rbler, Yellow rumped ll\lariJ/er, Cerulean Warbler. Blu eheaded Vireo, Note tiM/ some of these species names have changed sine@ this book was published.


H Fi gure H -28. O sprey by j o hn james Audubo n : Born in the Caribbe an in 1785 and raised in France Audubon began paint ins birds as a c hi/rl. His dra matic paillfings of birds from th e New World were first published by an English engraver, Havells of London. Between I 827 and 1838 Havel/5 produced the (ow elephanl-iolio of Tht> B irds of America, c ontaining a total of 435 plates using the technique or' aqua tinted coppe r engraving T ypical of this ilrtist's portrayal oi ,Je t ion is th is Ospre y carrvi nfl its c

Birds and Humans: A Historical Per;-pective was the case with the Lewis and Clark E x pedition. Without a trained zoologist to g uide them, the cap t ains relied on designations in common use i n the East, naming new birds in terms of species with which they were familiar. As a result, they called the Californ i a Quail "a bird of the qua il kind and McCown's Longspur a ''small bird resemb ling a lark, b u t the vivi d descriptions of t he two species leave little doubt about their identity. So well and in such detail did Lew i s and Clark r ecord the i r observations of new species that later ornitho l ogists were able to place the p r oper techni cal names with these descriptions Nevertheless, very little ornitho l ogical renown ha s been bestowed on the captai n s even though their ex pedition returned with obser vat i o n s of about 130 birds many s uch as the Clark s Grebe, T undra Swan Lewis Woodpecker, Sage Grouse, B r oad-ta il ed Hummi ngbird and Western Tanager, new to science_ True "Clark's Grebe," "Cl ark's Nutcracker," and"Lewis' Woodpecker" memorialize their names but t h ese ascrlptions reveal little of their achievement. One searches the lists of alternative common names in vain for mention of lewis and Clark. The American Ornithol ogists' Union Check-list, d.t least refers to two names t h e captains fir s t used, the "Whls t l fng Swan'' (Tundra Swan) and the P rairie Hen" ( Sharp-tailed Grouse ) Later n at uralists generousl y avai led themselves of the captains' patient labors, almost always without a shred of acknowledgment. Some expeditions were fortunate i n havi n g orni tholog ists whose careful r ecords contributed a g r eat dea l to the expedition s data. Tit i a n Handbook of Bird Bioloatt H Fi gure H-29. S p otte d Forkt ails from B irds of A s i a b y john Could: Author of man y books and .sci enrilic article), English omit hol ogis t and painter John Could !7804-t88/ ) aspired to illustrate all the birds oi the world. H e even tual/)' published 41 folio volumes in which the illustrations were reproduced by the relatively new method of lithography. /-lis artistic wife contributed greatly by handling the technical asped5 of the lithographic process, and severo'!/ other artists contributed plates. monographic works included the birds of Australia, Asia, Europe, Great Britain and New Guinea, and his Monograp h of theTr ochilidae ( hummingbird (amity) ( 184 9 -1867/ is co n sidered his master piEce.


H Figure H-3(/. Smit h sonian Instituti on Bird Callery: n1is I 885 photo,r;rat:Jh de pictstaxidetmic mounts and study skins atop a Jongcasenfspec imen rlrawersat the Smithsonian Institution in Washington, D. C. Many natuml history centered on bird collections Wt>re estab lished in the United States during the I 8005. Negative number 96-3532. Smltl1sani,1n Institution Bird CiJIIery, I 885. Smithsonian lnst iltllion Arr:hives, Record Unit 7006, Alexander Wetmore P.1per'$, Box: 19 S Sa11d1f Podulka Marie Eckhardt. and Daniel Otis Peal e accompanied the Long Expedition of 1819 1820, painted sev eral birds, and n o doubt l aid the groundwo rk for hi s later illustrations in Charles Luc ien Bonaparte's ext ension of Wilson's American Omitholosy, published in four volumes in 1825. F r om Peale's brush came all b ut one of the lllustrations in Volume One i n clud in g the plate of Say's Phoebe, first described by his fellow t r aveler o n the Long Expe dition, Dr. Thomas Say. Peal e also went o n the Wilkes Expedition of 1838-1842 from Virginia to Rio d e J aneiro, a r ound Cape Horn to Peru, Antarctica New Zealand, the northwestern Un ited States, the Philippines and back to New York by way oftheCapeofGood Hope. The data from this voyage, compiled and edited by ornitho.logists who had not made the journey, became the first m ajo r publication on birds sponsored by the government. j ohn Cassin compi led several of the vo lumes, among them Illustrations of the Birds of California, Texas, Oregon, British and Russian America ... and a General S y nopsis of North Ame rican Ornithology ( 1 853-1856). Several naturalist s joined the railroud expl o r ations t hat moved west from the Mississippi River to the Pacific bet\.veen 1853 and 1 856. Their data, added to i n formatio n from private co ll ections, were edited chi efly by Spencer Fullerton Baird assistan t secretar y of the Smithson ian Institution, and becam e the second part of the ninth vol ume of Reports of Explorations and Surveys to Ascertain the Most Practicable and Economical Rout e for a Railroad from the Mississippi River to the Pacific Ocean ( 1858), o n e of the most importa n t federal pub li cations of the century. This purely ornithological section, known as Baird's Ge n eral R eport for politica l reasons, in cluded desc riptions of 738 species of birds and was the first book on t h e bi rds of the entir e continenta l United States. Later the section was reissued private l y as The Birds of North Ame rica ( 1860). Although the infor mation was more detalled and accurate than any yet published, the book lacked the charm a nd spontaneity of the works by Wilson and Audubon. Natura l history inventories and the co l lection of natura l history objects ( including birds and t h e i r eggs) led to the creation of many natura l h i story museums in the U nited States in the '1800s. Among these were the Amer ican Museum o f Nat ural History in New York City; the United States Natio n a l Museum (Smithsoni a n ) i n Washington D. C. ( F ig. H-30); the Academy of Natu ral Sciences in Philadelphia; t h e Museum of Comparative Zoology in Cambridge, Massachusetts; the Field Mus e um of Chicago; and the Carneg i e Museum In Pittsburgh. Although there were many private collecto rs, these earl y museums soon became centers for the study of birds. In t h e 19 '" century, ornitho logy was sti II a descriptive sci ence. No formal academic training was avail able and the few fortunate men em---------------------------------Cornell Laboratont of Omitholoatt


Birds and Humans: A Historical Perspective p l oyed as "professiona l orni thologists wer e among th e directors and curato r s of the ear l y n atural hi s tory museums. They held no degrees in orn i t h ology, a n d in fact, many h ad n o college educa tion atall.ln stead, they were eit h er self-ta ught or appre n ticed und er someone knowl edgeable in the fie l d. Expertise was gai ned by f i rst h and expe ri ence in the field, collecting and obse r ving birds. A personal co l l ection of bird specimens was consid ered essential for those ser i ous about bird study. Along with the professionals ,'' there was a well-to-do upper class w h o enjoyed l earning abou t birds and had th e f i nan c ial means t o spend time in the f i e l d creating their own persona l collections. T h ey also re l i ed heavil y o n the work of collectors, taxidermists, and sport hunter s to expa n d their collecti ons of bird specime n s The p rofe ssiona l ornithologists affi li ated with the early Ameri can museums p l ayed a cri t ica l role i n advancing ornith ology. Notable among this g roup wer e Robert Ridgway curator of b i rds from abou t 1881 u ntil his death in 1929 at the Un i te d States Nationa l Museum in Washington D. C., and Frank Chapma n cura t o r of b i rds at the Ameri can Museum of Natural H is tory i n New York Oty. Robert Ridgway (1850-1929), a founder and president of the American Ornithologi s t s' Union, servedascuratorofbirdsatthe Uni ted States National Museum (USNM) foroverSOyears was theauthoroftwo i mportant works in ornithol ogy: A Manual of North American Birds ( 1 887) and a series of volumes known as Birds of North arid Middle America (1901-1919). Frank C h apman (1864-1945), was considered th e Dean of Ame r i can Ornithology (Fig H -31). H e was a p i oneer in bird photography a lecturer and a prolifi c writer w i th over 225 a r ticles and 17 books. His Handbook of Birds of Eastern North America published ln 1895 was the most widely u sed gu id e of its time. By the late 1800s, regiona l bird clubs, societ ies, and organiz a ti ons were sp routi ng up all over the country, and some r ema i n act ive to this clay. T h e N u ttall Ornithologica l Club, crea t ed in the early 1870s was thefirstornithologi ca l club in the United Stales. Th e requireme nts for joining th i s g roup wer e minimill-you hild to be male and h ave a special interest in bfrds. Theclubsoon inclu ded a diversegroupofmen, of Bird BioloBtJ H Figure H-31. Frank Chapman: Although he had no formal ornithological/raining, Chapman was a g ifted writer, l ectu rer, and scientist. l-Ie served as t h e curator of birds iliLheAmerican Museum ofNawra l Histo''Y < l nd bridged the gap between amateu r a nd professional omithofo,IJists with hundreds of articles, 1 7 books, and a popular magazine Bird-Lore, which eventliallybecameA udubon magazine. Negative number 1 2930 co urtesy of the Department of Library Servias, Amer lean Museum oi'Na tl/ral History.


H .J2 Figure H-32. Theodore Roose1 ell and John Muir: This photo, circ a 7906, s ho ws two pioneers in Califurnia's \''osemile \I

Birds and Huma/15: A Historical Perspective birds and mamma ls. This later be came the U. S. Fish and Wildlife Service within the Department of the Interior. From the work of one committee, t h e foundation for a federal agency with a mandate at least partly in ornithology was created, and the fi rst study of b i rds usin g data collected from a l arge number of vo l unteer pa rticipants-Merriam's bird m i gratio n study was carried out. The o t her origina l AOU committee, t he Committee on Clas sification and Nomenclature, developed t h e fi r st "Code of Nomenclature"-a standardized list of common and scient i fic names for North American birds. This was a s i gnificant step because before the "Code" the r e were two cornpeting I ists of North American b irds. Stan da rdizing bi r d n ames was essentia l for any accurate inventory of bird d i stributio ns. The Committee on Classifica tion and Nomenclature has a l so been responsible for determining which g r oups of birds cons t i ture s pe c ies : whether c ertai n groups traditionally c onsidered sepa r ate species should b e put together as one (lumped) or whet her certain species should be divided into several (split ) These issues are often (ier ce ly debated Each year at t he annua l AOU meeting th i s commi ttee r e views new resear ch concerning the taxonomy o i North American birds, determin i ng whi ch spec ies to spl i t and whic h to lump, as well as d eciding on a n y name c h anges f o r spec ies. T h e AOU r eg ularly pub lishes u pdates of the Check -list of North Amer ican B i rds. Anyon e who thinks taxonom y is a stagnant science shou l d c onsider t hat there w er e over ISO c hanges between the sixth edition published in 1983 and the seve n th edition p u b l i s h ed in 1998. By the late 1 800s, there was growing concern over declines of many bird spec ies. H abitat dest ructi on and market hunting for p l umes and meat had take n the i r toll on a numbe r ofspecies, includi n g the now extinct Passenger Pigeon and Carolina Parakeet. TheAOU Comm i ltee on Protection of North Ame r ican Bi r ds1 created in 1884, played an i m portant role in foster i ng bird protEction in A m erica. Their f i r s t priority was to a l e r t the public to t h e decl i ne of b i r ds. T hey also proposed l eg islat i o n which was pas$ed in some states making it ill egal for a n yo n e to ki l l purc hase or se l l non-game b i rds o r their nests and eggs. The f ir s t Audubo n Movem e nt At the same time the AOU was publish i ng its first bu ll eti n on bird p r otection, George Bi r d Grinnell was c reat ing the first Audubon Soc i ety Editorinc h ief of Forest and Stream, and at one time a student of L ucy Audubon1 the widow of john James Audubon Grinnell was a l e ading voice in condemning t h e com m ercia l exploita t ion of wild life He was a l so one of t h e foundi n g members oftheAOU. GrinneiJis l o ng-term goal was to create a national society orga nize d i nto loca l chap t ers and he nam e d his new organization afte r the l egendary bir d artis t J oh n James Audubon. Grinnell's Audubon Society e n joyed earl y success, but unfortu natel y it wasn t sustained. By 1 888 the work of both th e AOU bird protection commi ttee and Grinnell's Audubon Society had stalled. Although shor t -lived, Grinnell's Audubon Soc i ety stre ngthe n ed the public's growing c o n ce r n about bird destruct i on a n d established a public arm to the bird protection moveme n t. Handbook of Bird H U S. J\GRJCULTURE. lN,' UIOll iJ, fiiiSIT1h 1 &CIIf r &ru.t:n) :t, HIH'CJUT BIRD M1GRATJON VALLEY tUUH""01'q>l'll .... ,. .... ........ ..... 1(. i", h U F igure H -33. Bird Mig ration R e p o r t : Shown here is a r e port on bird mi g r a tion from the U. 5. Departm e nt or' Agricul ture's D Msiort oi Economic O rni-th o l ogy. Throug h the urging oi C. /-/art Mer r ia m .wd t h e American Orn i-tho logist s' Uni o n congress ii!uthorited the l is hment o; t h e Division ofEc:on omic Or nith o logy in 1885. Although the original int e nt of the was to stud y the effects of birds o n agricultttrai produ c tion over the years rhe sc:ope broadene d to in clude the gen er.11 s tucl y of bird s B y 1896 the Division of Economi c Ornitholog y hJd become the U. 5. 8/o lo g ic:al Survey. which eventuilfl) became the U.S. Fislt a nd Wildlife Service 1ithin the D epartment of the tncerlor.


Sandlf Podulka, Marie Eckhardt. and Dani e l O tis Women in i tially exclu ded from the m a le-dom i nated ''professio n a l organiza ti o n s," were i n strume ntal in populari z in g the st u dy of birds a nd b ird p r o tecti o n. In 1886 F l o r e nce Merri;J.m (th e s ister of C. H a rt Merriam ) c reated a l oca l Audubon chapter w hil e s h e was a student at S mith Co ll ege. In 1 887 she began w ritin g a ser ies of art icle s ("Hints to Audubon Workers: Fifty Birds and How to Know The m ") for Grinnell's Audubon Magazine. At the conclu slo n of the series in 1888, she incl uded a f i e l d key incorporating color bill s hape, song type, behavior h ab i ta t preference and nesting habits as characters to he l p id e nti fy the fifty spec ies. In 1889 she published her f irst book, Birds Through an Opera Class, in w hi c h she expa nd ed her field key to seventy spec ies. It became a bestseller, in spi rin g thousa nd s t o t ake up bird watching. Many s imilar publicati ons by other aut h o r s soon followed. The Second Audubon Movem ent The bird protection movement was r evila l lzed in 1896 by two Boston women H a rri e t Hemenway a nd her cousin Minna H all, w h o were instrumenta l in creating the M assachusetts Audubon Society. I nspired by horrific accou nt s of b irds s l a u g h tered only to adorn women's appa r el the mission of the organ iz a tion was to discourage the use of feat hers fo r ornamen t atio n an d to promo t e the protect ion of birds. Concer n ed people in ot h e r s t a tes soo n estab lish e d simi l ar o rganizat ions. At a bout t h e same time the AOU bir d protection committee was stre ngth ened as William Dutcher became its chai r man. Dutcher was d edicated to eslil bl i shing state Audubon soc ieties and promoting bird protection thr ough public educa t ion. In 1 905, Dutcher created the National Association of Audubon Societies Havin g a nati o nal as sociat i on relieved the AOU o f much of its r ole in bird protection-a role that was increasing l y divisive amo n g its members, as many were actively co ll ec tin g birds. The AOU did no t r ev ive its bird protection ac ti vities unti I 1930. Meanwhile, the American Museum of Natura l History was pro foundly affectin g ornit hology. Frank C h apman, first hired by the mu seum in 1888, eventually became curator and served in that capac ity until 1945. A l though h e had no forma ed ucation C h ap m a n was a gifted writer l ec turer, a nd scientist (see Fig H-31 ) In a fie ld th at was becoming i n creasi n g l y divided, Chapma n for m ed a b r idge between the professional and amateur. H e c reated the popular bird m agazi n e Bird-Lore in 1898, in part to s vppternen t h i s income J but also to assist t h e AOU bird protec tion commi tte e in distributing information on bird prote c tion to t h e public. (Fig. H-34). Bird-Lore introduced a new ge n era tion of people to the s tud y of birds and it serv ed as t h e voice o f the emerg in g Natio na l Association of Audubon Societ ies The Na t i o n a l A u d ub on Society assumed the publ ication of BirdLoreln 1941 renaming i t Aud ubon Maga2.lne. In 1 953, the n ame was s hort ened to Audubon, the publication familiar to us today. During the last quarter o f the 1 9'hcent ury, orni thologica l pub li ca lions began to pro I i fer ate+ Sorne wer e sponso r ed by s t ate gove rnments, Cornell Laborat ortt ofOrnitlwloalf


B i rds and Hu111ans; A H istorica l Perspective b u t many othe r s were prod u ced by pri vate publis hers. The l i te r at ure i n cl u ded state and regio nal works o n bir ds and, most importa n tly, Elliot Coues' Key to North American B irds, th e class i c that f irst invoduced ornithology to many thousands of people ( Fi g H-35). The 20tl' and the ExpandinB Role of the Bird W atcher The growi n g num ber of bir d wa t chers in the l ate '191 h century p r esented bot h challe nges and opportun it ies to p r ofessiona l ornith o lo gists. As bird collect in g became mor e restricted, ma n y ornith o l ogica l societies focused mor e on fie l d stu d ies and cooperative researc h especially i n the areas of geog r ap h ica l distr ibuti o n migr atio n and life h i story studies. Lynds jones, a foundi n g me m ber of the Wil son Ornith o l ogical Society, and h is studen t William Dawson, advocated systema t ical l y keep i ng deta i led checklists of birds observed at different l ocations a n d times of the year. T h e val ue of s u ch lists, t h ey lobbied, was t hat t h ey could be used to esti m ate bird abundance. Dawson and jones soon had h u n dreds of observers competing to compile t h e l on gest lists. Gett i ng out into the f i e l d to coun t bir ds replaced collecting in n ume r ous ways, providi ngmanyofthesame benefits w i thout k i ll ing b irds. T h e compet i tive aspec t a lso att r acted the interest of a w h o l e new breed of bird watchers. Observe r s wer e encouraged to subm it their lists fo r p u blicatio n i n t h e Wilson B u l l etin the journal of the Wil son Ornith o l og i cal Soc iety. T he i dea oi count i ng birds inspi r ed F r an k C h apman t o p r opose a Christmas B ird Count i n 1900. C h apma n encouraged people to count birds I n stead oi participating i n the t raditional Christmas Day H andbook of B i r d H.5 Fig ure H-34 Birdl o re : One of the first popular bird Bird Lore be gun in 1898 by Frank Chapman, intra duc e d a new generation of people to the stud y oi birds and set ved as the voice of the Nat irma/ Associatio n oti\udubon So cieties Bi r d -lure was renamed Audubon Magazine in t941, and the name was s hortened to Audubon in t953. Today, Audubon serves a s tile prim < ll ')' publi c ati o n oft he National Audubon Snt.iet)l. oi the National Audubon Soc i etv. Figure H-35. Ellio t C o ues: Coue s Key 10 Norlh Amer i can Birds was the most influe nti a l of the numerou s ornithologi cal publications that prolif erated during the late 19th c entury. Its two illustrated v olume s c ontained im'or mation about the structure and classific ation of living and fossil birds as well as a manu,1l on colle cting, preparing, and preserving bird specimens.


H-36 Figure H-36. Art hu r Cleveland Bent: During th( early I '1005, A C. R ent pmduterl a serie;, o/ texts Oil thr/ite l>istories of man y groups ufiJinl> $1Jth Js the l ife 1-tislnricso( NurlhAmeric;,n Bi< ls<>f Prel and the Ule 1-tisloric:s <)I North American '\hnre l 1irds. Bent nhtilinod mud> ot the inlormaticm for Iu s from the newl y loundcd U. 5. Biologiri!l SurVC)' ant/ h y cn trr.>51mnrling with utlwr keen IJirrlwat hers Tn tl1is day, Rent's .m used hr hirdLrs ilnd ornithologists ns .i source uf lift.' histnr y tn/()l'lll.JI inn. Photu LvUrlesy nl D I Cat risnn. Sandt/ Podu/ka, Marie Eck}wrdt and Danie l Oti s Hunt, promising tu pub li s h the result s in Bird-Lore. From thi s modest beginning the Bird Coun t has become a major orn ith o logical tr adit i on, co ll tcti n g val u,1bl e informatio n on bird ab und ance thr o u g h out the United S tates lu this day. By the ear l y 1900s, the U 5. Biological Survey had an enormo u s a m ou nt of d ill,, on I >ird mi gration i n additio n to data o n bird abundance from the surveys. T hi s information was used L>y 1\. C. B e nt to comp ir e hi s m onume nt a l Life 1/istorTes series ( Fi g H 36 ) a nd by t h e AOU t o prepa r e their C h eck-lists of North Amer ican B i rds. Wh i l e the U.S. Bio l ogica l Survey's census programs waxed and waned, the Nat iona l Audubon Society began its own spring co unt in 1937, the ''Breedin g Bird Census." Still h eld each j une throu g h out the U n ited States, the Breeding Bird Census i s a major effo 1 1 to cou nt birds in the breeding season. Bird banding was quickly gainin g m o m e ntum as people reali zed it was usefu I for s tud yi n g bird movements. All he 1 909 AOU meet i ng, band in g o rganized the Nationa l B1rd Banding Associa t ion ( NBBA), w h ic h was admini s t e r Ptl through sever al d i fferen t orga nizati o n s before its demise. In lb wake, regio n<1l organizations we r e forme d t o f ill the voi d : th e New Engl and Bird Bandin g AssociatTon in 1 922 (renamed the North American Bird BandingAssoc i at i o n i n 1924), the Inl and Bird Banding Associ atio n ( I rJ22),t h e Eastern Bird Banding Association ( 1921), and the Western B ird Banding Associat i on ( 1 925) As a resul t rJf the growth of bi r d bc1nding i n the 1920s a n d 'JOs, the U.S Bio l ogical S ur vey ( now the Biological Resources Division of U. 5 Geo l og i cal S urvey) began to coo r dinate b a nrl ing act ivities. This organizatio n a nd i t s Can<1dian counterrMt have overseen the activities of de dicated North American bird banders ever since. The Devel opment o f t h e Field Gu id e Wh i I e bird watchers we r e amassin g a II ki nels of i n forma lion a bou l birds, the scient ifi c co mmunity was becoming increasing l y s k e pt ical abo u t the accuracy oi many reports With n o specim e n s to back them up, reports n( quest i onahle birds were hard to verify and t hu s we r e of little scientific value. Yet,

Birds and Humans: A Historical Perspective a system of a rr ows to i ndicate key field marks a nd shortening the text to the minimum n eeded to identify a bird, Peterson produced a reference book that r evol u tion i zed b i rd watching. H i s first fie l d guide, A Field Guide to the Birds: Giving Field Marks of all Species F ound in Eastern North America, was pub l ished in 1934 (Fig. H -37). In 1980 range maps reflecting the seasonal move ments of each species were added t o the guide. A Field G uid e to the Birds was the first of a series of field gu i des that would make publishing his t ory. More than anyone else in the world, Peter son introdu ced iln e n ormous number of peop l e to birds-an ach i evement that far surpasses the commercial success of his series. As spec ies rec og niti on i s the first step toward preservation, his work a lso has been pivotal to the 20111 ce ntur y conservat i on movement. Academic Training in Ornithology I\ H l,;\l. 11\.Q.,, o"i'>lt Orni thology became increasingly profes siona l in the ear l y part of the 20111 century. Al though no formal degree programs were yet available, a number of academ i c institutions offered classes in o r nitho l ogy as part of zool ogy or n ature study programs. A period of rapid expans i o n soon followed, with more students interes t ed in ornithology, and more in-depth, sci entifical ly-based stud ies of birds being carri ed out. As the f i e l d grew, graduate degrees became standard requirements for serious researchers. Biol ogy itse l f was rapidly transformin g from a Tf:Rt'IS ""'" descriptive discipline to a n experimental one, with a number of spe cialized f i e l ds s uch as genetics, embryo l ogy, and the (ield-based stud ies of ecology and animal behavior. During the early 201 h century, Cornel l University was the l eading institution for gra du ate training in ornithology. From its beginning, Cornell had a stro n g prog r am in zool ogy but once Dr. Arthur Allen a rriv ed it earned a r eputation as an important center for bird studies, Allen wasn't the first person to earn a Ph.D. by s tudying birds, but his research was the first to be widely publicized. His Ph.D. dissertation, The Red-winged Blackbird: A Study in the Ecology of the Cattail Marsh, published in 1914, set a new s t a nd ard for documenting the ecology and life history of a b ird spec ies. A year after h e graduated A ll en was offe r ed a position as an Instructor of zoology at Corne ll. In 1 915 he was promoted to assistant professor of orni thology and developed t h e first g raduat e program in ornithology in America. Many of A ll en's students including Ludlow Gr i scom, J ohn Emlen1 Peter Paul Kell ogg O l in 5. P et t i ngill, Jr., and George M. Sutton, went on to become l eaders in eme r ging biological d i sciplines. In addition H andbook o('Bird Figure H37. Plate from an Earl y Peterson Field Cuide: Roger Tory Peterson rev olutionized bird watching in 7934 when he p11hlished A Field Guide to the Birds: Giving Field Marks of a ll Species r-ound in Eastern North America. This pl.1te of terns and skimmei'S from a 1939 edition o( the hook shows the unique system of arrows Peterson used to indicate impor /ant 17eld m

H38 F ig ur e H -38. P e t e r Paul K ellogg_ Ar thur ,4. Alle n and /am es Tann er: Seen here 1 vilh photographic and soun d recordirJ g equipment Peter Paul Kellogg ( / eft) and ArthurAIIen ( center ) were leaders in de veloping the technolog y to record bird sounds. The success of this technology, a/ongwiththebelielthattlrepubliccould contribute to the professional study of birds, led Allen t o iound the Cornell Lab of Ornitholog y and its Library of Natura l Sounds Photo courtesyofCome/1 Lab of Ornitholog y Archives. to his impressiv e l ist o f academic progeny Allen was o n e of the first professors to teach courses in wildlife con servation and management. H e a l so was a leader in popularizing b i rds-offerin g m any courses to the pub l i c on bird ident i fication and p h otog r ap hy, and writing ma n y articles for BirdL ore a n d National Geographic. Through the work o f Arthu r Allen and Peter Paul K ellogg along w ith t h e f i nancial support o f Albert Brand Corne ll beca m e a l eader in developing the t ech n ology to record bird so und s (Fig. H-38 ). This tr adition con t i nues to g row today w ith the Library of Natu r al Sounds and Bioacoustics Pro g r a m at the Corne l l L ab of O r nith o l ogy. C l ose o n Allen's heels, academically, was joseph P. Grinnell of the Museum of V erteb r a t e Zoology at the Univer sity of California at Berkeley Ann i e Alexander, a wealt h y n atura l ist and collector founded the mus eum in 1909 and appointed Grinne ll its first director. Grinne ll earne d h i s Ph.D. in 1 9 1 3 at Stan ford Uni vers ity by s tudyin g the m a m m a l s and bird s of the Lower Co l o r ado V a ll ey; a study now con sidere d a class1c i n biogeogra phy. After he earned his degree, Grinnell's appoi nt ment was ex p an d ed to inclu de a professorship i n the D epar tm e n t of Zoology at U .C. Berkeley. Grinnell raised orni th ology to new sc i e nti f i c l evels by setti n g new s t andards fo r colleclfn g exped i t i ons empha s izing ca refu l n ote-tak in g and record keepi n g, and accu r ate labeling of speci m e n s He also p l aced con siderab l e emph asis on accumulati n g an d carefully document i n g data on eac h species Like A ll en at Corne ll Grinne ll produced an impressive academic line incl uding s tud en t s such as Alden Miller, Frank Pi te l ka, Ned J ohnson Char les S i bley, an d Robert Storer A l though Cornell U n ivers i ty and th e Univer sity of Cal iforn i a at Berkeley were t h e most prolific academ i c in s titu t ion s i n the 1920s and '30s, seve r al other un i vers ities a l so est abl i shed active o rnitho l Cornell Laborator11 of Omitholo8'1


Birds ana H u m a ns: A Hist o rical P e r spedive ogy p r ogra m s Amon g t hese wer e Case West ern R ese r ve i n Ohio, the University of K ansas, a n d t h e U n ive r s i ty of M i chiga n T oday ove r th i rty uni ve r sit ies i n Nort h Amer i ca offer gra du ate degrees w ith t h e opp o r tu nity to p ur sue a d vance d stud ies of b i rd s As aca d emic r esearc h has expa n ded, so has t h e bod y of knowl edge con cern in g birds. B eyo n d c lassi f i ca ti o n a n d l i f e h isto r y studies, bi rds h ave served as model s fo r s tudies i n a diversity of biol og i ca l fie l ds, i n c ludin g biogeography, evo l ution m a t i n g sys t ems, popu la tion dy nam ics, eco l ogy, animal com mu n i cat i o n a n d l earni n g ne u ro bi o l ogy, a n d co nservation I n th i s way, birds h ave h elped u s deve l o p a better u nde r stand i ng o f t h e n atural worl d. B ird C on s ervat i o n B i r d Wat ching, a n d the A g e ofTe chno l o gy Birds a n d bir d watche r s have bee n c r i ti ca l to t h e fi eld of wil d life con servatio n. Because birds a r e r e l a t ive l y access ible to obseNers, t h ey are important warn in g flags f o r th e w i d e-sca l e e n v i ro nm e ntal c h anges cause d by people. Growin g publ i c concern about t h e fate of birds has bee n key to passi ng fede r a l l eg i s l a t ion prot ec ti ng birds and oth e r wil d l ife. T h e Lacey Act of 1900 was the firs t federa l l eg i sla tion offe ring so m e prot ection for b irds, a n d i t ca m e abo u t largely throug h the efforts oft'he AOU b ird p r o t ect i on com m ittee, the U.S. Biolog i cal Sur vey, a n d A udubon supporters These groups a l so hel ped to create the firs t n ationa l wildlife refuge-P e l i ca n I s l and in F l o r ida h o m e to a col o n y of nesti n g B rown P elicans The A udubon Society also p l ayed a key role in passi n g the Fed era l M i g r a tory Bir d T reaty Act of 1 9 1 8 a law that fo r t h e fi rst time pro t ected a l l m i g r a tory bTrds i n Ameri ca. T h e E n dangered Species Act of1973, r e autho r ized in 1988, gave even mor e weig h t to securi n g t h e f u ture of e ndan ge r e d a n d t h rea t e n ed bi r ds. T h e Wil d Bird Con servatio n Law, passed i n 1 992, ba nn e d t h e impo rt of all birds listed by CITES ( t h e Conve n t i on on l n l e rnati o n aiTrade in End a n gered Species of W i l d Faun a a n d Flora). For more i n formatio n on l eg i slatio n af fect i ng birds, see C h a p ter 10. T wentieth centu r y na ture wri t ers and a rt ists have don e thei r par t to i nsti l l an env i ro n menta l ethic i n the American publfc. Amon g the classics are Alclo leopol d's A San d County Almana c !1949), which focuse d o n the ethica l use of l a n d ( F i g. H 39 ) and Rache l Carso n s Si l e nt Spring (1962), w hich i n d i cted t h e use of pes ticides. There a r e ma n y more-each book nu dg in g t h e reade r for wa r d to g r eate r awa reness and apprec i a tion of Jhe natural worl d. Among the 20'" ce n tury a r tis ts, L ouis Agassiz F u e r tes stands o u t for his ability to captu re, with pen a n d brush t h e essence o f Handbook of' Bird Biolo[Jtf H-39 Figure H -39. A/ d o Leopol d : Considered the lather of modem lvilcllife tnll1d8f.' ment Aldo Leopold is shnwn here preparing to weigh an American Woodcock ,Js part of his t 1eld researc h Leopold' s 1949 book A Sand Co unt y A l mana c, iocusc'<:l on environmental stewardship and the ethic,JI use or land. Photo b y Robert Ockting courtesy or The A/do L eopold Foundalfon Archives.


H-40 Figur e H-40. American Kestrel by Loui s Agassi;z Fuertes: Fue rte s abili()l t o c ap lure the esse n ce of a bird's clwr,1c t c r is exemplill e d b ) this Ameri c,l/1 Kestrel fee din g on a g rasshopper. Thi s paintin g hang s in the h a lls of the C ornell Lab o f Ornitholog y in Ithac a N e w York, and is one of the mos t p o pular among the gen era I public. Cow1eS ) of C om e// Lab o f Ornithology. Sand'/ Podulka. Marie Ecklwrdt. a nd D anie l Otis the living bird (Fig H-40). A l though he died in 1927, his work is still unsurpassed and hi s influence is apparent i n the paintings of many art ists working t oday Other great bird artists of the 20' ce ntu ry in clude George M iksch Sutton Roger Tory Peterson, Larry McQueen Robert Bateman and Don E c k l eberry. Today, bird wat c h in g has b ecome bi g business. Bird feeders, bird foods, bird baths binocui

gives birders a n d researchers all over the world a cha n ce to v iew and i n terp r et the resu lts insta n taneo usly. Other web sites, such as one operated by t h e United States Geolog i cal Survey's Patuxent Wildlife Research Center, also functi on as a clearinghouse for i nformat i on on b i r d popu lat i ons At th i s one s i te birde r s and resear chers can access data a n d other i nformat i on f rom a var iety of sources, i n cluding t h e North Ameri can Breeding Bird S u rvey, hawk migration counts, night b ird monitori ng, marsh bird monitor i n g, and the Co l o n ia l Waterb i rds Invento r y a n d Monitoring Prog r am. Because t h e I nternet can handle bird distr i bution and abundance data from hu ge numbers of observers so rapidly-anal yzing and d is p l aying i n m i nutes data sets that previous l y migh t have taken years to input and process-it is a powerful conservation tool ( fig. H-41 ) Having instant access to large amounts of data permits scientists to evaluate changes in bird popu lations over time allowing conserva tion biologists to take action whilespeci esa restill r elative l y common. When bir d watchers tak e part in these o n-line counts a n d other bird wa t ching p r ograms, their observations are mak i ng valuable cont ribu t ions to b ird conservation. S uaaested T\eadinas Barrow Mark V. )r. 1998. A Passio n for Birds, American Ornithology after 1\udubon. P r inceton, New Jersey; Princeton Univer sity Press. Handbook of Bird Bioloeq H41 I Figu re H-41. Abunda n ce and Distribu tio n o f Downy Woo dp ecke r s ,15 R ec ord e d b y Creal Bac kyar d B ird C ount Par ticip a nts in F ebruary 2 00 0: The power of the lntemet is shown in this example from the Cre

H.42 Sandlf Podulka, Marie Eckhardt, and Daniel Otis Buxton, E ) M I 985. "Bird s i n Poetry." pp. 475-478 i n A DidionaryofBirds, e d by B. Campbell and E. Lack. South D a k o ta: Buteo Books. 670 pp. Feld, Steven 1990 Sound and SenUme n t ; Birds Weeping, P oetics, and Song in Kalttfi E xpre.5sion, Second Edition. Philade lphi a PA: Unive rsity o f P e nnsylvania Press. Haii-Craggs, ). M. and R. E. )ellis. 1 985. "Birds in Music." pp. in A DfctionaryofBirds, e d. b y B Cam pb ell and E. Lack. South Dakol3: Buteo Books. 670 pp. Lambourne1 L J985 "Birds in Art." pp. 23-25 in A Diction ,lr) of8/rds, ed. b y B. Cam pbe l l and E. lack South Dakota: Buteo Books. 670 pp. Laubi11, Reginald and G l a dys. 1976. Indian Dances of North A merica; n1eir Imp orta n ce to India n Li(e. OK: U niversity o f Okla h oma Press. Roseman, M a rina. 1991. Healin g Sounds from the Ma l aysian R ainfo rest Temiar Music and Medicine. Ber kele y and Los Angeles: Universit y o f Cal ifornia Press. Stresema n Erwin. 1 975. Ornithology. From Aristotle to th e Present. Cam bridge ,\ItA: HarvMd Universit y Press. Turner, G. E. S. 1 985. "Birds in Fol k l ore pp. 233-234 i n A Oicti o naryof8irds, ed. b y B. Cumpbell and E. lack. South Dakota: Buleo !.looks. 670 pp Cornell LaboratM1 of


Introduction: The World of Birds Kevin}. M c Gowan LIJ Every chi ld knows what a bird is. Birds exist o n eve r y contine nt, i n every climate and over every body of water. Everyone has seen them and recognized them. But w h at exact l y m a kes a bird a bird ? Lik e f ish, amphibians reptiles, and mammals, birds a r e ve r te bra tes. That is, they a r e supported

1-2 Figure 1 1 B .un Swallow: Feathers are unique to birds. Here, a Barn Swallow stretches its right wing, providing an ex cellent view of the individual fe,1thers. Photo by Marie Read. Fig ur e 1 2 Northern Harrier in Flight: Although not alone in their ability to t1y, birds are thoroughly modified for proficien cy in the air. Northern Harriers-slender, longtailed hawks with long wings and a conspicuous white rump pa/ch-typically fly low over open fields a nd marshes, gliding and tilting lrom side to side with the wings held in a sh;il/ow V, as they search for meadow voles and other pre)!. Drawing by Orville 0. Rice. K evinJ. McGowan Unique to birds are feathers o u tgrowths of the ski n t hat cover and str eaml i ne the body (fig. 1 1 ). Another special feature of bi rds, perhaps t he most obv i o us, is t heir ability to fly (Fig. 1 2) A l tho u gh f l ight i s not excl u sive to birds-bats, for examp le, have also evolved true f l app i ng flig h t no othe r verteb r ate is so t h oroug hly modified for proficie n cy in the air. Most b i rds can i ly, and t h ose that cannot, such as penguins evolved from a n cestors tha t were capable of flight. Corne ll Laboratwq of Omitlwloaq


Chapter 1-1 ntroduetion: The World of Birds Ornitholo9ical T erms Ornithology, the scientific study of birds, embraces a vast store of knowl edge acqui r ed by many thousands of researchers. Over the years these scientists have developed a terminology for cer t ain struc tu res, processes and concepts that may strike nonscientists as being unnecessarily technical. For some terms this may be true but many other technical terms are used because no adequate or concise substi tutes exist in everyday language. Technical terms also help scientists to convey very specific information with a minimum of confusion, in the same way that legal wording allows members of the legal profession to avoid ambiguity in contracts. This Handbook of Bird Biology minimizes the use of technical terms, using them only when necessary to clearly explain the material. To get you started a few basic directional terms are described in Sidebar 1: Which Way i s Up? The Form of a Bird Undoubtedly, you know what "a bird" l ooks like. But how closely and carefully have you really looked at a bird? Have you ever noticed the scales on the legs? Have you seen the small, whisker-like feathers around the bills of insect eating birds? Do you know where a bird's knee is, or its ankle? One goal of the first section of this chapter is to help you understand the basicformofa bird. This knowledge provides a framework within which you will be able to identify, describe, com pare, and eventually classlfy the different kinds of birds. A live bird in the hand is an ideal aid for study i ng bird form Any pet bird such as a parakeet, finch, domestic fowl, or Rock Dove (pigeon) wi II do, but a fresh road or window casualty also can be used. In the United States and Canada, however the only casua l ties that can be l egally remoVed from the road or window sill for persona l study are non-native species: Rock Dove, House Sparrow, and European Starling. All other North Amerlcan birds a r e protected by the Migratory Bird Treaty Act (see Chapter 1 0>; it is Wegal to possess a carcass a living specimen, a nest or egg, or even a feather of protected species without the appropr i ate permits. To study some avian features, even a whole ch ick en or turkey from the grocery store can be helpful. I f you can get one with the head and feet still on it, great but you can learn a few things even from one that is ready to cook. If you prefer to learn from live wild birds you mightgo to the park and study t h e pigeons, House Sparrows or ducks that come to the bread you throw out, or watch the birds at a feeder next to your window. In any way you can get up close to birds and observe the details. For descriptive purposes the bird's body is arbitrarily divided Into seven major regions; each of these, and t heir major parts, are considered in turn On your subjec t bird, first note the shape of the body-how ittapers at both ends, perfectly stream I ined forflight. Then identify the seven main parts ; beak head, neck, trunk, w ings, tail, and hind limbs (fig. 1-3). (COntinued on p. 1 6 ) Handbook of Bird BiolOfjlj 1


1 Sidebar 1 : WHICH WAY / 5 UP? Kevin J McGowan Leftorright?Whose left yourso rmine ? Behin d or in front? Of you or me? Direc tions can be t:onfusing when they use a rbitrary reference potnts. When face to face, my le ft i s your right, and vice versa. When discussing anatomy, keeping directions straight is imperative UnfQitunately, many directional terms used in everyday speech are not specific e nough when dea I i ng with parts of the body. Such words as low er" or '' upper '' and "backH o r ' front'' can be confusing when trying to discuss parts of an animal. For C.Mample, stand ur straight with your hands hanging at your sides. A r e your fingers above or bel ow )'Our el bows? Ho l d your hands over your head. Now where are your fingers in relat io n to your elbows? Wh tn the bird). On a tree, the e nd s of the branches are distal to the inner branches. left: Always refer s to the animal's left side nor that of the observer. Kevin J McGowan Rig ht : Always refer s to the animal's right side, not' that of the observer. Caudal: T oward the tail C ranial: Toward the head. The body is always caudal to the head; the neck is always crania l to the tail. Whe:n you reach the head or neck and stil l want to describe forward positions what do you Use the following: Rostral : Toward 'the beak. For rositions on the head and neck. The nasal openi n g is rostml to the openinff. Although rostral is the official term tor directions toward the beak on tf1e h ead and neck in much or the literatur e a nd in everyd.1y language, crania l and ant e riur are often used. This course uses the terms in terchangeably, when their meaning Is c/e;)r Anterior: T oward the f r ont. Pos terior : Toward the back. Anterior ,1nd pos t erior can be confusing, thev use an oulSide frame of reference--the earth, Fora s tandin g penguin or person, the belly is .mterior and the back is posterior. O n ,, swimming penguin however, the head is anterior <1nd the tail, posterior. Officially, r.he terms anterior and posterior shoul d be used only within the eye and inner ear of a bird. In much of the lit erature and in everyday language, ho wever; anterior andposterior are used interchangeably with c:ranial and caudal. In places whe r e anterior and posterior are not confusing, this uses them interchangeably with cran ial and cauc/,11. Transverse Plane: A vertical plane throug h a bird, di v iding the body into cranial and CCI udal portions Frontal Plane: A (usual ly ) horizontal plane through a b ir d, dividing the body into dorsal and ventral port ions. Sagittal Plane: A I plane through the l ong axis of a bird, extend ing from head to tail. It divides the body i nto lef t and right portions. These terms ref er to planes of sectio ning through an animal and are used in the Handbook ofBird Bio l ogy to describe the perspective from whic h variou$ sec tional views oi a bird's in ternal anatomy are shown. Now, if you stand straight up with your h

Chapter Introd uction: The World of Birds 1 Right R()s/la/ L eft Figure A. Anatomical Oirectiomr : Researchers crsespecilic terms to refer unami Jiguouslyto directiOns and relative locations on the bodies of animals as illustrated here. Toward tl1e back is termed dorsal and toward the belly is ventral; toward the midline of the body Is medial toward the side Is and something positioned on the mirlllne of the l?ody iJ; median ; toward the center t1f rl1e body i s pro vim a l and away from the center Is distal To describe toward the head nr tail cranial and caud,1l are ge n emlly used, but anterior and posterior may be used as well. altl1ough their use is sometimes limited to sites wit h in the inner ear and eye. To refer to something in the direction nf the tip oft he beak from a. point of reference on rhe h ead lsee inset), the term rostral is used. The tenn s left and right refer to the animal's own left ,Jnd r ight not those of the observer. II is also vseful tor certain anatomical seclianil l ylews, to refer to planes cut throvgh an animal. For a bird in the position illvstrated a plane e,vtends vertically from head to tall a transverse plane extends verrically from side to side, and a frontal plane tends horizontally. R eprinted and adapted from Manual of Ornithology, by Noble 5. Proctor' anrl l "atrick f. Lynch, with sion ol the p(lb(lsher. Copyright 1993, \1!/e Univers it y Press. H andboo k of Bird Bioloatt


I 1 figure 1 -3. Bird Topography: Birds /rave s even mnin topographic regions: beak head neck lwnk wings, tail, and hind liml)s To facilitate idenrifi c a,; o n and description, ornithologists divide many of these regions furthet Drawing by Charles L. Ripper. KevinJ. MeGowan Bill The b i ll has two parts, the uppe r beak <1r1d the l owe r beak ; the upper beak slightly overlaps t h e lower beak when the b ill is closed. As you study birds, you undoubted l y wi l l come across other terms for the upper and lower beak, such as the 'maxilla" ( upper J and "man d i b le" (lower ) or the "upper and lower mandible." Because "max i I I a" technically refers to a specific bone, and m andib le" can have various meanings, this course follows the use by Lucas and Stettenheim(1972 ) of "upper and l owe r beak" to refer to the b ird' s jaws. The bones that make up the beak are the premax illa ( upper beak) and dentary ( lower beak) (see Figs. 3-33 and 4-8) A l though today the terms ''bill' and "beak are used i nter c hangeably, the term beak" W

Gtapter 1lntrodtJCtiollc The World of Bird5 Nictitating Membran& Head and Neck tyelid Lower Eyt1lttl As yo u read this section, refertotheprofileofthehead and neck in Fig. 1-4, as well as Fig. 2-8. Caudal to the upper beak are the forehe a d c rown and nape. The nape is actually part of the neck. Running back from the upper beak and bel ow (ventral to) the boundary of the fore head and crown is the eyebrow s tripe o r s upercilia ry line (also called sini p l y the eyebrow"), which is distinctively colore d in some birds. The eye is very large. On l y the dark pupil and s urrounding col ored iris show; muc h more of the eyeball lies under the skin. In most birds the combined s i ze of the eyes is larger than the brain! In some species, the eye changes c o l or as the bird ages. American Crows have grayish blue eyes while in the nest, but their eyes quickly turn the same dark brown as adults' eyes within a month or so. ( 0dd1y Australian crows and ravens start out with clark eyes that turn to pale white as adults.) Birds have three eyelids: the upper eyelid the lo we r eyelid1 and a "th ird eyelid,'' the nictitatin g membrane-a thin t.ransl ucent fold that sweeps across the eye sideways from front to back. The nictitating membrane moistens and cleans the eye and protects its surface. A ll birds blink from time to t irne, but most b link regularly only with the nict it ating membrane. In raptors and other predatory birds, the nictitating membrane protects the eyes as the bird pursues prey through heavy cover, such as a blackberry thicket. Birds close their eyes-usually by raising the lower lid -when they sleep or when their eyes are threatened by something If you have a live bird gentl y move your finger toward the eye and wat c h the response. Does the Handbook of Bird Bioloe'f 1 Figure 1-4. Regions of the H ead and Neck: The head and neck regions are sunrlivTrled Into il number oi smaller areas, These subdivisions allow re searchers a nd birders to give precise of ,1 bird. Note r()ar rhe s uperciliary line i s also c,11/ed the eye brow stri pe o r simply the "eyebro>v"; i!llld a s tripe in the mal11r region may be called a malar s t ripe a mustache or a whisker stripe The dose-up view of the eye shows the tipper and lower eye/iris fully open. A third eyelid, termed the nic titating membran e is patlially coveting the e)'l?; as it swef!ps to close from/eft to rig ht This trilnslucent inner eyel id pro tects .the eye while s till permitting bird s t o Set". Drawine b)' Charl'5 L. Rippero ---


1 External Ear Opening Fi g u re 1-5. Auricular Feathers o f a R uffe d Crouse: Tile auricular (e

Chapter 1-l nt r oduction; The W orld o f Birds 1 / ummingbird Trunk The rather comp a ct trunk o( bir d s i s divided int o t h e back, ru mp breast, belly, sides, and flanks (see Fig. 1-3 ). Otten t h e sid e s and f lanks are parll y co nceale d by t h e w ings a n d v i s ibl e only w h e n t h e bir d is i n flight. Win9s The w in g of a bird (fig. 1-7) is structure d l ike the f o r e limb of a n y a mphi b ian, reptile, o r mammal w ith t h e sam e Lhree d i v i s ions: t h e uppe r arm o r brachium ( pr o n ounced BRA KE-e-urn); the f o rearm or antebrachium; a n d t h e h and, o r manus. To unde r s t a n d t h e wing, com par e i t t o t h e human forel i m b as you go a l o n g (Fig. 1 8 ) If you have a chicken wi ng, b o il i t until t h e meat co mes off and lo o k at the bo nes. 1-9 Figure 1 6. Bird Neck : AI/ birds have long necks. meir necks do not Jppear long beca use they arc folded in an 5 shape and concea led beneath fe.1thers. Even birds such as q uail, chickadees and t he lrumminglJird picJured h ere which appear ro have lilli e or no neck, actuall y have relatively long necks. me large dark ,1rea in this diagram is he skull anrl the long thi n dark struCture c u rving dnwn from it indica tes the chain of vertebrae tllal make u p the neck. Arlaptecl from Gill ( 1995 p 94 ) C.up efs Radiale P lralanges of Digit2 c>! Carpometacarpus Phalam( oi Digi/J Figure 1-7. Bones of the Wing : Til e wing of t. In birds the c arpals (wrist bo nes) are reduced to t wo bones tile radiale and ulnare and the metacarpals (palm bones)

1-10 Human Arm Figure 1-8. Bird Wing Compared to Human Arm : Although the wing and arm have the same three main sections, the manus and antebrachium mak e up a /argf!rportion of the bird wing, proVidinq a long attachment site, for the primary and secondary flight feathers. These two sections are what you see the wing when you watch a bird in flight, as the brachium is short and close to the body-the division between it and the antebrachium i s generally obscured by feathers. The large muscles that move the wings attach to the humerus, moving the entire wing by moving the humerus. The alular quills-a small group of feath ers attached to the first digit-form the a/ula, which helps to keep air flowing smoothl y over the upper surface of the wing. Drawing b y Charles L. Ripper. KevinJ. McGowan Manus In both the wing and human arm, note that the brachium is sup ported by one long bone the humerus ; the antebrac hium by two long bones of unequa l size the radius and the l arger and thicker ulna ; and the manus, by a series of bones that vary in number size, and thick ness. These are wrist bones or carpals ; palm bones, or m e tacarpals; and finger bones or phalanges (singular phalanx). Observe that the wing has fewer bones than the human arm because many are fused or absent, l eaving two carpals, the radiale and ulnare ; one big, fused pa l m bone the carpometacarpus ; and four phalanges all the bones that remain of the first three fingers. Only the middle finger, with two of the four phalanges is still large. The skeleton of the wing is significantly lighter than that of the forelimb of any terrestrial vertebrate. The long bones are actually hollow; the humerus is even invaded by an air sac from the respiratory system (see Fig. 4-82). Furthermore compa r ed to your arm, most wings are additionally lightened by having no l arge muscles. Their principal movements are controlled by tendons coming from huge muscles on the breast This arrangement takes weight away from the wing and brings it nearer to t he bird's center of gravity-a more stable arrangement for a creature that must fly. Cornell


Chapter /-Introduction : The World of Birds Spread out the wing of y o ur specim e n and b y feelin g und erneath, identify the bi g bones under the s kin. Observe the fo ld of skin the pata g ium that extends from the brac hium t o thea nt e brachium essen tiaJi y connecti n g the s houlder to the wrist (Fig. 1-9). The patagium i s c overed with f e athers a nd forms the lead ing edge of the inner wing in fli ght. A smaller humeral patagium exte nd s from t h e brachium to t ht> trunk. The p r om in e nt angl e at the wr ist i s common l y called t h e bend of the wing G e ntl y open a nd dose the wi ng, obse rving the acti o n at each mai n joint. The w in g of a bird i s not as mobil e as yo ur arm. Not e that the wing cannot rotate in a full circle a t the shoulder as yo ur arm can no r can the manus rotate at the wrist as yours can. The joints of t he wing a r e formed on l y for specific m oveme nt s in flight, \.Yhereas those i n your arm are design e d for a mul tit ud e of differ e nt funct ions. Chapter 5 describ e s pr ecise l y how a bird uses its wings in flight. Refer to Fig. 1 -10 as yo u work through the fo ll owi n g in for m ation o n the feather g r o up s of the wing. The longest wing feathers are the flfght feathers, or remi g e s ( singu l a r remex), the l o n g, stiff qu i lls that ex tend distall y frorn the bones. The r e miges a r e stiff feather s tha t form the predominant air-cat ching portion ofthewing.Abov e these feathers are the coverts the s m aller feathers t hat overlap the f li g ht feathers at their bases lik e evenl y spaced shingles o n a roof. From two to six ( u suall y three ) alular quills ( pronou nced Al-yo u-lar; a qu i II i s a fea t her) project from the phalan x of t h e fir s t finger (the bird s thumb ''; see F i g 1-8) at the bend of the wing. The a l u l a r qu i ll s make up the a lul a s ometimes k n own as t he "bas t ard wing ," wh i c h can be spread apart from the rest of the wi n g and is used fo r fin e control of airfl ow ove r the w ing. The remiges emergin g from t h e manu s are the prim aries and those f r o m the antebrachium are the secondaries. By feelin g t h e ir bases under the w ing, you will f in d ( in flyin g birds ) that a ll are firml y attac hed t o t h e skeleton b y ligaments the prima ries to the bo nes of the manu s a nd the t o the u lna. A toug h b a nd of tend i nous tissue, the postpatagium a lso holclstheremige s firmly in plac e a nd supports each qu ill (see F i g 1-9). Each indiv idual within a species no rmally has the same number" of r e miges Overly ing each r e m ex o n the upper s ur f ace H a ndb ook of Bird Bio lo8'1 1 .11 Figure 1-9. Patagia of the Wing: 1\ fold oi tough skin the palagium extends from the brachiu m m thr> a nt ebrachiu m connecting the shoulde r to the wrist. Cove red with feathers, it forms the I lead ing edge uf t h e inner winJ:: durin g flig ht. A smalle r fold of skin the lwmera/ pata g ium ex/ends trom rhebmchium ro rhe tr unk. During fligh t th e l o n g wing faathers mu .st be ,11Jie to withst.wd th e force of the ,J/r moving b y them A l1.1nrl oi tough tendinou s tissue the pos lpa tagium s urround s th e bases of the flight le< llllers, supporting and h olding them In p l ace Adapter/ fro m f'rot;Jor and I/99J, p I U ll.


1 I of the wing is one g r eate r primary covert or greater secondary covert. Overlying the g r eater coverts are the m edia n coverts and overlying them are the lesser coverts A ll are in distinc t rows. The remaining feat h ers that compl ete the forward roofing of the win g are t h e marginal coverts. Flna l ly, n ote agai n the a lul ar quills ove rl ying the bases of the grea t e r prima r y cove rts. Other f eatures o i the feathering that you s h ould note are the s capulars a g r oup of feathe r s e m erg in g from the upper surface of the bra ch i um and shoulder bu t not a tt ac h ed to the bone; the underwing coverts ofte n col l ective l y called the l ining of the win g''i and the axil laries a cluster of feathers i n the '1armpit" that are recognizab l y longer t h a n those lining the win g. Tail Th e tail of a bird 1s technical l y a s m a ll bony a n d fleshy structure marking the e n d of the vertebral colum n but most people including ornith ologists use the t e rm "taiJ'I to mean the feathers a r isi n g from the "official" tail. The long, stiff flight feathers of the tail are the recfrices (sin gula r rectrix); the s h orter feathers overlying their bases, above and below, are the coverts ( ca ll e d the uppertail coverts a n d undertail cover t s respectively ) The rectrices are pai red o n e m embe r of each pair on eac h sideofthetail, with n o feather in the middle(see Fig. 3-7). Most birds have five o r six pairs, but some I ike the Ruf f e d G r ouse, h ave m ore. Like the flig ht feathers of the wing, the numbe r is the sam e in each species (w ith o nl y the occas i o n al mutant). Not e that when th e tail is not s pr ead each rectrTx is over l ap p ed by I h e o n e next to it; the exceptio n i s one of the m idd l e pair, w hi c h lies on top. B eca u se the middle lor ' deck") feathers protect the oth e r feathers, they often a r e the most : bad l y worn of the rectrices Hind Lmb s As in the w i ng the structure of the blrd s hind limb i s simil a r to that of a human with three divisions; th e upper leg, or thig h ; th e lower leg, o r crus ; and the foot. Unlike the h indlimb of a human, h oweve r the foot has been elongated and modified into two functiona I sect i o ns, mor e like the hind limb of a h o rse or dog. In most birds the th i g h b one i s rath er s hort and often hidden by b ody feathers. Because of the e l o n gated lower leg and foot, a bird ha s three e l e m e nts to the l eg, n o t just two as in the h uman l eg Note that b ird s' knees bend in the same direct i o n t hat yours do, but the ac tua l locatio n of the knee can be con fusing. J ust as the l e ngth of t h e n eck is hidde n by p os tur e a n d feathe r s so, too, is the thi gh hidden f rom sight, making t h e a nkl e appear to be the knee. TI1ehind limb of a bird and human a r e compa r ed in Figure 1-11. First, notice that in bot h, the thfgh fs supported by o n e l ong bone, the femur. Nex t note t hat in huma n s the cru s (lower leg) is s upport ed by two long bo nes, t h e tibia and fibula and the foo t i s co mpos ed of a se ries of bones: t h e a nkl e bones ( tarsals) the r n step bon es( m etatarsals ), Come II Laborator'1 of Ornttho lo9tt


C h .apt e r 1-/ ntroduetlon : The W o r ld of Birds Blue Jay Ma!lllnal Covert> ---t'-Mert> GiP.ater So.ondeondaries Fig ure 1-10. Feathers of the Wing s and T ail: Themajorgroupso ffeat ht'r s are i/lustmted in dnrsrll view on,) Blue a nd in , e ntral view on a Great Egret. Note that the details of feather a r rangement-such as numbor. size and s/J.1pe-vary dramatic.1/ly among different species, but that the same main gro u ps of feathers are present in most birds. The inset, a view of,, Roc k Dove wing, shows a detailed vie"' of the secondary co terts. See text for a description of each fcacher group. 13/ue lay ant;/ Great Eeret reprinted from Manual of Orni t h o logy, by NobleS. Proc tor and Patrick} Lynch, wit hpermis sionoft h epubllsher. Copyrigh t1993, \ '.1/e University Press. Inset adapted from Proctor and Lynch { 1993 p. 59). H andbook of Bird Biolo[jlf


1-14 Tiblotarsus -----,......,...,/ (Fused Tibia, Fibula, and Some Tarsal Bones) --Tarsometatarsus 1\evlnJ. McGowan Crus (Fused and Meta tarsals) F igure 1 11. Compa.riso n of Human Leg and Bird Leg: The leg of both b irds and h umans has t hree m(lin divisions; the thi g h ( upper leg), the crus ( /owerleg), and the foot. In both birds and h u mans t h e t high is supported by il single bone the f e mur. Two bones, t he tibia and fibula, svppo r tthe crus in humans In birds, however, the crus is s u pported by a s ingle l ong bon e. the tibiotarsus-lhe familiar Kdrumstick" o( a cooked turkey. .The r ibiolatsus is formed by the fusion of the tibia with two ot more of rhe tarsal/ ankle ) bones. The fibula Ts present but reduced to a fine, need l elike bone running about tvtothirds of the way down thesideoflhetibiotarsus.ln.addition to the tarsal /ankle / bones the human foot consists of metatarsals (insrep bones ) and phalange s (toe bones). The b ird foot however. is q1.1it e dit: ferent. It has been elongated a n d modi/led into two functional 3 Tarsals ( Ankle Bones) Fnol sections. The upper section consists of a ;in g le fong IJone, the tars ometatarsu s (also called simply the m e labrsus), formed by the fusion of the remali1ing tarsals and m ecacarsals. T/11} lower section consists of the phalanges. Birds have four toes, at most although their arrangement differs from species lo species. On e common arrangement shown here for a birds right foot, is with t he tlr>t toe termed the h allux pointin g back a n d three toes in numbered from medial to lateral. AI first glance, the sections of u blrcl's leg can be c onfusing. Tl1e thigh is short and along with the knee usually hidden II}' t he budy feathers. Thus, the joint that appears to be a knee bending b,1ckward is actually the ankle. A bird's knee bends in the .

Qtapter 1-1 ntroduction : The World of' Birds and the to e bones (phalanges ) Compare these bones with those in the bird and yo u will see numerous differ e nces. In the crus of a bir-d there is only one long bone the tibiot a r s u s exte ndin g between the knee a nd heel ( thi s is the c hi c k e n' s "drum stick ") The tib iotarsus is a fusion o f the tibia w ith two or mor e of the tarsal bones. What there is of the fibu l a is a needl e lik e b o n e ( perhaps yow have noticed it w hen gnaw in g on a drum stick) runnin g twothird s oi the way dow n the side of the tibiotarsus. In some birds, such as the turkey, the t e n dons t hat connect the le g muscles with the toes are calc ified (stiffened by deposited calcium salts, like those in bone ) and may appear to be small thin bones. The foot of a bird contains one l ong bone the tars ometa tarsus, a nd the phal anges of the toes. TI1e tarsometatarsus-sometimes called s imp l y the m etatarsus--represen t s a fusion of tarsal s (ankle bones) and m e(atarsa l s (tn s tep bones) and f orms the skeleton of the tars us, the gen eral name for the sectio n of the fool between the hee l and toes. Birds have, at moslj four toes, and each one bears a claw. The toes are given numbers to cor r espond w ith those of birds' a ncestors. The earliest vertebrates had five toes, a ll of them po inted forwa r d (Fig. 1 12), numbered ( by researc hers) f rom the i nside out ( medial t o latera l ) In birds, the first toe (if present ) proje cts backward and is called the hallux Thus, the second to e of ear l y v ertebrates is the innermost toe of b irds. Man y species of bird s have no h a ll ux with o nl y t hree forward-facing toes. Ostriches have onl y two toes (Fig. 1 1 3) Because the tarsus i s elevated, with the toes attac hed to the distal e nd a bird walks onlts toes only, k eepi n g its heel o ff the gro und A bird s le g a nd foot, lik e the wing, have bee n stru cturall y l ight e ned. The femur lik e t h e humeru s r ece ives a n a ir sac from the respi ratory system. The toes and most, i f n ot all of the tarsus have onl y a thin scal y c overing. Movements of the toes are co n tro lled by tendons exten din g f rom muscles in the crus. If you have a live bird or a freshl y kill e d specimen slowly exte nd its hind limb to full length, then flex it close to the body w hil e watch i ng t h e movem e nt of the toes. You wi ll observe that when yo u extend the limb the toes ope n and when you flex it. the toes close into a po s ition for g rasping. The toe s close because of t ension p laced on the tendo n s as t h e heel bends ( fig. 1 14 ) When a b ird squats on a perch to s leep, the toes t hu s auto m at i c all y grip the p e rch a nd stay lo cked o ntu it until the bird awakens and stand s up. in Bird Form Now that you are f a miliar with the form of a bi r d a nd have become a c quaint e d with the names for the diff e r e nt parts, you are pr e par e d to take a broad look at the ways bird s differ f rom one a nother i n form and appearance. This step is essential before l e arning h ow bird s a r e classified a nd n a m ed. A l thoug h the ability to f l y imposes cer tain r estrictio n s on s ize and w e ight the range in birds i s astonishing-from the male Bee HumBird Bialoeq 1-15 Figure 1 12. Primitiye Fool: The feet of the earl iest terrest rial veHebra.tes / tad five f orward-point in g toes, numbered f'rom m ed i a/to lateral. T h e mosU toes of birds am thought to co rrespond to toes o n e throu gh fuur of these vertebrates. Figure 1-13. Osttich Fool: 11'1 man)' fast running a nimals, natural sel ec tion has rerluc e rl the surface area contacti n g the grounci .Just as the feet of horses are r e duced to hooves, the feet of Ostri c hes are redur;ed to two shan stout toes, one poorl y deve l o per/. O n the {lottom s of both toes a r e sof t e lasti c pads, whi c h pre venit he feet from sinking in t o soli sand. The f/igiJlless Ostriches rely on t h eir dbi/ i t y to m aintai n a steady runnin g uf abo ut 3 / m iles ( 50 k m ) per h o ur-to escape preclatOI'$ in the open savannas .wd deserts of Airica. From Birds : R ead ings from Scienti fic American edi1ed b y Barry W. Wl/su11. Cop yrig h t 1980 b y W. H Freeman Jnd Company Used with permission. I


1-16 Figure 1-14. The Mechanics of Pt!rch ing: In the legs of IJ'ee-dwel/ing birds, the tendons from certain muscles ext end down the leg behind the ankle to attach to the tips oi the toes When a perched bird bends its ankle to lower itself on t o a branch, the bending automaticall y creates tens io n on these tendons which pulls on the toes, forcing them to close around the bra n c h. Thus, when the bird is at rest. its toes tightly grasp the perch. From Birds: Readings from Scientifi c Ameli can, edited by Barry W. Wilson C opyright 1980 by W. H. Freeman and Compan)'. Used with permission. K,evirlJ. McGowan mingbird with a wingspan of 2.6 inc hes (65 mm) and a weight of less than 1/14 ounce ( 2 gm) to the Wandering Albatross with a wingspan of over 11.5 feet (3.5 m) and a weight of as muc h as 19 pounds (8.6 kg) (Fig. 1-15). The heaviest birds c annot fly; the flightless Ostri c h may weigh 345 pounds (156.5 kg); the Emperor Penguin, 100 pounds ( 45 .3 kg). The heaviest of flying birds -the Mute Swan, Wild Turkey, Kori Bustard, and Great Bustard-weigh up to 20 to 30 pounds (11 to 1 5 kg), with extreme individuals of the large bustards reported up to 44 pounds (20 kg). P erhaps because of their adaptations for flight, all birdsare similar in general configurat1on, and a ll are immediately identifiable as birds. Within these general limit s the externa l form of birds varies widely, reflecting lheir specific adaptations both to the habitats in which they live and to their methods of acquiring food. The following sections describe some of the mo r e common variations in the bill wings, tai I, and feet. The Bill The bills of birds have different shapes for reaching, picking up, and manipulatingdifferenttypesoHood (Fig. 1-16). Bills can b e short, Cornell Laborator't


Chapter 1 I ntroduction : The World of Birds a. De cu rved Bill White Ibis b Tubular Nostrils Sooty Shearw.1ter Figure 1-15. Bird Sizes: Birds m11ge in sfze irom the liny male Bee H um mingbird with a o{2.6 inches (65 mml to the Albatross with a ' 'ingspan of over 11.5 (eel 135 mi. Here, a hummingbird perclws o n a flight feather from the wing of a l,1rge hi rd. b y Charles L. Ripper c Spoon-shaped Bill Spoon!> ill d. Cross ed Bill R'ed Crossbill e. R ecurved Bill American Avocet ----Figure 1-16. Bill Diversit y : The bills of bird s have been m olded by natural selection Into a great vari e t yol'shapes Mdsizes each s uit ed t o a patticular foraging s trategy. In adclilion to gatheri11g food bird s use their bills for fending off predators co urting, nest building and preening. a. Decurved Bill ofWhite Ibis : 11Je Whi t e Ibis uses ils long, decurved ( downward curved) bill to probe mud and sand for invertebrates. It also sweeps its bill /rom side 10 side i n the mann er oi the spoonbill (see c ) b. Tubular Nostrils of Sooty Shearwater: Many birds that spend much of their lime at sea, and thus must drink sillt water, h,we their nostrils at the ends oflung tube s on top of the bill. These tu bular nostrils help with the elimination of excess s.1/t (see Fig. 3 '-34b). c. Spoon-shaped Bill o(Spoonbi/1: The s poonbill sweeps its brood. IJi/1 through s h allmv water (rom side to side In search for small Jquati c a n imals sud1 as crustaCl!'a and moti(Jsks, In murk y walt!li !Jnwevet, the s('oonbi/1 sweeps its bill just abrwe the bottom the c urv e d dorsal and llat ventral surti1Le5 creutin g swi rlin g currents that pull prey up n(( the bottom .we/ into /he water, where the y can be captured mor e eilslly. d. C rossed Bill of R ed Crossbill: The crussecl tips of c rossbill bills allmv them co efficienl/y pry seeds irom cleep within open ur cones alpines or other conifers. e. Recurved Bill of American Avocet: n1e American Avocet swc'l.'ps itS long, sensitive recun t cd ( up ward curved) bill from sicleto si de in w,1ter, in a simi/or manner to that of the spoonbill. Or.nvings bv Charles L. Ripper. Handbook of Bird I


I 1 -18 Figure 1-17. Wing Diversity: Wi11gs have evo lved a tremendous diversity of shape. e<1clr suited to a different fli[1111 style The four examp les h e r e are viewed from above In a and b the curves labeled "wing curvowre are cross sec/ion$ throveh the outstretched wing from the leading, cranial edge (thicker part uf curve, at /efl} to the trailing, caudal edge llhinner pJrt oi curve ill right ). nley r epresen t the curvature or th e top and bottom surfaC'e5 of the wing. a F lat W ings of a Swallow; Swallow wings h ave lillie curvature and ,1re considered flat. b. Co n cave W ings ol' a Grouse: Grouse wings are c urvet/ l>elow, and are cons idered concave c. Round Wings of a Hawk: In somt.> hawks, the middle primary feathers are thf! longest, creati ng a rounded wing tip. d Pointed Wing s of a Gull: In gvlls, the outermost primal)' featl1ers are the longest crea(ing a pointed 1\dng. Drawings b y Charles L. Ripper, a. Flat Swallow Wing Curvawre Kevil! J McGowan long, stout, th in pointed, or blunt. Bills may curve up o r down, or may b e faintly or conspicuously n o t c h ed, spoon-shaped or crossed. Bills c an b e specia l ized for culling flesh, filtering sma ll organisms from water s t abbing grasping, hammering, picking up small i nsects, or opening large, hard f ruits ( see Ch. 4, Oral Cavity Bil l). The nostrils ( nares ) also may have vario u s shapes: oval, cir c ular, or slit-like; sometimes they have bony tubercles in their centers or are loca ted at the ends of e long a ted tubes; sometimes they lack a septum between the two sides ( you can l ook in one and out the other!); and sometimes they are surrounded by a fleshy ce re or overarc h ed by a fleshy operculum (see Fig. 3-34). Some birds, such as boobies and gannets lack ex ternal nostrils altogether. I n some cases the funcl'ion ofthepeculiari ties is known ; in many cases, it is not. Nostrils and their various forms are discussed further inCh. 3 Th e WinBs The wings are co nsidered l o n g when the dist ;mce from the bend of the wing to the tip is longer than the t runk of the bird, o r short when thi s d i stance is the same or less. W i ngs are round ed when t h e m iddle primaries are longest or pointed when the outermost prima r ies a r e longest. They are cons id e r ed narro w when a ll t 'he remiges ureshort, or broad when a ll the remiges are long; concave when the curva tur e of t h e win g's underside is extreme or flat when the cu rvature is unusually slight (Fig 1-1 7). b. Com: ave Grousp c. Round Hawk AL}. WINGS VtE\t\ I ED FROM ABOVE d. Pointed Gull Cornell lnborator't of OrnitholoBtf


Chapter 1-lntroduetion; The World of' Birds Theshapeofbird s w ings is not arb itrilry-each is suited t o its own specific purpose. The s h ape of a win g directly affects the way a bird can fly, affectl ngsu ch things as t h e amount of I i fla .nd drag that the w in g cre ates when moving through the air. Lo n g, n a rr ow, poi n ted wings are best s u ited to l o n g distance flyi n g and soar i ng over the seas; long, b r oad, round ed win gs to l o n g-dista n ce f lying o r soaring over l and; s h ort, rounded wings to sho rt fli ghts in forests and fields; rounded concave wings fo r qui ck take-off and rapi d escape over s h ort d i s t ances; and poi nted, flat w ings for quick win g acti o n a n d swift fl ight. Wing shape and its e ff ec t on f light i s d i scusse d in more detai l i n C hapterS. The T ail Th e tail is cons idered long if i t i s obvi ously l onge r than the t runk or short if i t I s the sam e length or shorter tha n th e trunk. I t i s practica l l y absen t I n a few birds, s u c h as g rebes. Usually the t ai l owes its shape to the r e l a ti ve length s of the r ectrices and the way they term in ate a t the trailing margin ( Fig. 1-18) Thus, the t ai l i s square at t h e e nd if the rectrices a r e -sl ,inned llawk Ha11dbook of Bird BioLogtt 1 19 Figure 1-18. T ail Shapes: Like lleaks a nd wings, bird tails come in a variet)' of and lengths. Although the fun c tion s of different tail shapes are 110/ Well Ullclerst oor/ th e llJiJS O( birds Me important in (light and various t ypes o f displays Tail shape is c/el(!rminod by the r e l ative letJgths a nd sh,JfJ<"'S or the reclrices (lail feathers) All t,JJ/s shown /1ere ilre viewed from below. a. R o und ( Ameri can Crow): become l o n gor fmm th e nutsicll' in (1.11 f:!rOI (O merli ill) b Graduated ( Blackbilled C u ckoo ) : rl1e rectrices become obruprl y l o nger tiom the outoide in. c. Forked ( Common T ern) : nw rf! ctrit:es become .1bruptl y /onxer fmmthe I n side out d. Point ed o r A c u te ( Rin g-necked Pl1easant>: nu.> m iddle rectrites are much longer t/1an the oThers. e. Emar glnale or Notched (Pine Siskin): The r ectrices become slighlly longer {rom tire insldt. m11. f. SCJuare (Sharp-s hinned Hawk): The> r ectriccs J r e dll ,1hout th e sam e length. by L. Ripper. c Forked lummnnTem


1-20 Figure 1-19. Formso flhePod otheca: The r o ugh skin CO\terin g the te r med the podotheca, has different forms i n dlffetent !)'pes of birds. The fun c tions of these forms, if any, remain unknown. a. Booted (Thrush): 111 thrushes tile podotheca is smooth, divided ii 110 l ong, continuous nnn overl appin g scales. b. Scutel/ate (Tanager): tn must birds with bare legs, s v c h as tile songbirds, the podotheca is broken up Into overlapping sc:-

Chapter 1 1 ntroduction: The World of Birds TYPE OF FOOT Anisoda c tyl Elegf!nl Trogon Belted Kingfisher Chimney Swift TOE CONFIGURATION { Ri[Jht Fool) v 0'0 v 0"0 I \ )_ Ow/sand Os pre ) Harulbo9k of Bird BioloB.'I 1.21 Figure 1-20. Toe Arrangeme n ts: Af though most birds have four toes, their <1rrangement differs among different group s of birds. Most birds including nearfy all perr;hing (p

I '1-22 a. Lobe d Toes of Cre b e for S w immin g Kevi11J. M cGowcm is reversible-the bird can use it pointing forward or backward. Only trogons have heter o dactyl feet, with th e second to e reversed. I n t h e p a mprod acty l feet of some swifts, all i o u r toes, i ncl u d i ng the hall ux, poi n t fo r ward. Swi fts can use thei r smal l feet as hooks to han g fro m the insi de walls of chimneys, caves, a n d hollow trees. In addit i on they can grasp p l ant material or nest materiJI with a latera l pln cer like mo tion1 usl n g toes, one a n d two again s t toes three a n d fou r Kin gfish ers have t h ree toes fo r ward and one behind bur the i r feet are termed syndact y l because the inner and m i ddle toes are united for much of their length-t he e c ological advantages, if any, of thfs a rr angemen t a re not k n own. Mouseb i rds (Coliidae)-small long t ailed African b irds-have highl y versatile i eet whi ch ,,I t h o u gh often classified as pamprodactyl, can a c t u a ll y be used i n iJ variety of configu r ations: a l l four toes pointed forward toe s o ne and four po i nted bock or <\ny co mbination i n between these pos i t i ons. T h e form of the feet of many b irds dearly suits the i r and enviro n ment ( F i g 1 2 1 ). Havihg one or two toes reversed he l ps a b i rd to grasp perc hes, b u t a n isodacty l zygodactyl, a n d h eterodi!ctyl feet b W e b b e d Toes o f Pelic a n fo r S wimmin g d S tout Toes and Strong, Blun t o f Crouse for Runnin g and S cratchin g c. P erc hin g Fool o f C r o w e L o n g Hallu x Claw ofLark Figure 1-21 F oo t Oi1rer si t y : The form of a bi"J's foo l r eflocts its b e havior and habital. f-eet m o d ified for a large surfacli! area to pu, (d) that s pend a g reat deal of time on the gro und ofte n running Jlld .

Otapter 1 -/ntroduction: The World of Birds all seem to do this equally well-so a n y ecologica l advantages that the different toe a rr a ngements m i gh t confe r remai n a mystery. Toes ior perch i ng in trees, climbing, capturing prey and carry i ng and manipu ICenrlin!l a tree trtmk. The \ also IJr.Jce the wnnrlpedw 's bod) while drumming. nest c.witl, or peckiog /i)r in>ecL<.JIIuwing the head c1nd necA In patmd t trte trunA. Althouflh it (/11111l> tm flues and ncst L.J"ities, thP Northem Flicker primaulv on lite ground, t OI1Stlllling ants ,111d IJI'etl/i's. Pl1oto cuuriC'SI u1 tsidor lekli11ICLO. Figurf' 1-23. Bam Owl Facial Disc: \ s nocturn.JI prt>d.uws. owls rf'!) he,w il) 011 ll l's se n sitive /waring b) iocusing sounrls into thec.1ropt 11ings, 11 hich .tre loc.w:cl posterior to the ere; l'hoto n/ 1. Rn/Jert WnorlwMrliCLO.


1-24 KevinJ. McGowan may be greatly lengthened and modified to form conspicuous plu mes or adornments (birds-of-paradise, peafowl). The colors of feathers not only enhance adornments but quite obviously provide color patterns that characterize different birds. Thus, some birds have spotted plumage, others, streaked. Some birds have color patterns that make them inconspicuous whereas others have gaudy patterns. The same species may have colors that conceal it on its nest and other colors that it uses to attract attention when displaying. A l though birds may seem to have feathers growing from all parts of the body feathers in most birds grow from tracts separated by bare areas. The bare areas are usually concealed because the feathers from the neighboring tracts overlap and hide them. Feathers and other external features of birds are discussed in detail in Chapter 3 InternaL The diversity of birds is no less apparent in their internal sys tems--skeletal muscular nervous, circu l a tory, respiratory digestive and u rogen ita I. Indeed, some birds differ more sharply internally than they do superficially thus providing a sound basis for distinguishing them. The internal anatomical differences among species are dis cussed In detail i n Cha pter4 DiversitLf in Bird Movement Birds are masters of the air but many of them also move quite well on land: walking hopping, or running on the ground; or climbing in trees. Many species have become proficient around water : swimming, diving or plunging for food. Here, the different methods that birds use to move on land and in water are briefly discussed. Bird flight is explored at length in ChapterS Movement on Land The first birds were probably tree-dwellers; when not flying from tree to tree, they moved from branch to branch by hopping-that is, moving by a series of fumps with feet together. later, some of the tree dwellers such as woodpeckers and creepers, achieved an ability to c l imb by hitching themselves up using their tail feathers as supports, or, like the nuthatches, by jerking themselves up at an angle. or climb ing down headfirst, keeping one foot high for suspension the other low for support (Fig. 1-24). When many birds left the trees for life on the ground, they began moving by walking and running-moving the legs alternate l y The changeover from hopping to walking and running was gradual, and gradations still can be seen. Among the cuckoos, for example, are the awkwardly hopping, arboreal Yellow-billed and Black-billed cuckoos, and the fast-paced, terrestrial Greater Roadrunner. Although most passerine species still hop much of the time crows and the European Starling ordinarily walk ; adult larks, pipits and wagtails walk and run Cornell Laboratorlj of


Chapter1-lntroduction : Tile World of Birds 1 25 Down>' Woodpecker Wllite-6rell$t"d Nvr!Jntcll Brown Creeper b uttheirfl edgli ngs hop; and theAmer1can Robin hops, walks, and runs between pauses when foragi n g for e,Jdfir s t ot)e n keeping one ion/ hig h for suspension a,nd tll r other / Q\V lor s upp ort. since thf'ir tails Jrc not moclitlecl t o act J> props Th .. t /a\o\1 ot thei r is largrr muf morf! Strongly curved 1/Mtl lilf' claws of their f orwardtal'S providing the strong grip thM the m t() cle;cend l1eadllrst. Or diVi n g> 1-JI' Rober t (';il/mm:


1 Figure 1-2.>. M ove ment o n th e G round: The firs t hirdsprobablylived in rrees, flyI n g or hopping from to bl'anch. As some birds adapted to life 011 the ground, they graduallr evolved irum hopping (movi n g hoth fells ilt the sam P timel to walking or ru nn ing /movillJJ th e legs For e..xample.. the GreJter RoJdrunller runs quickly along the ground but when i!s a rbo real rela lives-Yellow-billed and Bli tCk-bil/ed cuckoor;-venture to the ground the) hop. Althovgh passerines hop t/le Europrsm Starling w.1lks when on tlw ground. Mosl birds either hop or walk and run, bUt watch iln Amerkan Robin for ,my length of time ilncf you will no doubt see that it uses ,1 comiJfnatlon of ntovements ; wal/y Roi.JerrGillmor. Figure 1-26. Watki n(: in W a t e r : Some birds-especially h erons. cranes Ump kins and a numberoisllorebirds-have long le ss for waditJ8 in w.11er; l/Je length reflecting the water depth in which they m11y feed. The Great Blue 1-leron with its lotJS less a n d neck, sra/ks iis!J in shallow water, lwl sometlmt>s wades belly c/f:(Jp alon8 the shore{[nes o( OC'eans, as well as freshwater lakes, 5/reams, ,md marshes. TI1e Black-necked Stilt, with sQmWhiJt s/JO(ter legs, favors s h allower water and flooded fields where it searches mainly (or aquatic in sects. Other birds notahl) jacanas and some rails, have lnf18 toes that distrifJute tltefr weight over a large suriace atea f ike snowshoes, allowing them to Wiln across muddy areas and rto.11ing taliol] such as lily pads. Tht Northern jac.1nn, like other jac.anas. h.1s long clllws as well JS lnng toes. Dr;Ming b y Robert Gillmor. J "' ...,. ... "'="" .....-Cre,Jfer Roadrtmner furopean Starling Great Blue Heron Still Cornell Laboraton1 of Omitholuett Kevinj. McGowan Americ;rn Robin Nw1hern /acana


Chapter 1-lntroduction : The World of Birds a. Walking b. Tobogganing Handbook of' Bird Blolo[j'l 127 Figure 1-27. Penguin Locomotion on L an d : The flightless penguins highly specialized for swimming, move aw k wardly on land a. Emperor Peng uin Walking: Because /he penguin s feet ate set way back on its body fo ,,;din swimming_ it is limited to walking upr ighc, wich a s low, s hufflin g gail. b E mperor Peng uin Tobogganin g: When they must move quickly o n land, penguins r esomo tobogganing on their b ellies, p ropelli n g their torpedo-shaped bodies across the snow a nd ice b y vigorously beat ing t h eir stubby, flipper/ike wings as well e usee/like small hooks t o clin g to vertical surfaces of chimneys, trees, barns, and ocher scructures. Swifcs canalsomovecoes 1 and2 agai nsccoes3 and 41 pincer lik e lsee Fig. 1-20), to grasp plants and nest materi11l. A lthou gh they once nesc ed primJrily in h ollow trees, an increasing numb er of Chimney Swifcs now nest and roosc in chimneys. Ac dusk on a lace summer even ing hundreds of C h im ney Swifts may g.11h er 10 roosi in a sin g l e c himney. Photo courtesy of Michael Hopi ak/CLO


1 Forward Stroke Fig ur e 1 -29 H o rned G r e b e S wimmin g : To increase the surface il rea that pushes again s t che water, m a n y swimmlhg birds have eit h er webbed or lobed toes. Ccmts and g r ebes , s ud\ as the Horned Grebe pictured herl!, hove lohed coes. Th swim they m ove their legs alternate l y as i n walking O n the b ackward stroke, w hich generates power, the l obes push the bird forwarcllikeoarsorp.1ddles. On the fonnrd r ecovery st1oke t h e lobes of coots arrdoldec,l and the foo t of grebes is turned. both .1ction s presenting the least possible Jmaunl of resistance to the wa c er DrtJwing by Robert Gil/mor. 8Dckwarrl Scroke Backward Stroke M ovement in Wate r K,evin J. McGowan Forw11rd Stroke A l though the ancestors of b irds were terrestria l a n d most birds still depend .on l and for nesting, many species have adapted so strongly to an aquatic existence t h at t hey spend m u c h of their time swimming. A great n u mber a lso dive. Most birds swi m by a l ternate ly moving their feet in the water Swim m ing birds commonly are aided by eit h e r webbed or lobed toe s a lthough some birds such a s moorhens and phalaropes, are eKcellent swimmers despite havi n g n o speci a l toe modif icat ions. Both webs and lobes act as paddles p u shing against the wat e r on the ba c kward (powe r ) str oke then fol d ing or turning to r e sist as little wate r a s possi b l e on the forward ( r ecov ery) stro k e ( F i g 1-29 ). T he size of !he feet in proportion to bod y size is commens urate with the impo r tance of sw i mming in a bird's life. Stormpetr e l s have s n1all feet because they swim infrequent ly; co nversely pe l ic ans have e n ormo u s feet because t he y spend much of t heir t ime swimming. I n most birds, swimming is f u rther a i ded by broad, almost raftllke bod ies g ive stability, and b y a de nse feather c oat that holds a i r for buoyancy. Swimming is t h e pri ncipal movement i n the water for a l b at r osses, shearwaters, pet r els in t h e genus Pterodroma, gulls a nd oth e r aquatic scavengers, a n d phalaropes-a l l of w h ic h gather food on or just below the water s s urface B u t mor e than swimm ing is requi red of bi rds that obtain food u n der water Swans, geese, a n d the dabbling d ucks-teal, Mallard Northern Pintail Wood D uck, a nd so on-ti p up in shal low water, reac hing dow n to forage on the bottom (Fig 1 3 0 ) Osprey, B rown P e li ca ns, boobies gannets, and p lunge into the water from the air gai ning momentum as they descend. The h eigh t of t h e d ive depe nds on thei r size and the depths to be attained. T he heavy bodied gannets may p l ummet from 100 feet (30.5 m ) to reach dept h s of 10 to 1 2 feet (3 to 3.7 m). A n adaptat i o n consist i ng of many minute air sacs u nde r the skin acts as a s h ock absorber w h e n t hey strike the water. The lig hter b odied ter n s p l unge from o n ly a few feet, beca use they go n o deepe r t han a few in ches (Fig 1 3 1 ) Cornell L.aboraton1 of' Ornitlwlos'l


Chapter 1-1 ntroduction: Th e World of Birds --Tundta Northern Gannet Tern Handbook of' Bird BiolO[jlj 1 Mallard Figure 1 -30. Foraging in Water : Birds search for food in water in <1 number of differ<:tll w<1ys. Swc ms, S<'h. or oth ers mit// aquati c ,wimills. Stldacediv ers include penguins shearwaters, div ing-petrels, loons, grebes, cormorJs, mergansers, alcids coots. and t/Je diving ducks"-su rh as the Lesser Scaup illu:;trated h ere, Draw i ng b y l?ohert Gillmor. Figure 1-31 Diving from Air : Man y I?Trds plunge dive into water from t),e a ir, the height of th e dive depending on the bird's .Jze a nd the depth to be Jrtained The heavy-bodied Nort hern Gar)lle l scans for schools oi fish il!ld then may plummet from as high as 100 feeL (J O . 'i m ) to reac h underwater depths of 10 r o 7 2 feet !J to 3.7 mi Tbe tern from nm c h lower, barel y going below the wat ers surface. Terns hover i n place before diving. watchins far fish near the surf.JCe. Osprey, Brown Pelicans, boobies <1nd kingl/shers also dive into water from air Dmwlng by Robert Gillmor.


1-30 Kevlnj. McGowan 1\ret/c Loon Figure 1-32. Swimming Underwater: Birds speciafi.tcd for underwater swim ming haw streamlined torpedo-shaped bodies With rile feelloc;ated far back on the body. In this position, the (eet can generate much power and also act as et: fec/lve rudders. Loons, grebes, cormorants, anhingas, .1nd use primarily thair feet to propel themselves through water. Merg.msers and diving ducks, in cluding tile Longtail ed Duck, may use just/he feet whi l e forJBing a lop g the bot tom, keeping their I.Vings at U1eit sidl:!s, but trse both winos and feet to swim to great depth $ Althc>ugh they usuall y feed within 39 feet ( 9 m ) of the surl'ace, Lung-t ailed Ducks have been observed as deep as 200 t'eet-deeper th.1n any other duck/ Penguins, ho!Atever, are the c h ampion avian divers. Like alclds shearwaters, and diving-petrels the y use o nl y their slort pac/dle-lik'e wings to ny through the w.1ter. They regulnrly forage at depths o(65 teet (20 m J or more the large Emperor Pel)guins goins as deep .1s I ,752 feet (5J>

Chapter 1 -/ntroduction: The World of Birds Not surprisingly, the master divers of t h e bird worl d a r e the penguins Many spec ies regularly clive d ee p er tha n 65 feet (20 m ) T h e two l a r gest spec ies, the Empe ror a nd Kin g penguins are the undisputed champions. T h e large King Penguin has b ee n recorded ( w ith d epth gauges) to dive up t o 1 ,059 f eet (323 m), and the even larger Emperor P e n g u i n has b e e n r ecorded to a f a ntasti c 1 752 feet ( 5 3 4 m). Even t h e s m a llest pe n guin, the L ittl e Pen guin of Aust r alia, w hich n ormall y d ives to less than 6 feet ( 2 m ) has been recorded diving to 88 feet (27m) To dive th i s deeply penguins can ho l d their breath for long periods, up t o 1 5 8 minutes for the Empero r Penguin, whic h re gu l a rl y stays und e r water for 2 to 4 minutes Bird s clivi ng for s u c h long periods actually stay underwater longer than would be predicted by theamountofoxygen in their bodies. Pen g u ins h ave a numb e r of c o mpl ex physiologi c al ad ap t at i o n s not a l l com p l ete l y understood that allow them to acco mplish th ese l o n g a n d d e ep dives. A few other birds not water bir ds per se, explo it the food r esources of inland wa ter ways by expe rtl y diving or swi mming. The B elted Kin gfisher is ski l l ed in p l u n gi n g for fish a l tho u g h it cannol" swim; th e American Dip p er residing a lon g swift m ountain strea m s in western North America swims-actually fl iesunder wa ter a nd wa l k s o n the stream bottom to take i nsec t l a r vae attac hed t o ro c k s Neither species has s p ecial izati o n s for maneu vering i n water. One more uniqu e wat e r-r elated behavior is often observed and is worth no t i ng When mildly a l a rm e d s om e gre bes, part i c ul ar l y Pie d-bi ll e d Grebes ma y sque e z e air from th eir feat hers a nd air sacs, thus i n creasing their density, and slowly s in k stra i ght down into the w a ter (Fig. 1-33). The y m ay rem ain compl e t ely s ubm e r ged o r with the eyes j ust peering out across the w a ter, unt il a ll danger has passed. Ofte n birds c a n capably perform c ertai n m o v emen t s t o whi c h they are not primarily adapted. Ducks and gulls h av e w ebbe d fe e t and cools l o b ed feet, f o r swimming, ye t these birds ca n fora g e success fu ll y o n d r y l a nd far fro m wate r Under compelling circums t a nces, pr slow ly sink ing strai g h t t luwn i nt o r/w 1\', 5ometi me5 re main ing comple t e l y tmderwa rer, some r imes l eavi n g th e n ec k Mid bud\ pall/) visi h le a n d so m e t i m es l e a v ing justtl u" Cc')'t'S a n d nostri l s iiJIJove r ile surface, t o c hec.k fo r d a nger. P h o to 5 IJyTom Vezo


1 K,evinJ. McGowan NaminB and Classification of Birds HaveyOLI ever looked i n a f i e ld guide and wonder e d why clw brightly col ored orioles and meadowlarks are a ll lumped together in the same family ( lcteridae ) with the mos1ly black grackles and Red-wingeci Blackbirds whereas the soot-black starli ngs and crows are not? Why are the coots put in with the ral l s and cranes and not with the ducks, which they resemble so much when swimming around in a pond? Why are the swifts and swallows that look and act so simi l ar not listed together? And w h y a r e the cra nes on different pag e s than the similar-l ooking herons ? What these simpl e questions really translat e to is "How, a n d w h y do peop l e classify birds?" At least sinc e Aristotle (384 to 322 B.C.), and p robabl y from time immemorial people h ave been giving names to b i rds and trying to put them into logical groups, that is, making classif i ca1ions (Fig. 1-34 ) Humans love to put things into pigeonholes whether they go easily or not. Exactly how people ar r a n ge birds into categories however de pends o n what t h e catego r ies a r e supposed to represent. For example, in some primitive soc i eties birds might be d i v id ed into two groups: edible and inedibl e (Even t.oclay some peop l e tend to think of "useful and ' harmful'' birds. ) Aristotle and other ear l y Western thinkers trying to group s imilar" birds based their classifications on such things as habitat ( for examp l e water versus l a n d), l ocomot i on, food habits, and obvious p h ysical characters ( for example, bill s i ze and shape ) .Aristotle divided birds into three c ategor ies: those that I ive o n l and those that live in the water and those that live at th e edge of wate r I n the mid 161 h century Pierre Belon fo llowing the ideas of A r istot le, class ifi ed birds into s i x g r o ups : raptors waterfowl with webbed feet marsh birds w ithout webbed fee t terrestrial birds large arborea l birds, and small arboreal birds. ( His classification lumped Ostriches chickens and larks into the same terrestria l ca t egory! ) Morphological characters (t h e actua l form of body structures ) were first used as a basis for clas sifi ca ti on by Francis Willughby and John Ray in 1676, and their work was o n e of the pri mary sources used in t h e mid 1700s by a Swedish natura list, Carolus Lin n aeus in his classifi c ation of animals the S ys tema Naturae, discussed in more detail later i n this c hapter. Various systems of classif i cat i on based on differing ideas of habitat, be h avior and ph ysica l simi l arities floated a round for the next hundred years or so, with no c onse nsus on what to r e prese nt. With. t h e understanding of l;:!volu tion by natural selection as e xpounded by Darwin in 18 59 (Side b a r 2: The Evolution of an Idea: Darwin's Theo r y ) the class ifi cations based on so m e vag u e natural" or l ogical" orde r wer e replaced with ones-that grouped organisms be c ause of common ancestry. In other words, o r gan i sms thought t'O be r elated to one another were put in the same group. The classiii c ations, ther efore were a n attempt to represent the phy l oge n y or evo luti onary history of birds. (Note that t axonomy is the c l assif i cat i on-assi g n ing names and -----------------------Cornell Laboratorl.f of Orn!tholof]IJ


Chapter 1-l n troductlon: The Worl d of Birds Fi g ure 1-34. Si gnificaniSie p s in th e History of Bird Classific a t ion 384-322 B.C. Aristorle groups birds into threecalegorfes: rhose thatlfve o n land t hose t hat live in water and those that l ive at t he 12dge of water. Mid 1 500s Pierr e Belen separates birds into six gmups: rapto rs, waterfowl with webbed feet, marsh birds without webbed feet, terrestrial bi rds, lar ge arboreal birds and small arborea l birds. 1676 Franci s Wil lughby and John Ray are the first to use morphological char acters to classify birds. Mid 1700 s Carolus Linnaeus devises system of binomial n ome n c l ature for classi fying o r ganisms. 1859 C harles Darwin p ublishes his theo1y of evolution i n his b ook On the Origin of Species by of N,ltllral Selection. From th i s time on, resear c hers t ry r o classify birds based on com m on ancestry. 1888 & 1892 Maximilian Furbinge r ( 1888) and Hans Gadow ( 1892) each dev ise modern classif icaUons of birds based on a host of anatomical cha r acters. For the f irst tim e a l l pitsser i ne songbirds i)re grouped together, swifts are separated from swall ows, and cuckoos are separated f r o m woodpeckers. 1 -33 19301960 A l exander Wetmore uses new i nformation to adjus t the classifications of Gadow1 inclu d i ng organ izing the songbirds. Wetmo r e's publ icat ions a r e respons i b l e for the ordering of groups found in most American tield guides. 1980s Charles S i b ley and Jon Ah l quist propose a major rearrangement of the orders and families relationships-of organisms, whereas phylogeny r efers to t he actual evolutionary relationships that the taxonomist h opes to represent. ) Just what characters rouse and vvhere t o draw the boundaries have been, and continue to be, subjects of grea t debate. The f ir s t modern, evolutionary classificat i ons of bir ds were pro pose d b y Maximi l ian furbinger in 1888 and Hans Gadow in 1 892 based o n a host of anato mical characters. Finally all the songbirds were grouped together and t h e swifts (because of such featu res as their u nusual wing struc tu re) wer e separated f rom swal l ows, and c u ckoos f rom woodpeck e r s Subseque n t bird classif i catio n s wer e heavily based o n these works, and few major c h anges were made in th e first half of the 20'h century. Especia lly relevant is the work of Smi th son i an r esearcher Alexa nder Wetmor e. A lthough his classificat i ons published between 1930 a ncl1960 differed litll e f rom Gadow1s h e d i d incorporate some new I n formation. H e a l so organized t h e so ngblr ds, a g roup that Gaclow vievved as uniform, and had left large l y undi ffere n tiated. Wetmor e's ( Continued on p. I.JIJ) Handbook of' Bird Bioloarl


1 34 1\e, i n J McGowan Sidebar 2 : THE EVOLUTION OF AN IDEA: DARWIN' S THEORY P o d ulka I n 1859 Charles Da1wi n rocked both the scientific and nonscientific wo r l d with his radical theory on how spe, cies overtime His book On the Origin of Species byMe.wsofNatural Selection set fort h t h e idea of evolu tion by niJtU r a I selectio n which remains a corne rston e of bio logy to this day. II addressed many puz.z l ing aspects uf living things, such as t heir tremendous diversity, their origins and rel ationships toone another t h eirs i m i larities a n d d ifferences, their bewi lder ing geograph ical rlist r i but ion,

Chapter 1-l ntroduction: The World of B i rds basis for natural selection: the individuals with the advantageous traits survive; i n essence, they 've been "se lected by natu re." ( 2 ) Some of th e variati o n b etween individual s i s h e reditary. A l though the i dea of r eceivi n g traits t hrough our genes is co m mon know ledge today / indeed, it is now "fact," r athe r t han "inference") Darwin lived at a time when nothing was know n about i n herita nce. He propose d his theory long before chromosomes and genes were discove red, and just before the work of G regor Mendel an Austrian m onk working with pea plants, prov ided the basis for modern genetics_ (;J) When more individual s with certain ( advantageou s ) trait s s urvive and r e produce, more of the a dvantageous traits appear in the next generation. Over many gener ations the c h aracteristics of a spe cies may change. T hrough t h i s process, evolution occurs. For examp le, ii ilying faster allows a Mourn i n g Dove to more easily avoid becoming a meal for il Cooper's Hawk, the n i n any gener ation of Mourning Bird Whale Fig ure A. V e rtebrate Fore limbs: The forelimbs of all vertebr.Jtes from the same basic bones, although the y halie been modified through natural selection to carry out widely different functions. In this drawing c orresponding bones are shaded similarly fore.1ch animal noticed thasimi/arity among verrebrate forearms, and reasoned that it must result from ea(::h beins modified from the same common ancestor. Oiherviise, if the slructures Were unrelated each "designed" from 5cratch, one would ha11e to aecept the unlikel y theor y that/he same hasic ser of bones was rhe best srarring poinl for 1 Doves, mor e of the fast er individuals should s u 1 vive and r e produce. If f l ight speed is hereditary, t.he next generation s hou l d have a greater percent of faster i ndividua ls, and so on. ( In evolutiQnary jclrgon the faster birds are said to have a greater fitnessthe likel i hood of produ c ing offspring thal will survive to reproduce relativ e to the others ; being f

1 Lyell, provided him with evidence that the earth was much older. Today we know that the pia net has existed fo r at least 4.5 billion years, and life of some form has been p r esent for at least 3.5 billion. Because natural sel ection often acts on minu te differences between indivi duals producing slight changes from one generation to the next l ong time spans are necessary to explain the kinds of changes evident i n the fossil record. How Natural Selection Act s Although species or populations evolve, natuml se lection does not act directly on them as a whole. Natu r a l selection acts on/yon individuals-each individual l ives or dies according ly-but it results in the evolution of populations and species. Furthermore, natural selection acts on the whole individual. Because each individua l is the sum of many d i ffe r e n t genetic traits, the re l ative advantage of each tra i t depends on its genetic context. For example, a trait increasing the growth rate of a tree s trunk and branc hes is useless, possibly even detrimenta l un less accompanied by a trait to increase the growth of the roots. The Source of Genetic Variation n)e variabili t y between indi vidua l s of the same species ul tim ately ar ises f rom mutations : actual changes in the basic struc ture of DNA. Muta t ions can a rise spontaneously, but also are i nd u ced by radiation and certain chemicals. Although mutations can occur i n any cell in the body only those in the cells t h at produce spe r m and eggs can be passed on to an individual s offspring. Over hundreds and t h ousands of generations, many mutations arise. Neutr al and advantageous ones may pers ist, while disadvantageous ones may die out. Over time much var i ability may be produced in a popu l ation (for exa m ple green, blue, and b rown eyes; blond, black and red hair) f rom neutral or near-neutral mutations. KevinJ. McGowan dation by Cooper's Hawks became a survival factor, or ( 2) a mutation increasing fl i ght speed arose randomly in a Mourning Dove, allowing it to more readily escape hawk predation. Once the var i ab i lity exists n atu r a l sel ection proceeds in a very n onrando m fashion but the type of variab ility that arises in the first p l ace is random The random nature of mutations explains why evo l ution is often so s l ow. Nea rl y all mutatio n s are detri mental. As Corne ll astronomer Ca rl Sagan explained to his students: "Think of any livi ng th i ng as a finel y tuned watch. What is t he chance that d r opping your watch will impr ove its function?" Natural selection proceeds s lowly because it has no predetermined purpose: i t is not goal oriented. Natural sel ect i on works on the random efforts of a "blind watchmaker' ( Dawkins 1987) but na t ura l select i on itself is anytl 1 ing but random. With lime, it can produce a m asterpiece of adaptat i on: from the colorfu l e l aborate feathers in a peacock s train to the sharp, fish catching beak of a Black Skimmer ( Fig 8). Natural se lection d i d not, h owever, have to produce anyth i ng l i k e bi rds or hu m ans both are the result of natural selectio n at each step along the way, mere l y respo nding to the conditions at hand. A key point. misunderstood by many people, is that mutations are random. They a rise by chance, not fo r a pur pose. In the previous hypo t h etical examp le, the variation in t h e flight speed of Mourning Doves did not develop because a need for faster birds arose but because either (1) by chance an array of flight speeds existed in the population before preFigure B Blac k S k i mm er F oraging: The beak of the rem/ike skimmers Is highly spe cialized for their unique fish-catching technique Wi(h its beak open a Black Skim mer (as pictured here ) flies low over a rivet or ocean its/ower beak slicing through the water. When it contacts a fish, it snaps the upper .mel lower beak together. grasping its prey light/)!. Natural selection has modified the /ower beak to a vertically narrow, kni(e-Jike blade which creates minimal friction as it moves through the water. It also contains many sensory receptors, allowing il ro detect precise!)! when a fish is contacted. Furthermore, the lower jaw can open widely to ,1/low the lower beak to penetrate below the water's surface in flight, while the upper beak also opens widely to avoid touching the water. Also see Figures 4-87 and 4-88. Photo by Tom Vezo. Cornell Laborator'l of Ornitholoe'l


Chapter The World of Birds The Effects of Natural Sel ection Natural selecti on does not always result i n c han ge. Some organisms, suc h as cockroad1es and h orseshoe crabs, h ave c h anged on l y s li ghtly over vast stre t ches oi geo l ogic time whereas others suth as mammals, have c h anged d r amatically. I f a species Is well adapted to its environment, natural selection ma y act against any mutation t hat woul d than ge it. For exa m ple, if Mourn in g Doves a l read y fly at th e optimum speed, seledion will act agai n s t mutations that would m ake that speed either faster or slower. This type of selectio n termed stabilizin g selectio n works to kee p t h e species at the o ptima l m idd l e point. Only w h en condi ti o n s change ( for example, Couper's Hawks become less abunda nt ) a n d the former tr aits are no I unger opt im al, does natur a l selection p r od u ce cha nges. When l iving things it i s easy ro for get that w hat you see is not a finished proc!uct. Natural selection i s a n ongo in g process that will continue int o t h e f uture, furt h er m odify in g the organisms a li ve today as conditions <.:h a n ge. Evo l ution ca n occur on several different l evels. The evo l ution of new s p ecies over thousand s of years is often Figur e C. Cooperative Breeding in Florida Scrub jays: Found only in patches ois tunted scrub oak in cenl r ilf Florida the threatened Florida Scrubja y has evolved il cooperalive breedi n g system. These jays live yeal for up to six year>, remaining with their parents as h e lpers. I n this photo a three-yearold daughter ton nest, at right) h elps to defend the nest oft he breeding pair (her four -ye ar-old stepfather, at top ; and her eight-year-old mother, a t/eft), 1ivo nest/ inss are visib l e beneath the !laughter. AI/ thr ee adt1fts have drawn near the nesr joining fnrces against the photographer. Helpers assist s ignifi cil ntl y with territory defense, nest defense, ilnd nestling cart?, increasing the chance of nesting success. Although h e lpers delay their own l;reedi118 to help, these long-lived birds may act uall y in crease th1Hr lifetim e genetic co ntribtllfons co generation s by doing so. The Flor ida Scrui1-Ja)''s habitat Is rare and patchy-the jays can occupy only those areas that recently have been burned by wildfire. AI a result nearly all suitable areas .ue co n stantly being defended vigorously by breeding birds. Thus. a new/) fledged male tmg scrub-jays th,lf disperse in their first )'ear face g reat rliftlculty mmpeting lor breedlniJ npporlllnities, ,md often die before su<..ccodiny. Besidl!s providing a safe "home has e. rl e l,lying I herr dispersal allows Ire/per> f()COntrii>Ute some of their own to fuwre generations by rearing their own s iblings (who have some of the same senes as the helper IJec.wse they share parentM, while the y wait for a c hance to l>ewme breeders tl1emselves. As remarka()/e as it mily seem. niilural can pro duce coo perative breeding systems even mme than the Flnril/,1 Scmb-/dy's, simp!)' because helpers bene tit m01eb1' helping their pare(ll,ii than the y WrJtlfcl by allempting to breed ear/ yon their own. Sec Ch. 6 Parental Behavior: Wfr) ,uethere Helpers at the Nest" that Care tor Snmeune Else's Offsp ring. Photo courtesy of J ohn W. Fitzpatrick. H a ruJbook of Bird


1 Figure 1 35. Classificat ion of Cools, R ails, and Duck s: For many years, coots were grouped with the ducks because, like ducks, the y swim on the surf.1ce and dive for food. Alexander Wetmore was th e first to r ec ognize that th e coots, with their long, lobed toes, medium-long legs, and s h ort thi ck bills should be grouped with th e rail s (see Sora photo)-who have simi/i)r characteristics (bu t wiJOse long toes are unlobed). Wetmore published hi s classifications between 1930and 1960. Coot and M alla rd photos by Marie Read. Sora photo courtesy of Lang ElliotVCLO. K evin J M cGowan publ i catio n s ar e responsibl e for th e order i ng of groups fo un d i n most Ame r i can field gu ides. For e x ample, as a resultofWetmore's work th e lob e foo t ed, s hort-billed coots are s hown w i th t h e rails and not with th e web-ioote d spatulat e -billed ducks1 whi c h t h ey most s u pe r f i c i a lly r esemble whe n swimming ( Fig. 1-35). American Coot Sora M allard Com ell La b oratorl.f of Ornitholo&tt

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Owpter 1 Introduction: The World of' Birds Althou g h a few odd r eo rganizations occasionally have be e n proposed, none has ga in e d much suppor t i n th e ornithologica l com munity. In fact. inertia has played a g r eat part in maintaining the classific a ti o n of b ird s throughout the pas t cen tury. Unless stro n g evide n ce to the con trary has been available bird relatfonshrps h ave stayed Just w h ere Gadow put them. Species get moved arou n d regu l ar l y and some fam i lies h ave emerged while others h;we been discarded but very l ittle movement of families amo n g o r ders ( the ne"1. category of classification above families see Fig. 1-41 ) has take n place. In the 1980s Char les S i b l ey a n d Jon Ahlquist p r o p osed a n e n trrely new a n d somewhat rad i cal phylogeny of b ird s Sibley had l ong bee n inter ested In the higher groupi ngs of birds a n d was a pioneer i n using chemicil l (instead of physica l ) metho d s to explore bird re l a tion sh ips. The studies of S ibley and Ah l quist r esulted i n the first major rearrang ement of the orders and families of the worl d's birds in n ea r l y hillf a ce ntur} Many of the relations hi ps th ey proposed wer e familiar (d u cks and geese still went together, as d i d hawks and falcons), many corroborated previous heret'ical rev i sions proposed by others (Ne w World vu l tures and co ndors a r e r eally modifie d storks and n ot hawks), and still others were surp r ising l y novel ( frigatebirds penguins, l oons, and tubenoses formed a group). Perhaps one of the most unexpected find ings was t h at-the numerous passeri n e land b ird s native to Australia were n ot r e lated to the warb l ers and thrushes th ey resembled but were related to eaoh other in a remarkab l y diverse array of forms at l east as spectac ulilr as the be ttef-known marsup i a l mamma l $ + Unfortu n ately, this work was not without co n troversy. Some of the r esu l t s wer e t ainted by s u specl meth ods and unexp l a in e d cor rection facto r s As a result, acceptance of the new o rd ering of birds has been slow and gua rd ed. Gradually other r esearche r s a r e testing t h e p r oposed novel relationsh i ps, and generally f inding co rroboration for most. II will take a while, however, for the dust t o sett le and for any ar range m ent of birds of the worl d to become t .miversally accepted again. The American Ornith ologists' U n ion, the largest body o f professional ornithol ogists i n North A m er i ca in its 7th ed iti on of the Check-lis t of North American Birds (commonly called the "AOU Check-list"), used the followin g p h ilosop h y regarding t a x onomy: "Because of w i de accepta n ce of the C h eck-list as an n uth oritat i ve standard th e Committee respons ible for lis preparation feels it necessar y to avo id hasty decisions that risk q ui ck r eversa l thereby foste rin g instabi lity .... Our general stance has be e n con servative and cautious when judgi n g recently published proposa l s for novel class ifi ca tions schemes of r elatio nship, and species I i mits .... The Committee estilb l ished a policy for this edltlo n whereby c hanges in classificat i on of major groups re quire concordant ev idence from two or more in depende n t data sets." In the future, as more of t he relationships a r e examined a n d more i n forma ti o n i s gathered, the p l acement of some species may change. Taxonomy i s not a static endeavor, but rather like much of science, ideas change as more information becomes available of Bird Bloloart '1-39

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1 Figu re 1-36. Con vergence of S w ifts and S w allo w s ; At fi r s t g lan ce, swifts a nd swallows are very similar in appearance. Speciilliied fot life in the air, they both h ave streamlined bodies ; long, pointed win gs; and s hort bills with which they capture ins ect!; in m idair. A closer exa m ination, however, reveal s many significant anatomica l differences. Swallows h ave a more sy rin x (v oice box) than swifts a different toe a rr ange m en t (anisodactyl compared /a t11e parnprodacty l feet of swifts lsee Fie. 1-20/), and different wing proportions. In swallows 'i h e wings are lon g as aresul l of the long radivs and v/na (in the or antebrachium ) whe reas the swift's l a n g wings result from an e longated manus !hand). These anatomical differences indi cate th at the s imila rities between the two bird g r oups are due t o convergence-the evolution of similar feawres in response to a simi lar envi ronment and lifestyle--rath e r than to commo n ancestry. Pirmprodactyl Feet (Four Toes Forward) S w ift Simple Syrinx KevinJ McGowan M e thods Use d to Classi fLf Birds Through the years, a larg e number o f physi cal char acte r s have been use d to classify birds Some of t h e obvious external characters, such as color, bill shape, and foot shape, have turned out to be of l ittle use because of the problem of c onv e r genc e one of the most troubling problems for biologists. Resear c her s now realize that some animals (and plants) resemble each other not because they are r e lated but because they evolved t o do the same thing; that is1 they independently develop e d a similarsolutionto a similar probl e m This pattern of e vo l u tion is called c onv e rgent evolution For example h o rses and ante l ope both have long legs not because they cam e fr o m the same a ncestor, but because they both use the strategy of runnin g fast t o escape predators, and l ong legs are good for that. Both swifts and swallow s have long, pointed wings and short bill s because they both chase fl y in g insects and capture them in their mouths, and their wing and mouth shapes help them to do that. On examinati o n of other c h a racters, s u c h as their toes, wing bones, and voice box structure, it becomes that swlfts and swall ows look alike only o.n the outside; Insi d e they a re. v ery diff e rent (Fig. 1-36 ) They have ind e p e ndentl y converged on the same overall body plan because they each have evo lv e d to do the same thing Because they did not start from the same point ( in other words, they had different ancestors), their exact "solutions are somewhat different: antelope have two toes at th e end of their long, running legs, whereas horses have only o ne; swall ows have long wings owing to a very long radius and u l n a (an elongated ant ebrac hium), whereas in swifts the long wings resul t fro m an elongated manus. Sometimes separating similarity owing to lifestyle from similar ity du e to co mmon descent i s r e l at i vely easy, but often it is diffi cult. Certain physical c haracter s are subject to very strong selection, espe cia ll y c haracters that help birds find food or escape e n emies. A bird with a stronger bill can open larger seeds; a bird with an efficient wing shape for it s flightstyl e uses less energy. All these d i fferences affect the Long Wings due to :::::---C Elongated Antebr,l chium Long Wings due to Elongated Manus Come II LaboratC>f11 of' Swallo w Co m p l ex Syrinx Anisodactvl Feet (Three T oes FonviJrd O n e Tae Backward)

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Chapter 1 lntrodu ctio n : The World of Birds .surviva l a nd r eprod u ctive s u ccess of the indivi dual bird, an d conse que ntly can b e r ather easily modi fied by natur a l se lecti on. As a result the bill a nd ove rall shape of birds w hi c h are often s t riking, may be of littl e help in discover i ng true phyloge n et i c relatio n ships. More useful 1 n d etermining relationships are c h a ra cters that var y among groups bu t that a r e n o t so easily c h a n ged by natural se lection-using these often minimizes the confusion r esu l ting from conve r gence In te rn al cha r ac t e r s ofte n h;:we been used because t h ey a r e con sidered (wheth e r r i g h tly or wrongly) to h e m ore evo luti ona rily conservatrve than external c h aracters. Ei
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1-42 DNA ''Unz ips" for Protein Synthesis 1\minoAcids One Base Patr I Protein If 1 fn reality, proteins are much longer ch
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Chapter 1-/ ntroduction: The World of Birds just by cha n ce, a mutation cropped up that changed the DNA code for making horns and a cow grew up hornless. It passed this mutation on to its offsp r ing, and those cattle with the new hornless gene were able to produce hornless young. With the understanding of DNA and the development of mo l ecular techniques, systematists (scientists who study how organisms are r elated to one another) began to look in different places for useful characters to construct classifications. They began to look at the chem ical makeup of birds, not just their outward (o r interna l ) appearance. Because DNA molecu les are very small, direct observation of these quences of bases is not possible. Researche r s usin g chemical methods to class i fy birds started by looking at things one step removed -not at the blueprints but at the building blocks of organisms, the pro teins. Certain proteins can be c hem ically isolated from an organism. Different types of animals make s l ightly different forms of the same protein (t h e forms all h ave the same function), and these differences can be detected. One important tool u sed to compare protein for m s i s electrophoresis. By watching how far each form of a protein migrates up a gel in an electric current (somewhatthe way ink bleeds ' up a strip of paper), different forms of the same protein ca n be separated (Fig. 1-3 8 ). Smaller or differently charged forms travel at different speeds than do others. This method was one of the first ways to look at chemical differences quite apart from (and thus vnbiased by ) external morphology. A l though proteins are the main building blocks of animals, they are still a step away from DNA. Ideally, what should be examined to determine relationships are not the produ cts of protein synthesis as translated from DNA, but the ac tual sequences of bases in the DNA molecules thems elves. DNA molecules, however, are too small for their structure to be "seen" directly, so various indirect methods are used to determine their base sequences. A number of different techn1ques have been de veloped to look at DNA, and each is useful for a different level of com-Protein mole cules Gel a. Protel'n Applied lo Slab of G Migmre Along Gel t\ccorcling ro Size. Handbook of Bird. BiolO[Jtj H3 figure J 38. Gel Elect rophoresis o f Proteins: protein mole c ules too small to see, even under a pow erful microscope, scientists must use indirect means to determine their form Gel electrophoresis separates large ecule;, such as prot ein molecules with dif(erentlengt/15, by rheir rare of move ment through a thin slab of gel in an e l ectric field. To create til e electric fie lei, e lectrode$ (on e negative Jnd one posi tive) are allaclwd to opposite ends of rhe gel, and the e le c tric c urrentistumed on. Rese.1rchers treat the protein molecules so that/he y carry a negative charge, and thus the pro t eins are attracted to the pos itive eledrode migrating slowly toward i t when the c urr e nt is on. Becatlse larger molecules are s/o
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144 Figur e 1-39. Nuclea r Ver s u s Mito chondrial DNA: DNA Is found in both the nucleus and milnchondria of animal cells. In the nudeus (command center), individual DNA molecules exist as ex tremely l o n e, thin coiled strands known as chromosomes Bird chromosomes wry >videl y In size ant/ their length s are not fully known, but they are on the order of tens of millions of base pairs (see Fig 1 -371 long ,ln the close-up vie .V, the chromosome is s hown as two identical DNA held together in the middle. nliS is the form DNA takes just /ie[ofe cell division (in which the two strands pull apart and one goes to each ne w cell) and is th e (I sua/ way chmmosonlf;s are illustrated. Mitoc hondria are small struc(Ures in the cytoplasm th e cellular material (oundovt side 1/)e nvc!eus Their sin gle chromosome is much shorter ( an avemgeof 16,000 base pairs lung Inver tebrates ) anrlln the form of a ril)g Animal Cell l( evinJ, McGowan pari son For example the information need ed to distinguish the more c l osely related two out of three c hi c k adee spec ies is different f r o m th e in formatio n needed to de t e r m in e which two out of three g r o ups, say, ducks h awks, and spa rrows are more close l y r e l ated. Here a brief overview of the tec h niques that are c urr entl y most important fo r c las s i fyi n g birds is p r esented. Thr o u gh a va r iety o f techniques, past resear che r s wer e ab l e t o actu a ll y read th e seque nce of bases in DNA, a process termed "se quen c ing. One rnajor problem was that a sing l e DNA molecule for a relativel y simp l e organism, suc h as a nema tode worm, contai n s millions of base pairs in its DNA. Sequencing takes t ime, and no o n e could possibly r ead the e ntire sequence a nd make sense of it. So, the firs t techniq ues u sed t o read DN1\ did not concentrate on th e DNA contained in t h e nucl e u s ( command center) of a ce l 11 where t h e plans forthewhol eorganism lie. In stead, t h ey took adva n tage o f the factthat l i ttle structures within the cytoplasm ( material outside t h e nu cleus) of each cell, the mitoch ondr i a (sfngu l a r : mitochondrion ) have their own DNA, which is much sma l l er and simp l e r tha n that found in the nucleus ( Fig. 1-39 ) The m i tocho ndri a are the "powerhouses of the cell," w h ere most of th e ene r gy generation takes place. They a r e proba bl y a n cient bacteria that somehow got incorporated into cells a t a very ear l y stage of evol uti on Part of the evidence supporti n g th e bacterial origin of mitoc h ond r ia is t hat their DNA i s very similar to that of b acteria: re l atively short and arranged i n a cir cle -unlike the l ong, co mplex strands of DNA, termed chromoso me s fo und in the nuclei of most cells. Researc her s were ab l e to iso l ate t h e mitochond ria l DNA (mONA) and seque nce specific r egions of it, DNA in Form of Chromosome fTI'ms ofMi/licm, s of Base Pairs Lon g Tn Birds ) Mitochondrial DNA "Ring" I 16.000 Base Pair, < Long. o n Average. in Vertehra.tesJ Cornell L..aboratont ofOmithol oacl

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Chapter 1-1 ntroduction: The World of Birds Again, problems were encountered. Mitochondria are not passed from both parents to t heir offsprin& but instead are transmitted i ntact from m other to offspring. Therefore, all your mitochondria came from your mother, and all of hers came from her mother, and so on back through time. Although useful for many studies, maternal-o nly inher itance presents some problems for understanding evolut ion. Nevertheless, examining mONA remain s an important tool in exploring evolution and the relationships of organisms, especially at the popu lation level (a population is a group of individuals of the same species that liv e in the same general area). Systematists recently have turned to seql.lencing nl.lclear DNA, but still are limited by how little of the whole DNA molecu le they can sequence. Most researchers, therefore, are restricting their work to specific regions of the DNA molecule, sequencing single genes for comparisons between organisms. This technlque creates the same problems that faced earlier systematists who used morphologica l traits to classify birds, namely that a single character is used to determine a relationship. To get around this problem, many systematists use anumber of known DNA sequences together with morph o l ogical characters to investigate the relationships among groups of birds Another technique using DNA for detecting relationships, especially at the higher levels of com parison is DNA-DNA hybridization. This techniql.le was used by Sibley and Ahlquist to const ruct the ir new phylogeny They collected and analyzed tissue samples from an astonishing one-sixth of the bird species of the world -the largest set of DNA comparisons made for any group studied to date. In the process of DNA-DNA hybridization the double-stranded molecules of purified DNA (which look roughly like incredibly small but very long, twisted zlppers) f r om two species are unzipped (Fig. 1-40). T hat is, the molecules are chemically broken apart down the middle, between the millions of base pair combinat ions Because a DNA molecule is more stable double-stranded (zipped) than single stranded (unzipped) the doubled-stranded molecules will tend to reform. If unzipped DNA from one species is put in contact with unzipped DNA from another species, the molecules w111 try to fuse wr t h one another. Of course some of the "words" in the genetic code of one species will be different from those in the other species (some of the zipper teeth will not fit together), so the base pairs of the hybrid DNA molecules will not be perfectly matched. The key is that the fit of those DNA strands that are most similar will be most stable, and that the stability can be measured. The more stable the hybrid DNA molecules, the more closely the two species are related. Binomial Nomenclature and Classification Early in the 18th century the time of great explorations to all parts of the globe, expeditions returned to Europe bearing new plants and animals by the score. Natura lists in different countries gave them different names; there was no uniformity, no standard followed by all naturalists in all countries. How long this chaotic situation might have Handbook of Bird

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1-46 Figure 1-40. DNA-DNA Hybridizati on: DNA-DNA hybridization is used to de termine the degree of similarity between two different samples of DNA. At the top of this schematic a short section of DNA irom two different species is illustrated; in the.1ctual process, however, the entire molecules would be used. The different shapes along the line down the middle of each represent the different nitrogenous bases. For example, the square might be ar;Jenine, and the square hole : thymine (see Fig. 1 3 1) ; and the triangu11u peg" mightl>e cytosine and !he tria n gvlar "hole, guani ne. First, the DNA samples are heated to break tile bonds between the base pairs disas.mclating (separating) each double-stranded molecule into two separate strands middle drawing) a process termed # me/ling. H Because DNA is more stable in thedouble-.>tranded form, single DNA strands in the same sample wTI/ bond together to form double str,lnds, unless kept apart by high temperawres. Therefore Nmelted samples from each spe des .1re combined, and held at a lower temperature, allowing douhle-stranded molecules to form. Aithough ma11yoithe single strands will bond with another stmnd from rhe same species, snme of the sttands will "hybridize,' bonding with the DNA of the o ther species (bot tom drawing ) Because hybrid douhle strands do nor have perfeclly matched base pairs, they are less Mable, and thus separate more readily when reheated. Furthermore the greater the difference between the base sequences of the two species' DNA the l ower the melting temperature or the mixture of reformed double-stranded DNA molecule5-giv lng researchers a quantitative measure of the degree of similarity between the DNA molec:t1les from the rwo species. Adaprecl from Prperot ;md L)inch / 1993 p 2J/. DNA Samples from Two Spe<:ies ar e Collected and Purified Species I DNA Strands Species} DNA Strands The DNA is Heated to Disassociate the Mo lecules into Individual Strands. The Samples are then Combined to Form Hybrir;/DNA Tl1e N y brid DNA is then Reheated and the Melting Tempera ture is Ana /yzed Mismilt c hed Areas are Weak and More Reildil) t Disassociate when Heated Hybrid DNA fron1 Both Species Comell Lnborator'1 of'Ornitltoloatt Kevirr j. McGowan

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Chapter 1-lntroduetion : The W orld of Birds continu ed is an y body's guess, had it n o t been for Swedis h natur a list Caro lus Linn aeus ( 1707 to 1778). A genius at organizat i on he set u p a syste m1 binomia l nomenclature for all p l a nts and a n i m a l s This method was so u seful that it soo n became the s t anda rd system and biologi s t s have use d i t eve r sin ce. Linnaeus designated eac h p lant or anima l by two L ati n names, t h e (i rst denoting the genus ( pI u ra I g en e r a ; a I ways capitalized ) a nd the second, the s pecie s (plura l a l so s p ecies ; n ever ca p rtalize d ) He chose L ati n because i t was the universal l a n g u age of schol a rs, a nd he used two names because there were not e n o u g h s i ng l e n ames in the l an guage for all t h e s pecies, Thus, a lthou g h the second word is o ffi cially c a l l ed t h e species' designation, both t h e gen u s and species must be writte n toget heno I n dicate a uni q u e organism because there m ay be more tha n o n e unique o r gan ism w ith the sam e "s p ecies desi g n a ti on ( for examp le, the Fly catc her, Empidonaxminimus, a n d the Bushtit, Psaltriparus minimus ) To allow e asy r ecognit ion of these two-word Latin ( o r scie ntifi c") names for species, t h ey are always und e rlin ed or pliiced in italics The indi sputable value of L i nnae u s system ca n be d e m onstra t ed toda y by exami n i n g all the commo n names for a ce r t a in l arge bird of p r ey that r anges widel y over mu c h of the world, The "offici a l Engl is h name is Osprey, whil e In so m e parts of both t h e Unite d States and ((lnada il is known a s the Fish Hawk. The Swedes ca ll it Fisk gjuse; the Ge rm ans Fischadler; the Dutc h V isar e n d ; th e South Africans, Visvalk; the Burmese Wunlet; and t h e Argentines, San gua l. But to a ll ornithologists, r egard less of the l ang uag e they speak, t h e bird i s Pandio n haliaetus. Thi s illus tr ates w hy guides to identifica tion an d other autho r i tative treatises g i ve the sci en tifi c names after th e common n ames-t o elimin ate a n y doubt in a nyon e's mind about the identities of the birds mentioned. Every scientif i c n ame m eans somet hin g (Sidebar 3: Latin and Gre ek Roo t s of Bi o l ogicallerms). The n ames a r e co ncoct e d fro m L a t i n o r Gree k roots, or at l east made t nt o the for m of Latin words. Although some names m ay have b een created to honor a person many of th e translated root s a r e descr i ptive and usually provide some informa t i on abou t the organis m For exa mple, the familiar American Crow is known as Corvu s brachyrhynchos. Corvus comes from the L a tin f o r croW ,11 and brachyrhynchos means short beak w hi c h a crow has compared to a rilve n Linnaeus used very few hig h er categories t o express the orga n i za tiona I affinities of genera. But as more organ isms were described a n d fitted into the classif i ca tion sc h e m e new categories had to be add e d to supp l eme n t and orga ni ze the U nnaean categor ie s of genus and species. Eac h type or form of an irna l or pi
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t.48 Kevin J. M cGo wan Sidebar 3: LATI N and GT\EEK 1\00TS of B IOLOGICAL TER,MS Marie Eckhardt Students new t o the field of bio logy may find the terminolog y daumfng. Man y biolog ical terms and names, h ow ever, are d erivP.d f r o m Latin o r Greek roots. Onc e you becom e familiar wi t h these roots you wil l find tha t b i o l ogical terms are mor e c ompre h ensible. You may alread y be acquainted wft h som e of these terms. Many are p resent in our everyday language as prefixes or suffixes embedded in familiar words. The latin a nd Greek roots presented here are each spelled in a form that is co mmonl y enco untered in bio l ogical words but these are not necessarily the o rig inal forms. Additiona l information may be found in laeger(1955) and Pough er al. ( 1996 ) Root Mean ing of Root Example and Definition a, ab a\vay from a, an witho ut lacking n ot ad to, toward, attac hed to a ero s the air a l a lu l a awing a l b white a ll allo other aqua water amp h i both double and r o male ante before an1h ro human arch beginning fir s t time audi to hear av a bird bi bi s tWO bi o related lo life b l ast bud s proul bra chi arm earn flesh cau d tail ceno new recent cord guts, a string c ho r i o skin membrane ab ductor muscles: muscles that draw bo nes away t r o m the ce nt er of the body a biotic: n o t living ; apteria: areas of bird skin that lac k feather tracts a dduc t or muscles: muscles that draw hones toward the center of the body aerod y namics: branch of science dealin g w ith the motion of air and objec t s in air a l u l a : feilther s attached to the first digit in a bird's w1ng albino : lacking colo r pigmentation a ll opreening: the preening of one b ird by another aqu a tic: living primarily in or on water amphi bian: a class of vertebrates that spend part o f their lives in water and part on the land po l y andry: mating system in w hi c h a s in g l e femal e m a tes w ith several males in a !.>reeding season antehrac h ium: the forearm of a bird-the part before the brachium ant hro pomol'phic: ascribing humiln qu a lities to non humans Ar c haeopteryx: the earliest k n own fossil bird audi tory: related to hearin g avian: relating to birds walking o n t..vo feet b i o logy: the study of life b last odisc: rlatlened sphere of cells that is t h e 'f irst stage of devel opment in the bird embryo brachial artery: main artery of the human arm and bird wing carn ivorous: meat-eating cau d a l verrebrae: bones of the t a il Cen o zo ic: t h e most rece nt geological era spinal co r d : cable or thi c k "string of nerves running the length of the vertebral co lumn c horion: membrane surroundin g the embryo yol k sac, amnion, and a l lantois in a bird egg Cornell l.Aboraton1 of Omltholo&tl

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Chapter ?-Introduction: The World of' Birds Root Meaning of Root chrom col or dde kil l ing circa about, approximate l y circum around cl oac a sewer cran skul l dac t y l ffnger, toe de remova I of off derm skin, covering di diplo IWo, double e, ex out of, from, without eco, o iko s house, home ect outside e nd with in, internal e pi upon, above extra beyond, outside f ru g fruit gallu s pou l tr y gastr belly stomac h gen origin geo earth g loss tongue gon seed g ul throat gyn female h emi hal f he p a l the liver h e t e ro different, other homo alike hydr h y dr o pertaining to water h y p e r above, excessl\le E xamp le and Definition c hr o matophore: a pigment-bearing cell pesticide: ' sensitive Handbook of Bird Biolo84 I

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1 Root h ypo inte r intra leuc, l e uk kin klepto mel a m e s o m eta mic r o milli mono morph n e phro neuro nidi nom e n not omni 00 ology oper c u l optic ornith O S ov, ovi paleo p a r para parou s path peri phe no Meaning of Root below insuffi c ient between w i thin I nside white movement to stei\1 b lack midd l e to c h ange small a thousa n d o ne, s i ngle s hap e kidne y n erve nest a nam e t h e back all p ertainin g to an egg study of a cover; lid eye bird bone p e rtainin g t o a n egg ancient besid e bear i ng, giving b i rth to disease a round visible Kevin J McGowan Example and Definition h y p othermia: subn o rmal t e mperat ur e of t h e body i nter spedl'ic: occ urr ing or existing between dif feren t s p ecies intracellul ar: occu r ring o r f u n ctio nin g w i thin a cel l l e uk ocyte: w h ite blood cell cranial kinesis: the abi l i t y of bird s L O raise the Upper beak whi l e sim ultil neously depressing the low er beak klepto parasitism: r o bbin g anothe r bi r d species of its p rey mel a n i n ; a dark br ow n or black pi gme nt mes o bronchus: mai n air tube running d own the midd l e of each bird lun g metabolis m : a ll the p h ysical and chemical processes of a n organ ism, including those by which food is co n verted to e nergy or hocly s tru c tures m i c rocHmate; the loca l climate o f a small s ite o r hilbita l millennium: a perlocl o f l ,000 years mono gamo us: havin g jus t o n e m a t e 1n a given per iod of tim e morph ology: the stucly of t h e form and of something n e phro n : the e x cretory unit o f the vertebrate kidney n eurotoxin: a poiso n tha t acts on t h e nervous system nidi co lous: reared in a nest nom e n clature: a syst e m of naming notochord: a fle xib le, rodl ike s upport running along the back of a ll c horclale e mbryos omni vorous: feeding on both a nim a l and veget<1ble materials oocyte: a n imma tur e egg cell ornith o l ogy: the study of birds o p er culum : a protective flar coveri ng the no s t r i l s of some birds s u c h as starlings, pigeons, and chickens optic lobes: the portion s of t h e b r a in tha t process infor m a ti o n o rnithologist: o n e w h u studies birds o ssicle: a small hon e o r bony s tructur e ovary: femal e r eprod u c t i ve nrg11n tha t produces eggs paleonto logy: the study of pas l geolog ical p e riods as known from fossils p ara site: a n org;Jnism that lives at t h e expense of a nother species, often in or upon it ovi par ous: prod u ci ng eggs tha i develop and hatc h o u tside the female's body path ogen: disease-causing agen t peri pheral v i s ion: the oute r part of the field of v iew pheno type: the visible properties of an organism Com ell Laboratortj of Omitholo[lt t

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ChQpter J -lntrodu ctioll: The World of Birds Root Meaning of Root phy l t ribe, race plasm formative substan ce p od foot po l y m a n y po s t after pr e before, in advance o( prim fir s t pr o befo re, favoring pier w ing, feather p yg the rump soma body sonus sound sub b e low, under, s mall e r supra above, over sym syn tog et her, with tax arrangement of tel e far off, distant l h er m heat tri three froph nourishment ultra beyond uni one, single ura, oura tai l or urine vas a vessel ventr the bell y verm worm viv live vo r to devour xer dry zoo a nima l zy g union coup l ing Exampl e and Defi nition p h y l um: one of the primary divisions of the anima l kin g dom cyto p lasm: formative substance in cell s 151 megapode: a groun d -dwelling bird that uses irs l a rge, strong feet to construct mound nests po l y gy ny: havin g mor e than o n e female mate ill one t im e po s t nuptial: occurr in g af t er breeding pre coc i a l : young bird that hatches i n an advanced state of matu r itycapable of much independent activ ity before (at an earlier age t han) altricia l young prim ary feathers: outermost f eather s of a bird's wing proven tricu lus: the glandular or tr u e stomach of blrds that i s sit u atP.d b efo r e the gluar d pt erosaurs: exti n c t fly ing reptiles pygostyle: the last bone in the tail oi a bird, formed hy the lus ion of several tail vertebrae somati c cells: the body cells, in co ntrast r o t h e sex ce lls (the eggs a .nd s perm ) sonagrarn: a n image prod uced by sound s ub ordinate: occupyi n g a lower rank class, o r position s upra co raco ideus: a principle flight muscle that is attac hed to the humerus a bo n e located above the coraco id sym patric: occu rrin g in the same a rea tax onomy: the classification of o rgani sms telescope: a tubu lar opti cal instrument for v i ewing distant ob jects th e rm omete r : an instrument that measures temperature Foramen triosseum: a hole formed by the junctio n o f three b o nes in the s houlder j oint of b ird s t roph ic level: level in the food chai n at wh i c h an o rganism seeks its nourishment ul t ra vio let: a portion of the light spectrum beyond the blue and vio l et wavele ngths uni form: consistent, having a singl e form manner, or degree u r opygial g l a n d: oil glan d at the base of the t ai l i n birds vas deferens: duct that car ries sperm i n verteb rates vent r a l : anat o mi calty, the l ower or abdo m inal side of the body v erm ivorous: worm eating viviparous: g i ving birt h to live young herbi vorous: plant -eating xeri c habitat a habitat with very little moisture zool ogy: the study of a n imals zyg ote: the cell formed by the union of the sper m and egg cells of anima l s of Bird Bloloa'l

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1-52 Kevin J. McGowan somewhat similar are gro up ed withr n t h e sam e ge nus. Similar gene r a are p l aced within a f amily simi l ar fam i l ies within an o rd e r simi l;u orde r s withi n a class, simila r classes within a phylum an d fina lly, similar phy la wi thin a kingdom (Fig. To help understan d the classificat i o n system, l ook again a t the crow. T h e species AmerTcan Crow, Corvus brachyrhynchos, lives over most ( b ut not all ) of North America from Bri t ish Columbia to Mexico and F l orida I t can be separated from other spedesof c rows and ravens by its calls, the size of its body parts, i ts s hape, and the shape of the back and throat feathers. A ll crow and raven species are placed in the genus Corvu s A lthough not all of the 50 species of crows and ravens found throughout the wor l d are entire l y black most would instantly be Classification of the CATEGORY America n Crow Other Examples of Category KINGDOM A n imalia PHYLUM Chordata (Ch or dates) C LASS Aves ( B i rds) ORDER Passeriforme s ( Pcrc:hin g Birds) FAMILY GENUS SPECIES All Other Kingdoms : Plantae, Fungi, Mon e r a (Bacte ria) Protista (Misc. Simpl e Organisms) Examp les of Other Animal Phyl a : Porifera (Sponges) Nema todn ( Roundworms), Arthropoda ( Arthrop()ds), Moll usca ( Mollusks) All O t her Chordate Classes: A gnatha (lawless Fis h), C hondri c hthye s (Cartilagenous Fis h), f i s desiynated b )' a unique twu-word scientific or "Latin" name, according to the system develupecl by Carolus Linnaeu s in the 18th century. The iirst word of the name is the genus, and the second the species. Both are underlined or italicized and the genus (but never the species) is capitalized. For example the .scientific name oil he bird species common/}' c alled /he American Crow Is Corvus brachyrhynchos. There are other species w i thin the genus Corvus, and e.Kh has a different word ior the designalioTJ. As shown for the AmeriGJn Crmv, related genera are placed within the same family related families within the same order related orders within the same class, and so 011. No t e that (or the kingdoms and c hordate classes, all possibilities are shown but for the other categories, onl y a selection oi e l(ilmpll'S is given People use various mnemonics lo remember the levels in the classification scheme, but one effective one is; !;a me Qver Eor !J.ood Spaghetti," in whi c h the iil"stletter of each wo rd gives the 1/rstletter of each category, in the proper sequence. C o m ell Labor atofit of Omitho lofJ'I

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Chapter 1 1 ntrodudion: The World of Birds as similar to the American Crow: they are large, mostly black, omnivorous, intelligent birds. Crows and ravens, together with jays and magpies, make up the family Corvidae. Most corvids are large, omnivorou s birds with feathers covering the nostrils on their stout beaks. Corvidae Is just one family in the order Passeriformes, a group containing all of the familiar songbirds. Passeriformes are rec ognized by their overal l perching physique (three toes forward, with a well-developed hallu/<) and especially by the uniquely complex structureoftheirsyrinx (voice box ). The31 orders of living birds make up the class Aves, or birds Among l iving organisms, birds are instantly recogn i zable by theirfeathers. Together with the various other animals ( fishes, mammals reptiles amphibians and the strange lancelets and tunicates ) whose embryos share certain characteristics such as a noto c hord ( a rod-like support along the back ) and gill slits, birds make up the phylum Cho r data within the kingdom Animalia linnaeus' basic system of classification is still in use today albeit with many changes in names and positions of the organisms. It is, of course his system that is important, not necessarily the classifications he made. For example, he lumped whales in with fish even though two thousand years earlier Aristotle already had rea l ized that they were different. Linnaeus classification of birds was based heavily on the stn.1cture ofbi lis and feet and consequently grouped together such odd bed mates as parrots, woodpeckers crows and orioles The Species The species is the basic unit of classification of I iving organ isms Species serve as the basis for describing and analyzing biologica l diversity. By the prevailing Biological Species Co n cept ( BSCl, a species is a group of potentially interbFeedi ng individuals tliatshare distinctive characteristics and are unlikely to breed with individuals o( other spe cies. Although most species are recognizabl e by obvious str u ctural and behavioral peculiarittes-how else could they be identified as diffe rent species in the field? the ultimate criterion for defining them is whether they are reproductively separate. To retain its distinctive ness and thus its 'species status, a group of organisms must not breed with other species; that is there should be no ge ne flow ( movement of genetic material as between generations) between species. There are exceptions to this general cri t erion for defining species however. Hybrids between different but closely related species do occur in na ture Notable examples include the B l ue-winged and Golden winged warblers and the Mallard and Black Duck. In such cases, ornithologists have concluded that the frequency of hybridization fS in sufficient to c onsider calling the birds the same species. When just one region is cons id ered, species seem easy to identify, but when the entire range of organisms across the globe is considered, the boundaries between species become murky. Life is complex, and organisms do not always fall into the neat little categories that people desire. The main criterion for the BSC, that individuals of two different species will not interbreed, is often useless in practice. Similar Handbook of Bird BioloaLJ 1 I

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I J .54 Figure 1-42 S ong Sparrow Cline: Sons Sparrovs found on the P,>c ilic coast of North America show a gradual ch.1nge (termc'Ci a clineJ in bod y 5ize, plumage coloration and song t;:h..uacteristics, when considered from north to south. The dark Aleutian subspecies appears dttln1iiltir;ally dilferent from the small pale 5uhspecies of the Sowflwe s tern desert with the Pacific NorthWe$t and California s u bspecies showing intermetfil!te c hM acteristics. Reprinted from Manual of Or11ilhology, by Noble $. Pmctor and Patrick}. Lynch, with permission ol t h e publisher. Copydglll 7 993, Y'illt> Unf vecyi(y Press. KevinJ. M cGowan b i rds may l ive in qui te separate l oca l i ties and thu s have no chance of interb r eeding (for examp l e, American Crows a n d the s imilar look i n g Carrio n Crows of Eurasia ) Are t hey different spedes? W h at woul d happen if they came into contact? H ow cou l d a nyon e begin to guess? A n d does i t really matter i f a few indlvtdu a l s in terb r eed? Woul d t hat mean that the two for ms s h are most of t heir genes o r j ust that th ey do notrecognizeeach o th e r as differe n t forms? Beca use of 9issatisfaction with probl e m s s u c h as these a n umber of people dislike the BSC, a n d have propose d oth er definrtio n s of species. One spec ies concept that has gai11.ed much suppo r t is the Phy logenetic Species Concept (PSC) This fdea is mor e concerned with A n Example of a Clin e : Padfi c Coast Subs pecies o f th e S on g S p arro w (Me l o s p iza m e lod i a ) Cornell L.aboratorlj of Ornitho loat l n

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d!apter1-lntrodetion: The World of Birds separate evolutionary histories than interbreeding individuals. If two forms became d i fferent (eithe r morphologically o r chemic::a lly) because they diverged genetically al some point in their evolutionary histor y the PSC conside r s them separate species. The PSC is not based on hybrid ization or guesses about whet h er species will I nt erbreed, but is con cerned onl y with discrete, recognizably different forms with separate evol utionary histories. Under this concept, the number of bird species recognized in the world wou ld be approximately doub l e the number recognized by the BSC. For examp le, consider two forms of the North ern Flicker-the Red-shafted and Yellow-shafted f l ickers-named for the bright l y colored feather s haft s of the wing and tail. In addition to shaft color, a number of differences in the color patterns of the p lumage distingu ish the two groups The red-shafted form is found throughout western North America and the yell'ow-shafted form, throughout east ern North Amer ica, but they interb reed within a narrow n orth-south zon e through the Great Plains, extend in g northwest to southern Alaska. The BSC would proclaim these forms a s1ngle species (their current official designation ) because of the extensive interbreeding. The PSC, would declare them separ ate species, consi der ing the distinct plumage diffe rences to indicat e separate lines of evolution. Like the human species, all bird species s how ind i vidual varia tion. If a species r a nges widely over geographical areas that encompass shifts in t!nv ir o n menta I conditions, such as from warm to cold or humid to arid climates, it is likely to show a gradual change (called a cline ) in certai n characters from one population to the next. The var iat i ons between populations may be in o n eormoreofa number of characte r s including col oratio n body size, b ill size song, or numb er of eggs laid ; these variations a r e roughly correlated wlth changes In geograp hical areas (Fig 1-42). Somet imes the changes in characters a r e abrupt, especi a ll y if physical barriers such as a l a rge body of water, a mountain range, or a desert separate the populations. Whether gradual or abrupt, popu l ations in certai n geographi ca l a reas may be sufficient l y distinct to warrant the designation subspec ie s sometimes call e d race (Fig. 1-43). When a subspecies is iormally described in the scientific literat ure, it receives a thir d name after the binomial. For examp le, the common American C row in New York i s Corvu s brachyrhynchos brachyrhyn chos, whereas the smaller form common in California is known as Corvus brachyrhynchos hesperis. A subspecies i s defined as a popu l ation of a species that has some uniqu e c haracters and some that a r e shared with other populations and which can interbreed wlth other populations when they mcel. Subspecies, then a r e separated onl y geographically, not reproduct ively. In practice, reproductive isolation i s difficult to detect, so under the PSC m a n y geographicall y isolated forms would be considered full species. The Formation of Species As discussed above, widesp read species are composed of popu lations that, through geographi cal sep amt i on, may become suff i c i ently distinct to warrant the i r designation as s ubspecies. I f the isolat i n g fac-Hand hook of' Bird Biolo,qtf 1 55 I

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I 1.56 Figure 1-43. Races of the Dark-eyed Junco: Familiar tor its pale beak and white outer tail leathers, flashed con spicuousl y in flight or during displays the Dark-eyed Junco has a number of different subspecies ot races. Males of three of the rac e s .1re pictured here. All breed mainly in c oniferous or mi, xed coniferous!deciduou5 forests. The Slatecolore d race is widespread in North America . but much more com mon in the e.1.searchers consider the Pink sided r,JCe a pale version of the Otegon race. Not shown ;ue Cr,,y-heaclecl and White-winged races. Where their ranges overlap lf1e Dark-eyed funco races interbreed producing o((<;pring with inlermecliate co/oriJ/ion Hybrids between the S/,,te-colored and Oregon races are particul,lrfy common especially in the Great Plaim. The f,1c1 that the Dark eyec/Junco races are in geneml separated geographic,11/y hut n ot reproductively is evidence that th e different forms on c e each con sider('(/ scpa"rte species are actually races oi a single spe cies. Slate-colored rac:e photo by Marie Read; Pink sided and Oregon race photos of Tecl Willcox/C/.0 KevinJ. McGowan Pink sided Oregon Cornell Laboraton1 ofOmitholotjiJ

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Chapter 1 -/ntroduction: The Worl d of'Birds t ors cont in ue operati ng, t h e subspecies may eventually develop sti l l str o n ger dist i nctions unti l thei r populat i o ns, u n ab l e to interb r eed, become spec ies ( F i g 1-44). Evol utio n of th i s sor t (ter m ed divergent evo lut io n beca use one group ''diverges" i n to two or more) resu lts i n the generation of new species a p r ocess known as s peciation. T h e geograp h ical separation that leads to spec i ation is frequen tl y caused a b Hanel book of' Bird Bioloatt 1 57 F i gure 1-44. Speciation throu g h Geo graphic I s o lation : When populations of a species become geographicall y iso lated from one another, s p e cia tion (the iortnation of new species ) may o ce-ut. A$ an example consider the population of white birds shown In ( a). It become> divided into two populations that do not interhreerl becaus e they ,1re geographi cally isolated b y t h e forma tion of a large river ( b ) Over lime each population fs different ecological iaCtOt5, whic h cause natur.11 selection to favor different in each-represented b y tl1e bla c k ve;sus white plumage In (c)1 and t he two population s diverg e ' in a process known ils divergent e v olution Such ecologi cal factors might include slightl y different food supplies predawrs, hJbitats nesting materials and c ompetitors. I f the two populations b e come so different that /hey can no longer Interbreed the y are considered separ ,1te species In ( d ) the two popu lations have rcesrablished contact with one another ( due to ronge expansion or remrWRI of the geogrophi c barri e rt, y et they lullil? r(;!tained their separate iden tlties-demonslraling that they are prob a/;Jiy not interbreeding and are indeed separate spedes. Adapted from Mader (1988 p. 522 1

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1 KEY Dusky An tbird 0 lndividuiil Record D Range Blac kish Anlbird Individual Record [0 Range Figure 1-45. The Role of Geographic Isolation in A11lbird Speciation: In the rain forests of South America, the VilSt Amazon l. Morton, Robert S. Ridgely, and Francine G. Buckley. Ornit!Jologicill Monographs No. 36, published by the American Ornithologists Union 1985. Reprinted b)' permission oftheAmerican Ornithologists' Union. Kevin J. McGowan by physica l barriers The formation of new mountain ranges the for mation of new large bodies of water, or changes in climate and the consequent changes in the d i stribution of speci fi c habitats can be respons ibl e for separation of bird popul ations and the formation of new species ( Fig. 1 4 5). Because populations exist at every conceivable intermediate stage between recently isolated populations a n d compl e t ely separate species, decisions on how to draw the artif i cia l ''spec i es/subspecies" line are usually controvers i aL Often, there simp l y is not e n ough infor mation to determine exac tl y where on this continuum the forms lie. In some cases, future work may shed light on how diffe rent the fo rm s are a nd how much gene f low exists. In othe r cases, the distinctions a r e more a matter of perspective: diffe rent people would categorize the populations differently. I n some cases "superspecies"-gr oups of close l y re l ated species-can be described, such as the Great B lu e Heron of North America, the Gray Heron of the Old World, and the White-necked H e ron of South America. Differentiating between Stk perspec ies and groups of s ubspecies a l ways wi II be content i ous. New species a lso frequently evolve when a small popu l ation of birds colonizes a distant island, and further gene flow with the parent popul ation is mini ma l or nonex ist ent. Over time the founding popu l ation evo lves to be b ette r adapted to the l ocal e n vi r onment: some traits d isappe

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Chapter 1-1 ntroduction: The World of' Birds isolated islands is colonized, natural selection may proceed differently on the different islands eventually producing a n array of new spe cies that all evolved from the same founding species (Fig. 1-46) The formation from a common ancestor, of a variety of different species adapted to different niches and behaviors, usually showing different morphologies (sometimes drastically different) is known as adaptive radiation (or simp l y "radiation"), Although adap t ive radiation is not restricted to islands very iso lated island chains present some of the most striking examp les. The Galapagos, a clus t er of islands 600 miles ( 965 km ) off the west coast of'Bird BioloB'f 1-59 Figure 1-46. Adaptive R ad iation on Islands: New frequently evolve when a small population of birds col onizes a distanLisland and gene flw with the parent population becomes minimal or nonexistent When a group of islands is colonizeci natural selection may proceed differently on the different islands, eventually producing an array of new species in a process termed adap live radiation. a. In this hypothetical example, species A from the mainland colonizes the closest island. b Over time different selection pressures (f a c tors that favor one trait over another) on the island cause thefoundin!J population to evolve enough differences to become a new spedes Indicated as B. Species B spreads to the next closest island. c. Over more time the population of 8 on the second island adapts to its new environment, evQiviniJ into new species c; which spreads to the nex t island as well as to the first, where it is unable to interbreed with species 8 and remains as a separate species. d. Eventually, spe cies Con the third island evolves to be .;1 new spe cies, 0 which spreads to the last two islands and back to the second island, where it remains separate from C. e. Finally, the populations of species D on the last two Islands each adapt to the co nditions on their own island forming two new species, and F. Adapted from Campbell ( 1990, p. 468 ) I

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I 10 Figure 1-47. Adaptive Radiation in Darwin's Finches : me Galapagos I slands are home tO ,1 c r oup of finc hes known a$ Galapagos Fin c hes# o r Darwin's Finches." Now p l aced within the family Emberizid.1e the 14 species a r e a classic example of adap tive radia t ion, as the y a r e all thought to have evo l ved from a com mon ancestor that r eachecl th e islands from Sovth America. Although they a r e simi la r In appearance-gray. brown, black, or greenish, sparrow-sized birds with short wings a n d tails-the s hape and r e lativ e size of th eir beaks differ irom species to species. Beak s hape is not an if)fallible identifica tTon aid, tho u g h as it varies widel y among indivi dual s wit hin some spedes, especially among populations of the same species o n different islands. BiJsed o n feeding habits, th e fall roughl y i nto three gro up s the groun cf. fin c hes, the wa rbler-like finches, and th e tree-finches, but tl1ere is consider able diver sity within the groups. See t ext for details From Pough, F. H.,). 8. Heiserr and N Mcfarland V e rtebrate L ife, 4th Edition. Copyrig ht 1 996 PrenticeHall. Reprodu ce d by pefmissfo n of PrenticeH all, Inc. Darwin's Finches K evin J M cGowan of E cuador, a r e a ve ritabl e laboratory of recent speciation. Never con n ected to one anoth e r or to Sout h America t'he s m a ll volcanic i sla nd s were atfirst without life. Gradually, th ey acq ui red habitats that could support the animals that reached them accidentall y from overseas. The separate forms of mockingbirds and tortoises found on eac h i sla nd provided a n importan t sti mulus t o C h ar les Darwin as h e developed his theory of evolution. Th e Galapagos a l so are hos t to an ar r ay of finches. These "Gal a pagos finches'' (order Passeriformes fam il y Emb erizidae) a r e a class i c example of divergent form s evolved from a common a n cestor. These birds are com m on l y known as Darwin's Finches a lthou g h Darwin did not noti ce their similar ities until theeminentorni thologist)ohn Gould pointed them out whil e viewin g Darwin s collecte d specimens. The 1 4 species found toda y probabl y radiated from a s i ngle a n cestra l fin c h species that ar ri ve d o n the Galapagos relative l y rec ently from Sout h America Limited dispersal isol a tion and adaptation to different types ol fo ods foun d on the i s lands eve ntu a ll y produ ced an a rr ay of s pe c ies with notably differ ent b eak types-altho u g h m ost a re st ill clearly variations o n the typ i cal seed-eat in g fin c h beak (fig. 1-47). Based on feed in g habits the fin c hes fall rou g hl y into thr ee g roups : Ground R n c hes ,, ,,,,,be.Jked Cmund-Finc h ' ----------.,., Seed Eating Ground-Rnch Warbler-lik e Ftnches ., ., --------ComeLilaboratorLt ofOmil'holoB'/

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Chapter 1-lntrodudion: The World of' Birds Ground-Finches: The Smal l Medium, and Large ground-finches use their strong, conical beaks to c r ack and eat seeds-their names re flecting the relative sizes oftherr beaks. Smaller species are restricted to eating smaller and softer seeds. The Sharp-beaked Ground-Finch has a longer more pointed beak, which it uses to probe flowers for nectar and leafl itter for insects and seeds. On some islands, birds of this species )lave even longer beaks, which they use to draw and drink the blood of large seabirds (see Fig. 6-30m) and to bi eak open seabird eggs and drink the conten t s TI1e Small, Medium, a n d Sharp beaked ground-finches also remove ticks from 1guanas and tortoises. The Common Cactus-rinch has a longer, thinner beak that it uses i n a variety of ways, most notably to extract nectar, pollen, and pul p from p r ickly pear cacti. T h e Large Cactus-Finch has a large, heavy beak that allows it to feed on larger seeds and insects than most other ground-finches. Warbler-like Finc hes: These two species have distinctive l y thin pointed warb ler-l ike beaks used for picking insects and spiders from flow eFs, leaves, and twigs, as well as for probing f l owers for nect-ar. The Cocos Island Finch is found only on Cocos Island, 390 miles (630 k m ) northeast of the Galapagos, w here being the on l y Darwi n's Finch, its foraging methods and diet have diversified tremendously. But interestingly instead of individual birds each using a variety of foraging techniques, d ifferent i ndividua l s wit h in t h e population have adopted dfffe r ent specific foraging methods. Tree-Finches: These bi rds spend significantly more time foraging in trees than do t h e ground-finches. The Vegetarian F inch has a s hort b r oad beak for crush ing and eatin g f ruits, leaves, and buds. The Small Med ium, and Large treef inches have conical somewhat par rotl ike beaks, whic h a r e oble to apply force at the tip a n d are used primarily to probe i nto decaying wood to extract insects. The Woodpecker Finch has a lo ng, stout tanager-like beak for prying large insects from bark and soft wood. The Ma n grove F inch, found i n dense mangrove swamps, has a similar but smaller, beak, used to capture insects and spiders. Woodpecker and Mangrove finches are famous for t h eir abili t y to use tools"-using cactus spines or twigs to pry insec t larvae and pupae from holes in dead branches (see Fig. 6-1 Oa). Even mor e spectacular, however are the Hawaii a n honeycreepers. The Hawai ian Islands, the most isolated group of islands in the world, once was hom e to an extensive bi r d fauna, now mostly extinct. From a gol dfinch-l ike ancestor arose several dozen species of small birds that show a remarkab l e array of bill sizes and shapes, all of wh ich evolved lo explo i t different niches on d i fferent i s lands (Fig. 1-48). Orders and F amilies of World Birds The living species of birds in the wor l d total about 9,600. Al l are named in accordance with the binomial system established by Handbook of Bird Biolo911 1

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1 Kevin J. McGowan and now cont rolled by the In ternationa l Commission of Zoological Nomenclature. Throu g h its code, th e Commission s t ipul ates how the names s hall be written, makes decisions on accep ting or rejecting names p roposed, and sometimes authorizes changin g or otherwise altering names already in use Appendix A lists the 3 1 o rders a nd all families o f living birds. Fig ur e 1--49 depicts t h e 3 1 orde r s in their primary habitats. j. Ula-ai-hawane(F..-.1 h. Hawaii Amakihi f. Kana Grosbeak (Ex.) _.,. e. Laysan Finch d. Ou Ex.) a. M aui Parrotbill Figure 1-48. Adaptive Radiation of Haw aiian Honeycreepel'!l: Illu strated her e are 14 of the 32 known species of /-lawai ian J-loneycreepers, a subfamily ( Drepanidi n ae witiJfn the family Frlngillidae l of s mall ofien co lorful birds with a bewildering variety o(beak shapes. Extinct species are noted with (EK.) after: the name. The ancestral honeycreepers were probably a tlock of cardu e /in e finches f r o m North America that smwed otJt.ovet the Pactfic Ocean and l anded on one of the Hawaiian Islands. TI1ey subsequentl y spread to the other islands, radiating into numerou5 species 1ith a dramatic diversity o{beak shapes and feediniJ habits Three members of the same genus (b, c and gJ 11/ustr,Jte the co rrelation between beak s hape and s pecifi c (unction The Lesser Akialoa (g) had a long slender, d ecurved beak for picking Insects from bark creVices as the bird hopped a l ong tre e limbs. The Nukupuu (c) ha!i a l o ng, s lender, s trongl y de curve d upper beak and a shorter, thicker lower beak; the l ower beak is used alo n e to chip and pry away loose bark as the bird se<1rches for insects on tree trunks. In the bizarre beak of the Akiapol.1au (b), the lower beak i s s trai g ht and stout, whereas the upper b eak / 5 slet1det, sickle--shaped, and n ear l y tWice as long. Holding its beak open t o k eep the upp e r beak out of the i Akohekohe m. Black Mamo (Ex, J way, the Akiapolaau chisels woodpecker-like into soft wood with the lower beak, then uses t11e long upper beak as a probe to reach insects. The beaks of some J-lawaiia n Honeycreepers are short Jnd stout. The thi c k powerful beak of the Kona Grosbeak (f) was used for cracking the small extremely hard fruits nf naio trees: and the thick par rot-like beak of the Maui Parrotbi/1 (a) is used to search for insect l a rvae and pupae by ripping i nto de<.
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Chapter 1-/ntroduetion: The World of Birds a Casuariiformes fntu 5truthtoniformes Ostrich Dinornithiformes 1-63 1in<1miformes 1in;m1ous Figure 1-49. Living Ordel'$ of World Birds: The world:< .31 orders of living !Jirds are .shown here in their primar y habitatswater, share, open ground, trees, or .1ir. n1is schematic only a pproximates the real world however, bt'<.atJse some groups a ctu a ll) co n(ain members in several different haiJitars, and because s ubtle variations among di(ferentl) pes of each major habitat are not s hown. The evolutionary r e lati o nship s i1t110ng the difle r e111orders are not well est.l/.Jiished a nd r emain highl y co ntroversial among ornithologists. Note that the bird sii/Jottetles are not dr llwn to scale. Handbook of Bird BioloB!f I

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i I Kevirt J. McGowan Orders and Families of Nort h American B irds App e ndi x B lists the l ivi n g orde r s and families of birds that occur in North America north of Mexico including H awaii. How Namin[j and C lassification Can H elp You Now that you have read the information on the naming and clas sification of birds peruse the l atest e dition of your field g u ide. In most guides the names and sequence of taxa a r e roughl y i n accordance with the lists in Appendices A a nd B. In your g uide, b e sure to note the fol l owi n g: (1) The s equenc e of o r der s and families. Try to learn as much of the sequ encing as yo u can. Besides h e lping you to crac k t h e book quickly a.t the rig h t place for a p artic ul ar group of birds, the sequence will g ive yo u recent scie ntific thinkin g on evol utio n ary relationship s a m o n g the groups (2) The sequ e n ce of s p ec ies wit hin a family. Although purely co n jectural, the sequence i s an attempt to put r e l ated species close toget h e r (3) The scientific n a mes of s pe cies i n a l a rge f amily o r s u b f amily, s u c h as t h e wood -wa rbler s P a rulidae. The words, whe n translated may b e helpful by describing the bird's appearance, behavior, r a nge, or habitat. They also maybe usef u l to yo u by exp ressin g r elatio n ships For example, t h e Black-and-white Warbl er i s so differ e n t fro m a l l the other warble r s that it warrants its own genus, Mniotilta; the T en nessee, Orang e-c ro w n e d Nashville, Virg inia's, Colima, and Lucy's warblers a r e so much more like one anothe r than like the rest of the wa.rblers that they s one genus, Vermivora (Fig. 1-50 ). Know ing this, you can better und erstand w h y these birds are so s imil ar in color patterns in the way t h ey nest, a nd in man y o f their songs and ca l ls. Th e Use o f C ommon Names U nlik e so many groups of organ i sms-plants, worms, insects, and soon-all b ird species have commo n names in Engl ish. Unfortunately not everyone agrees o n just w hi ch com m on names shoul d be" offici a I ," sorefere ncetothes c ientific names i s st i ll important. I n North Ame r ica, the common nam e s are so well established and familiar tha nks t o consiste nt following of the AOU Check-list; that both p rofessronals and amateu r s speak of species by thei r co mmon names, confide nt that everyone w fll know which species they a r e referr in g to I n t hi s course, ther efo re, b irds a r e r efe rr ed to by their com mon names. The common names given in the42"'1 Supplemen t to theAOU Check-li st(AOU 2000 ) are used for all species covered by that I ist. All species not covered by t h e AOU Checkl ist are referred to by the Eng li s h names p r oVIded by James Clements in his Birds of the World: A Checklist(2000). A I i stof the scientific names of all species me n tioned Come II L.aboraton1 of' Omitholog!J

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Tennessee Warbler in the 1-fandbook 01 Bird Biology, alphabetica l by common name is locate d after the referen ces, For dny species that occurs both in North America and in other countries where it has a different common n ame, the North Ameri can name is used. For example, Common Loon is used when speaking of the same species in Europe, where the English name i s Great Northern Diver. So that you will r ecognize when the common name of a p articular species is m enti"oned, itiscapitalized-forcxample, Yellow Warbler." Therefore, a Yellow Warbl er is a speci fie species, Dendroica petechia, and a yellow warbler is any warbl er thatis yellow. Throughout the Handbook of Bird Biology the following terms are used t o cove r part i cu lar groups of birds: R atites: A ll birds lacking a kee l on the sternum. Includes the flightless Ostr i c h rheas Emu, cassowar ies, and kiwis, as well as the tinamous which are full y capable of flight. Waterfowl: Duc ks, geese, and swans. Thus refers o nly to the family Anatidae. Water Birds o r Aqua tic Birds: All species with webbed ieetthat common l y swim, including the Anatidae; also, a ll deep-water wader s belonging t o the order C i coniiformes, such as herons and s torks. Seabir d s or Marine Birds: All species directly assoc i a ted with the open seas and consistent l y d e pendent on the seas for food. Shorebirds: Oystercatchers, plovers, snipes, sandp i pers curl ews, phalaropes, and sheathb i lis. Ornithologists in Brftain and the British Commonwealth, except Canada, speak of shorebi r ds as "waders. Har1dbook of Bird BiolOfjLI 1 F i gure I ...SO. Vermivora and Mniotilta WoodWarbl ers: B y nolinf!, the scien lific names of bird species ,111d which ones are p/,Jced in the s.Jme you may gain useful infnrmation oo tire ,rmong similar species. for example, among th e numerous species ,,r New Worltl wuud wariJ i crs liamily Parulidae/ the Black-and-white Warbler is distinct eno u gh 10 its own ge nus, Mniotilla whereas the Tennessee, Orange-crowned Nashville VifRinia's Colima, and Lucy's warblers dre more simildr to one ono t her to mher WJriJ/ers, and thus are plaum in the same ge11us, VermivorJ The Vermivora hnve slender. finely pointed bills tor picking insecL< irom leaves ,md hranches ; muted colors-usually olive green brown gray white ,mr/lor yellow; and songs fh,JI inrl11de trilled notes. The BI,Kk-and-white Warbler i > most dislim :tivc io tis foraging be havior: I t creeps /Ike .1 nutlwch along tree trunk s and large branrhes probing mto IJ,lfk ror insects and spiders with its slig ht/ ) decurved bill. Irs pldLemem in a separate genus is based primaril) nn anatom ical adaptations fnr tim style : lr has a much long e r hallu .,, shorte r tar5us, 181ger feet and S1run,:er t/1<111 other warMers Its genus name Mniotilta "moss-plucking ) also reilects this habit i111d its species designation, varia t"varieg.1tet"f # J reiers to its bold. striped plumage Tile 8/Jck-and-white Warbler also com monty lor,1ges among foliage gleaning insects like other wood warblers Photos ofTennC'ssee ilnrlB/ack-and-whitc war Mers courtesy nf Bill Oyer/CLO. Phow oi Orange-crowned warbler cotlf/esy of Donald W.1lti'JCLO

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1-66 Kevin J McGowan Land Birds or T errestrial Birds: All species not i ncluded in the aquatic groups above Gallinaceous Birds: Grouse quails turkeys pheasants, and al l o t her Gal l iformes; includes domestic chickens. Rapto rs: A ll diurnal and nocturnal birds of prey, name l y Falconiformes and Strlgfformes . Perching Birds, Passerine Birds, or Passerines: All species of Passeri formes. Songbirds : All passerines in the suborder Passeri. These birds have part i cu l arly complex voice boxes Occasionally for lack of a sui tably inclusive name for a group of birds the ordinal or familial name will be shortened; for example, "charadr1 i form birds" for t he order of shorebirds, gulls and auks; "alcids for the family of auks, dovekies, gui ll emots, mu rres, and puffins. If the names are unfamiliarto you, refer to the list of orders and families in Appendices A and B. Evolution of Birds and Avian Fliaht Did birds evolve 230 m ill ion years ago from sma ll arboreal reptiles called t h ecodonts or 1 SO million years ago from terrestrial theropod dinosaurs? Did feathers, which probably first evolved as i nsulation, then en l arge to promote gliding from trees, l eaping on the ground, or insect-catching? And what were t h e few birds l ike that survived the massi ve extinct i on s al the end oi the Cretaceous period-to become the wellspri n g of a ll modern birds?Theanswers to all of t hese questions remain elusive but the debates rage on. These comple1< and controversial topics are beyond the scope of this course b u t we h ave included an i n-depth d i scussion of them in an optional section located at t h e beginning of Part 2. This is an exciting area of resea rch because so many fossil birds continue to be discovered-as you may hear through the news media. These new findings compel researchers Loa I ter their theories, so out view of the relationship between birds and reptiles is continually evolving. Bird Distribution A l though bTrds are found nearly everywhere on earth their distr i bution is quite unev e n. Some habitats, such as tropica l rain forests, have n umerous species, w hereas others such as desert-s and alpine zones have few. Even among simi l ar habita t s the d i stribution is un even the rain fores t s of the Amazon Basi n i n South America host many morespeci!i'S per square mile than t hose of the Congo Basin i n Africa for example. Furt h ermore spec i es' ranges vary tremendous l y in s ize: some species such as the Northern Harrier and Tun dra Swan are found throughout the north ern portions of North America, Europe, CornelL Laboratort.t of' Orn!tholoEJtf

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Chapter 1I ntrocludion: The World of Birds and Asia, but m ost species have limited d i stributions. A few, such as the Kirtland's Warbler and Guadalcana l Honeyea .te1; are restricted to very small areas. Simi l ar ly, some bird families. s u c h as thE> swallows (Hiru ndinidae) and larks (Aiaudidae), h ave on most continents, whereas others are found on just one or two. Th e ea rth has not always looked as it does today, and appreciating w hy birds are distributed in these ways requires an und ers tanding of histo rical changes in dimate and the movem ents of the continents, as well as past spec i ation dispersa l and extinction patterns in differ ent lineages of birds. For a c hartoi the major geo l ogica l tfme periods. and a summa r y ofthe changes in (he global climate, the arrangement of the con tinents and the diversity of living things. see Appendix C: G e ologica l lime Sca l e. Two hundred for t y five million yea r s ago, a single land mass known as Pangea formed. It then broke apart into two large Laurasia. in the north. and Gondwanaland, in the south. These tually fragmented into separate cont inents ( fig. 1-5 1 ). Attached t o great p l ates that float on the molten rock of the earth's mantle the continents slowly drifted i nto d i fferent arra ngements-a process that continues to this day. Overtime, contine ntal collisions volcanic activity have created mountains, and erosion has lowered thern; huge basins have filled with water. and o th e r s have drained; and the output of energy f rom the sun has varied caus in g dramatic changes in the global climate. The early diversif i cat ion of birds took place on a very different earth ; n either the arrangement of the continents nor the distribution of climates resembled those of today. During the time that modern or ders of birds were evo lvin g, in the early Tertiary about 50 to 60 million years ago. Gondwanaland al r eady was breaking apart: South America had separated from Africa and India had split from Antarctica and was moving north to collide with Asia. North Amerka, Europe. and Asia remained joined as Laura sia, h owever. During much of the Tertiary period the world's climates were warm from pole t o pole, at1d birds moved throu gh the tropical-sub tropica l or warm temperate forests that covered Eurasia and North America. At first movement was easy across a broad North Atl a nti c land bridge. After the separation of North America from Europe dur ing the Eocene, however. the Bering land bridge between Siberia and Alaska became the main corridor for faunal exch ange between Eurasia and North America. Similarly the warm climate of Gondwanaland allowed much ex change of fauna among Africa. South America, and Australia. Dispersal between Australfa and South America was possib l e via the temperate climates and forests of Antarctica. The ear l y flightless ralites may have taken advantageofthisdispers a l route, resulting in Ostriches in Africa Emus in Australta. and rheas in South America. Penguins, too, may h ave moved among all three continents via Antarctica. At the c los e of the Tertiary the earth's climates cooled. especia ll y in th e polar regions, and became more strongly seasonal. Tropical birds be came r estricted to eq uatori al l atitudes. During the Pleistocene, cl i -HarJclbook of Bird Biolo,q
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Chapter 1-lntroduction: The World of' Birds matTe changes and g l aciers drastically altered the distrib u tions of birds throug h o u t the world. Dry, cool climates alternating with wet, warm ones split the geograp hic ranges of birds and p r omoted both speciation and extinction. Remnant or relict populati ons are one major consequence of histori ca l habitat cha nges. For example, Ostriches now restr i cted to Africa, once roamed throughout Asia, and todies tiny colorful kingfis h er relatives found onl y on the Greater Antilles of the West lived i n Wyoming and France Distribution of Land Birds Birds can be a window on the world in many ways. Knowif'Jg that some North American birds migrate south for the winter, you can use t hem to tell the seasons. For instance, if you saw a picture o r a film from I thaca, New York, and it included a Rosebreasted Grosbeak, you woul d know that the picture must have been taken between May and October. Similarly, you can observe geography u sing birds as a lens. I f you were b l indfo l ded and whisked away to some distant part of the globe, and if you knew your birds of the world well eno u gh, you could tell where you were ; within perhaps a thousand miles or so1 simply by observing b irds. Sci e nt ists looking atthe fauna of the world, including birds have divided the g lobe into six general r egions, with boundaries where the distributions of many different types of animals a ll seern to change. These reg i on s roughly mirror the con tinents, but many boundaries are climati c rat her than physica l (Fig. 1 -52) The following sections descr i be t h e avifauna (set of bird species ) of each region. Palearctic Region The Palearctic region encompasses most of th e large landmass of Eurasia, as well as northern Africa and most of t h e Sahara deser t. It stretc hes from the Atlantic to the Pacific and from the Arctic to the Himalayas, and is by fur the largest region. The major physi cil l tures and habitats run roughly in east-west and are ; f rom north to south: the arctic tundra the boreal forests (also known as conifer ous forests, -or taiga), a chain of deserts stretching from the Sahara in Afr ica east to the Gobi in Mongolia, and a near l y continuous chain of mount ains (from the Pyrenees and Alps east to the Himalayas). The climate ranges from the high arct i c to the subt r opica l stopp i ng short of the true t r opics. Because so muc h of this reg i on is ei t her temperate (free from ex treme heat and cold but experiencing some of both) or arctic, a large proportion of the avifauna m i g r ates south to winter in the trop i cs or be yond. In winter, insect food is scarce, but a small number of birds, such as the ti tmice (chickadee rela t ives), woodpeckers, and nuthat ches, have adapted to remain and continue their insect diet throughout the year When winter is over and the northern lands warm again, insect popul ations i n crease rapidly, and the food available for insectivorous birds becomes tremendous Migrants return in the spring and take advantage of t h e abundant i n sects to raise their young 1 I

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l70 F i gure 1-52. Th e Six Major Zoo ge o graphic Regi o ns: Scientists s tudying the worlds fauna have divided the land a reas ott he globe into srx major regions. At the boundaries of the regions, distri butions of many different types of animals. including bfrds, ch,mge Miln,V of the boundaries are climatic rather than plt>sic
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Chapter 1-/ntrocluction; The WorlJ of' Birds Oth e r typical Pal ea rctic birds include l arks, Old World fly catchers, pipits and wagta ils (Fig 1-54). Nearctic R egion Th e Nearct i c region includes a rctic temperate, and subtrop i ca l North America, reac hin g south to the northern border of tropica l rain forest I n Mexico; i t also i ncl u des Greenland. Although it c ontains many of the same physical featwres as the Palear ctic, the major mountain ran ges of t h e Nea r c tl c (t h e R ocky Mountafns i n the west and the small er Appa l achians to the east) run nort h south adding a layer of comple xity to latitudinal climate b e lts. As in the Palear c tic, east-west belts of a rcti c tundra and boreal forest exist, w ith patches of deciduous forest extending so uthward wherever there is sufficient r ai n fal l t o support it (as i n the southeastern U nited States). Thecenterofthecontin ent, with lowerrainfall, consistsofprairie-cov ered p l ains; areas further west. with even Jess rafnfall are semi-ar id and desert. The southern tip of Florida and the extreme southwestern United States and northern M exico are subt ropi ca l. As i n the Pal earctic, a l arge proportion of the bird s pecies are migratory, takingadvantageoftheabundanceof spri n g ins ects to raise the i r young, b u t l eav in g n orthern N e arctic areas after b reedi ng-many to winter in th e Neotropics. These birds termed Neotropica l migrants include wood-warblers tanage rs, and orioles. T h e springtime return of multitudes ofthesecolorful birds is one of the most spectacula r b i rding events o f the region Despite the diversit y of Nearctic h ab itats no avian families are endemic to the region. Instead the Nearctic is more d i stinctive for its blend of Palearclic and New Worl d groups, w hi c h reflects the conti nent's var i ed histor y; periods of i solation as well as p e r i ods when land bridges connec t ed with South Americ a o r Eurasia (e ith er via Gree n land or th e Berin g Stra i t ) J.71 Figure 1-53. Dunnock: Fnrm erlyc.a /led the Hedge Sparrow th e Ounn1.1ck i5 the best-known representative of the only Ji r d famTI> e:mlemic to tlu: Palearc:li c region the Prullellidae. Allhough the Oun110ck is common in gardens wood lands scrublands and cultivated areas throughout western Europe h1 cenlt
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f.72 F ig ure 1-55. Creal Tit: A member of the same famif), f'aridae ,1s the familiar North American cl1ickadees and the Great 1il w/tl 1 its yellow breast, is a bit more colorfu l than its New Wodcl rplatives. Found throughout murh of the P,Jiearclic and Oriental regions tl1e Greilf Tit readily breeds in nest bnxe < and thus lr,1s been the slib;ecl of man y detailed long-term stodlt:s. I t is very' similar in IJeh;wior to th e chlck ;rdees of North Ame r ica. Dra wing b) Robert Cillmor. Figure 1-56. Winter Wren: The sm.1ll sp unk y tvrens are Jfmos t e ntir ely a New World firmily, but the tfny, stubbytailed Wimer Wren of North Ameri c a rs Jim lounrlthroughnut muc/1 o(the Palearctlr ; region-where It known as the "European Wren or simply a s th e "Wren. In Nort/1 Ameri c a it hreecls mJinl) in motst, coniferous woods often near streams, IJut it frequents a widE lfi!rie r r ol Pillearctic lwbic ats. Drawing b y Cilflrles L. Ripper Ke1inj. McGowan Bird groups shar ed with the Pal ea r cric, in additio n to those al r eady listed under the Pal earct i c region include larks, pipits, nut hat c hes, c ranes, pigeons and doves shrikes, and kingfishers. Although th e p a rticular spec ies r eprese nt ed may differ in the two regions they often are simila r in ecology and basic appeara n ce. For example, a Great Tit ( Fig. 1-5 5 ) or a B lue Tit might come to a bird feeder i n Europe, Instead of a Bla ck-capped Chicka dee or a Tufted Titmouse, but a n y North Ameri ca n birder would noti ce the similar i t ies in behavior and appearance imme diate ly. The New World occurring in both the Nearct i c an d Neotropical regions but nowhere else-i nclude the New World vu l tures, NewWorldquJil limpkin, hummingb irds, tyra n tflycatchers, mockingbirds and thrashers v i reos, b l ackb i rds and orio les, and wood wa rb l ers. Only one of the 78 species of wrens ( Trog l odytidae) occu r s outside the New World-the Winter Wren, known simp l y as the Wren in Great Britain ( Fig. 1-56 ). The disti n ctive turkeys (family Phasianidae subfamily M e l eagr i dinae ) also a r e r estr i cted to the New World ( Fig. 1-57). Neotropical Reg io n The Neotropi cal regio n in c l udes South Ameri ca, Cen t ral America n orth to the northern edge of trop i cal forests in Mexico, and the West Indies" It has by far the greatest diversity and the greatest number of bird species per area of any of the faunal regions, hosting approximately one-th ird of all b ird species foundonearth Aboutone-third of the families fou n d her e are endemic: Tin a midae ( tlnamous), Rheidae ( rheas) Anhimidae {screa mers), Crac id ae l cura ssows guans, and chachal acas), Eurypygidae (Sunbittern ) Psophiidae ( trumpeters), Carla m ldae ( seriemas), Pluvianellidae ( Magellan i c Plover), Thinocoridae (seed snipes), Opisthocomidi1e I Hoatzin) Steatornith i dae (Oilbird), Nyctibiidae ( potoos), ( t od ies) Momotfdae ( m otrnots), Bucconidae (p u ffb i rds ) ( j acamars), Ramphastidae ( toucans and New Comell Lnboratortt of'OmitholoaLJ

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Chapter 1-lntroduction: The World of Biras World barbets), Furnariidae ( ovenbirds), Dendrocolaptidae (wood creepers), Thamnophilidae(antbirds) Formicari i dae (antthrushes and antpittas), Conopophagidae (gnateaters), Rhinocrypt.idae ( tapaculos), Colingidae (cotingas) Phytotomidae ( p l antcutters) Pipridae (mana kins), Oxyr uncidae (Sharpbill), Dul ldae (Pal mchat), and Coerebidae (Bananaquit). The tremendous avian diversity of the reg i on results partly from the types of environments fo und there-particul arly the extensive trop ica l rain forest of the Amazon Basin, which covers about one-th i rd of South America. Raln forests wTth their complex structure warm climate, and abundant r esources, contajn more species per l and area than any other habitat on earth. There are also vast grasslands-some north of the Amazon Rive r but even more extensive ones to the south, the pampas, stretchi n g from Malo Grosso i n Brazil south to Patagonia. These grasslands hos t numerous species of b i rds and other wildl ife. Within the southern grasslands, extending across parts of Braz11 Par aguay, and Boliv ia, is an expans ive r egion, the Pantanal, which is trans formed each year into a huge marsh by torrential ra. ins. The Pantanal has one of the greatest cohcentrat i ons of wildlife on the continent, including numerous wade r s and other water birds, as well as the few remaining Hyacinth Macaws. South America nar r ows so much to ward the sou t h that not much l and area is found within the tempe r ate zone-a climate that typically conta ins fewer species. To the west, the towering Andes, adding an array of habitats at differ ent altitudes, run the length of the continent. A l ong the Pacific coast south of the equator, the cold and fis h -laden Peru (Humboldt) current flows northward from the Antarctic, s u pporting a rich diversity of oceanic birds (see Fig. 1-1 02). This co l d current sets up a temperature inversion by cooling a layer of air directly above the ocean, which is overtopped by t h e warm, tropical air typical of most of the area. The lay e ring creates the Atacama Desert along the Pacific coasts of Ecuador, Peru, and northern Ch i le, be ca use fog and clouds often form, but rarely rain. Although the Atacama is one of the driest deserts on earth and thus has few bird species, it covers a relatively small portion of the Neotrop i cal region. The historica l isolation of the Neotropics also contributes to its extraordinary avian diversity. Over mu c h of the last 60 million years, the Cent r al Amer ican l and bridge between North and South America was transformed into a series of islands by high water levels. As a result, South America was effectively a huge island, its only connection with another fauna l r egion reduced to the island "stepping-stones" acros s Central America. During this time, a huge array of new birds evolved in South America, resulting in the numerous endem i c groups found today A further factor contributing to the plethoril of Neotropica l s pe des is the fluctuating climatlc conditions ( the se ries of "Ice Ages") during the Pleistocene, which created habitat "is l ands" within both the Andes mountains and the lowland areas of the Amazon Basin. I n the Andes, many of the high forests have cool tempe r atures year round, of Bird Bioloi)tl 1-73 Figur e 1 -57. Wild T u rkey: Nii//ve to North America the Wild Turke)' inhabits mature forests, roostin g high in trees at night and by day s cratching the ground for nut s with its large, strong feet. Turkeys alsoeatgrassseeds buds. bulbs herries and some small animals. Wild Turke)'S ,1re the only native New World birds to be widely domesticated. Explorers in the 15UUs found them already domesticated in Me;.;ico , assuming a poswre familiar to ever)' sdwo/chi/d. They also lower and spread theitwings, rolsetheirback feathers, and give loud gobbles1 while rile hare s kin of their head turns red blue and white. Drawing by Clwles L. Ripper.

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1-74 1\ellihj McGowan a n d many bird species a r e restricted to these forests and elevations. During the previous ages when the wor lci was coo ler, t h e for ests on the mai n chain of the Andes were connected by l ow-lying cool forest to t h e forests on peaks lying out away from the mai n chain. Each time the world heated up the cool forests retreated tot he higher e l evations, and those o n the outlying peaks became i solated, separated from the others by a vast expanse of hot l ow l and forest, as they are today. Al though no obvious physical barriers existed, cool foresl specialists found the i r desired habitats i solated f r om similar ones on 'sky islands. These mountain islands acted as genu ine islands, and many new spe cies evolved i n these very r estr icted areas. New species continue to be discovered in these areas even today, as scientists explore the most remote of these mountaintop i s lands. Similar ly. pe r iods of g l a c iation caused areas of t h e high Northern Andes above the tree l ine that are cove red by g l aciers and a humid grassland habil'at termed p ara m o to become connected, a l l owi n g a greater exchange of species ( Fig 1-58 ). I n the Amazon Basin, the cool periods (which were a lso dry ) caused the extensive rain fo rests to shrink to isolated patches known as refu gia These refug i a w ere widely separated by grasslands. Existin g species thus we r e fragmented i nto a n u mber of i solated populat ions, many of which experienced different selection pressures and evolved into new species. When warme r co n ditio n s returned these new species expanded their ranges with the expanding forests. In thi s way formerly widespread species evolved into a number of different species that had ei L her mo r e I i mited ranges or overlapping ranges, or some combinat i o n The current distribution of certain toucan species r ef lects this pattern of speciation ( F ig 1-59 ). Of the many endemic bird families in t h e Neotropics some co n tain just a few species, but others have radiated i n t o n umerous species. Some of the smaller, but more extraordinary, fami lies include the following: rheas (2 species ) : large. flightless ralites of the temperate open country tin a m o u s (46 species) : primitive grouse-like b irds whose eerie call s haunt both forests and pampas (see Fig, 7 2 1 ) ; ti namous a r e the only r alites capable of (light screamer s (3 species): heavy-bodied gooseI ike birds with far-reaching calls (see F ig. 4 18a ) H oatz in (Fig. 1 -60) ( 1 species): an oddl ooking l eaf-eating bird whose yoLmg cl<1mber about in trees on all fours aided by smal l claws on I heir wings (see Fig. 3-41 ) s ee d snipe s ( 4 species): ptarm i ga n l ike birds tha 1 nest both in soul hern l owlands and In h i g h mountains Oilbird (1 species): a large, nocturnal frugivo re, related to nighthawks that uses echolocat ion to reach its nest deep with i n caves (see Fig. 4-53) t r u m peter s (3 species) : large, hump-backed chickenl ike b irds thai roam the r ain forest floor in flocks somet imes foll owing army ants for the arthropod prey they disturb ComeiL L.aboratOflf of Orn.itholoBlf

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Chapter 1-lntroduLifon: The World of' 81rds Cutrent Distribution ot' Pilmmo C l .cier-covered L s e r iemas (2 species): fast, lon g legged, grassland b1rds tha t chase down thei r reptile prey on foot On e of the most important features of the Neotropical avifauna is the extensive radiation of the suboscines ( T yranni) This suborde r of the hug e order Passeriformes i s dist i n guished ir o m the other s ub orde r Passeri (oscines or songbirds), by the relatively simp l e syrinx. No re g ion on earth has as many suboscfnes as the Neotrop1cs; fn fact mosl regions h a v e n o n e o r only a few. Full y a third of the Neot r opica l bird species are suboscines. In general, the Neo t ropical families with t h e most species t end to be suboscine, including the f ollowing : Handbook of Bird BioloBtt 1-75 Fi g u re 1-58. P aramo of the Hig h Andes: In the high northern Andes of Snuth America, a reas above t h e tree line but below the zone of perm anent s now (glaciers) are covered by a habitat I called p ara mo-humid grasslands w ith some shrubs, do ned with lakes and bogs. C urremly, paramo and g l acier-covered land .Jreas (shown in biJc:k) exist iiS r;hains of i sola ted islands o n the hisher pr:.1ks, separated by areas of lowland or mcwnrain fo resr. Durin g the Pleis tpcene lwwever, the cool (}ry clim11t e Jcmmpanying each period nfgl.1cialion allovve
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1 I a. H ypothesized Dispersal of Three Arac;oris from Amazonian Refugia KevinJ, McGowan h. Current Ranges ofThree Amazonian Aracaris Cornell Laboraton1 of0rn1tholo81J

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Chapter 1-lntroductlon: The World of Birds Figure 1-59. Amazonian Rain Forest Refugia and the Distri bution of Aracaris : In the Amazon Basin, the cool dry glacial periods of the Pleistocene c.1usf'd the extensive mln forest<; to shrink to isolated patches separated by gmss/ands. T11ese iso lated patches are known as refugia Existing spi!Cies rhus were fraymented into a number oi isolated popuf ,,tions, many o( which experie n ced different seler;tion pressures and evolved into n ew species. When warmer conditions returnec/-be tween the Ic e Ages, and in the rirne si nce the l01st glacial new sp(lcies expanded their mnges with the ex panding foresrs. In some cases, such as the aracaris11/usl mted h ere, a widespread, a ncestral specias apparent/) evolved into a number of species with more limited ranges. Aracaris are slender, small to medium-.siled toucans. The thr ee forms cfishere, the Green Amcarl and two subspecies of the Let tered Aracari l consider ecl subspecies bec wse I hey interbreed along their common bounclury), difff!r mostly in the C<1lo r of the bill Tllese 1/Jree aracmi are so similar lhatlheir t.lxonumic 1 .77 relationships remain unclear Clemel)/s 1 2 000) considers Ptero g l ossus inscrTptus humbofdli a subspecffi'softhe GreenAfacar/1 instead of a subspecies of the Lettered Aracari as shown here. a. H y pothesized Dispersal of Three Aracaris {rum Amazonian Forest Refugia : Colored areas inc/ic,Jte the presumed lo c ario n s oflargrdorPst refusialn tropical South andCentmlAmeric;a dur ing the cuol dry glacial period; of the Pleisto c ene Qark areas indfcilte mountains above 6 600 feet (2,000 m). Researchers hypothesize that a sif)gle species was fmRmentecl' into populations in the Guiana Refuge, the Be/em Refuge, a nd a chird site in the upper Amazon ( possibl y a gtoup of refuges known c1S I he Eastern Peruvian Refttgia) In isolation they e.1c h el/o/1' 00 into n ew forms. As the forests expanded during warmer times, the new forms expanded their ranges llS indicated by the arrows. b. Current Ranges of Three Amazonian Arac.uis: n1e cu r rent ranges of these three forms, indic11ted hy the different t ypes of shading, overlap very lillie. Afler Naffer ( 19 7 4 1 Cop)' righl Nut1.1/l Ornithological Club. Figure 1-60. Hoatzin: The bizarre. c hunky. pheasant-sized 1-toaWns with their b}ue1 bare facial skin brigh t red eyes, and raggerl ere.
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1 Figure 1 -61. Wood creepers: Found in forests. forest borders, and mangroves throughout Central and Souti1America, the sub oscine 1voodcreepers (family Dendrocolaptidae l resemble the unrelated oscine creepers (family Certhiidae: Brown Creeper of North America and treecreepers of Eur.Jsi.1) in lx!t h appear ance and habits Using its stiff tail as a !)race, a woodcreeper hit c hes Its way along bmnches and up tree trunk5, peering and probing for insects and other animals IJnder b.1rk, In rree crev ices, or a mong mosses and epiplwtic plants (pli!nts, such as orchids and bromeliads, that grow o n plants). T il e tail is well-adapted to wedge Into irreguli!rltles In the bark ,15 the bird climbs, because the feather s hafts extend beyond the vanes and curve downward. The 51 species Me remilrkably similar to one another in appearance, their rufous or olive p lumage usually or spotted with ligh t er colors in the head and breast regions. However; as can be seen from tl!is plate of 17 species from Panama, bill shape varies widely. from short and pointed ( bird 1 5): t o long, strong, and woodpt..'Cker-like with v.1rying Jmounts of c urv a tur e (for instance, 7, 12, I J .llld 14); KevinJ. M cGowan and to slender arid strongly downcurved, as in the scythebil/s ( I 6 and 17). These l>i/1 variations undoubtedly reflect subtle differences in foraging methods. A few species, no t ably the Plain-brown Woodcreeper, are regular followers of army ants, Ci1pturing rhe i nsects flushed as an ant swarm passes by (see Ch. 9, Sideb.1r 3: Ant Followers). Species shown h ere are (1) Ruddy Wood c reeper, (2)Tawny-w inged Wood cree per, (3)Pia in brown Woodcreeper, (4) 0/iva ceous Wood creepcr; (5) Wedge-billed Wood crecper, ( 6 ) Spotc rowned Wood creeper; (7) Srrc.1k-hcaded Woodcreeper, (8) Buff throat ed Woodcreeper (9) Long-tailed Woodcreeper, (10) Spotted Woodcreeper, (11) Straight-billed Woodcreeper, (11)Strong billed Woodcreeper, ( 13) Black -band ed Woodcreeper, (14) Ami1zonian BiJrred-Woodcreeper, (15) Black-striped Woodcrt'Cper, ( 16 ) Rt'CIbilled Scythebi/1, a nd (17) Brown billed ScyLhebill. Painting by John A. Gwynne (adapted), from A Guide to the Birds of Panama by RobertS. Ridgel y and John A Gwynne, /989, P/<1/e 19. Published b y Prin ceto n University Press. Used with permission Come// Laboratorlf of Ornltholoe t t

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Ciwpter1-lrrtroduction: The World of Birds woodcreeper s (51 s pecies): similar-looking, rust -co l ored birds with a w i d e arrayofbeakshapes ( Fig 1 -61);they forage1nbark much like th e unrelated Brown Creeper of North America antbirds ( 197 species): smal l, i nsectivoro us, forest birds; some specialize on following column s of army ants to prey on the inse cts and other arthropods stirred up b y the numerou s movfng ants (fig 1-62; a l so see Fig 7 -28 and Ch. 9, S i debar 3: Ant Followers) a ntthrushe s and antpittas (60 species): small, drab birds with l oud, ringing songs; ma n y h aunt the rain forest floor a nd may follow a rmy ant swarms ovenbird s (24 0 species ) : a diverse group, espe cially nu merous in t e mperate South America n a med for the oven-shaped, clay nests of some spedes (see Fig. 4-1 18 ) tapa culos (52 spec ies): antbird relatives with cocked tails, frequenting more southerly, open, and dy areas than antbirds Themostnumerousof all suboscines a r e the rlycatchers.Aithough man y "fly-catch1ng" bir ds a round the world are called fly ca tche r s," the huge fami l y T y rannidae (ty rant flycatchers) is enti rely restrit:ted to t h e New World. Only a handfu l of the n e arl y 400 tyrannid species make it to the Nearctic, a n d they are all rather similar, genera li zed a e rial in sec tivore s {see Figs. 2 15 and 7-43) In the Neotropics the tyrant f l ycatc her s h;we evolved to fill a large numbe r of ecolog i cal ro les, spec i a l izing into a d i verse assemb l age (Fig. The Neotropical avifauna a l so includes man y bird groups that are shared w i th the Nearctic or Hoi arct i c regions. I n the near future, DNA co mparisons ma y prov i de useful clues on the o r igins of these groups, b u t for now scie n tists ca n onl y specu l a t e based on the distr i bution of species. The overwhelming number of spec ies of both hummingbirds and tyrant flycatchers in the Neotrop i cs compared to the Nearcti c suggests that both these groups origi n ated in the Neotropics and lat e r reached the Nearct i c. Other shared g r o ups include New Worl d vul tures waterfowl, hawks New World quail pigeons, owl s wood peckers, vireos, jays, wrens, thrushes (Turdidae), New World war blers (Paru l idae}, tanagers, cardinals (Cardinalidae), and blackbirds and New World orioles (lcteridae). Regardless of where thes e gro ups originated rnost of them rad i ated in the Neotropi cs to such an extent that they currently contain many more.Neotropicalthan Nearct i c spe cies. Two important families, t h e fru i t-eating tanagers and th e closely re l ated, insect-eating New World wa rblers, contain numerous spec ies. A few members of eac h migrate to t h e Nea rctic to b r eed, but these are essentia ll y Neotropica l groups. Although both titmi ce (Par iclae) and nuthatc hes ( Sittidae) are widespread throughout the rest of the worl d they have no Neotropkal m e mbers. Most of the non-endemic b ird fami l ies of the Neotropics are shared on l y wilh the Nearctic or Holarcti c, b u t several groups, such as the parrot s and trogons ( Fi g. 1 64 ), are found in tropica l r eg i ons of Bird BioloB'I T Figure 1 62 W hit e-plumed A ntbir d : An/birds are sman often boldly pat terned l1irrls that lrequenrl y moV<' through tile rain fores t in mixed-species foraging flocks. Most species pick ins ects and other arthropods from foliage wit/1 different species feeding at ditl'erent l ev els in the fores1. The erovp gels its name a iew specie$, int'ormally termed th e professional '' which spe c ialize on following columns of arm> ants they m11rch .1cross tl1e {ore$1 t1oor. These a ntiJird s prey on arthropods slirred up b y th e moving ants. The White plumed An/bird, striking wilh its while face .1m/ crest bl,?ck head, /1/uegra y back ,1nd wings. and ches tnut breast and tail, is a m o ng the most common nlthe professional antbirds in nort hern Amazonia. Photo hy Dollg Wechsler / VIREO.

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1 a Vermilion Flycatchet e. Spectacled Tyrant Figure 1-63. T y rant Fl ycafc her D ivers ity: The suboscine famil y Tyrannirlae ( tyrant flycatchers) found only in the New World has more species than any uther family of birds. or the nearly 400 species, Just over three dozen rerJularly breed in the Ne arctic. Most of these-including most 11ycatchers, some kingbirds the Great' Crested Flycatcher, wood-pewees and phoebes-are similar in general shape and aerial insect catching behavior I n the Neotropics the tyrant flycatchers have radiated into a wide array of ecological roles making up roughly 70 percent of all bird species, and 20 co 25 percent of the passerines. Some of the more spectacular tyranl flycatchers pictured here are: the brightl y colored Ver milion Flycalcher ( a ) and Many-colo r ed Rush-!} rant ( i ) the long-tailed Strange-tailed Tyrant ( d ) and Longtailed Tyrant (g); the bizarre Royal Flycat cher (j), which flashes its fan-shaped oumge crest only dvring a/arm or aggression; the Cock-tailed ( c ) a n d S h arp-tailed ( h ) tyrants with m odified tail feathers; the miniature Shan-/ailed Pygmy-Tyrant ( f) ; and the Spectacled Tyrant ( e ) with its conspicuous yellow eye ware/e. jJ.Long-tailed Tyrant Kevi n J McGowan k. White-crested Spadebi/1 n Shan-tailed field-T)t rant f>' rant llycatcherslive in nearl y every habitat-from rain for est and savanna to the high treeless paramo: and forage .1t every forest level -from the gro1md, understory, and forest edge, to the canop>' and above. Like the Nearcti cbreeding tyrannids many NeotropicaltyrannidssallymJI rograb fl y ing insects from iln exposed perch, hut numerous var/;rtions exist. Some have even evolved to eat fruit, fish, young birds or frogs. Some fly catchers reach fur insects while perched or hovering, whereas others fl)r out to gmb in sec/$ from bran ches, foliage, or even the surface of water. The Cliff Flycatcher ( b ) looks and behaves like a swallow, perching un cliffs to searrh for aerial insects. The Boat-billed Flycatcher( / ) has a /wge wide beak with which it may c.1pture large insects, and the tin y White-crested Sparlebi/1 (lc) uses its wide t1at beak like a shovel scooping insects off the undersides of leaves. The longlegged Ringed An/pipit ( m ) walks on the rain forestl1oor, looking up at the undersides oi leaves and then hopping up to grab any insects it finds The Short-taNed Field-Tyrant ( n ) is also terrestr/,11 Original paint ing by john W. Fitzpatrick from Tray fur and fitzpatrick ( 1982). Reprinted with permission of fohn W. Fitzpatrick. Cornell Lnb o raton1 ofOm ltho loBtJ

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Owpter 1-lntroduction: The World of Birds throughout the world. Bi r ds d istributed in thiswaya r esaid t o be pan tropical. Because so mu c h of the Neotropical region is cove r ed by lowl and tropical forest fr uit s a nd flowers are particu l arly .abund ant, and frugivory (spec i alizi ng on eat in g fru it) is particularl y common Entir e famili e s of frug i vorous birds have evolved, s uch as the cotingas, manakins most of th e tanagers and the toucans ( fig. 1 65). Abundant flowers feed the l arge number of hum mingbirds a successf ul gro up conta i ning more than 300 spe cies, all but a dozen of which are fou nd on l y in the Neotropics Easy food, such as abunda nt fruits, a l lowed many Neotrop i cal birds to evo l ve a mating system in which the males take n o part i n rais ing young, but instead display elaborately for mates-often cong r egat in g in traditional disp lay areas that females visit The colorful Neotropical manakins (see F igs. 6-42 and 6-47) a n d cotingas-includin g the fantastica ll y plumaged urn brellabirds (Fig 1 66 ) and the gaudy cocks-of -th e-rock (fig. 1-67)-are c hall enged only by the New Guinean birds of-par adise for having the most e lab orate plumages and displays i n the avian world. Afrotropical Region The Afrotrop i cal region includes Madagascar southern Arabia, and a II of Africa south of the Sahara. I solated by water as well as b y sand-th e vast Sahara a n d Arabian Deserts-the region has man y endemic fam i lies and is second only to the Neotropica l r egion in the numb e r of species Although much of the r egion is relatively warm, it is a lso dry, r eceivi n g only about ha l f as much rain as South America. As a result, a greater proportion of the region i s covered by desert scrub, g rassl a nd and savanna, and the areas of tropical rai n forest are somew h at more restr i cte d t han those of the Neotropics A l though mountainous re gions a repr esent, there Is no of Bird 11 Figure 1-64. Slaty-tailed Trogon: Tro gons are chunky, colorful birds that r end to perch on branches in a characteristic vpright posltlre with their long, square rail pointing down. They often remain perfectly still for long periods of time. Thus, in spite of their brilliant colors, they can be difficult to see, but their frequent vCO \ V, cow, cow call ma)l give away their loc-ation. These fruitand insecteaters dig their nest cavities in clead tree s o r in active ter mite or w,1sp nests. Although mostrrogon species live i n the Neorropics, the y ,,re also found in tropical Africa and Asia. The Slaty-tailed Trogon i s found in rain forests from Arlex ico t o Ecuador. Photo by Marie Read. Figure 1 -65. Choco Toucan: Toucans, instantly recognil'ilb/e wit/1 their enor mous, gaudy bills, live in Neotrop/ forests, n esting and roosting I n t r ee cav ilies In body shape and some aspects of their eco logy, the y are convergent with the Old World hombills (see Fig. 1-82). T o u cans use the lips of their large light weig ht bill to reac h out and gr,lb ripe f rvits They then flip back their head and toss the fruit down their throat. Although primarily fwgivorous, touc:;ms also eat small animals, indvding the eggs and nestlings of other birds. The Choco Touca n striking with its yellow and c hestnvt beak yellow iace and front black back white wmp, and red under tail coverts lives in 111et forests on the Pacific s lopes o( western Colombia and Ecuador. Photo b y 5. 1-to/WJREO.

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Figur e 1-66. Lon gw attled U mbr e l l a bird; Like other memiJers of the sub oscine Cotingidae tlmbrellabird s are large, stocky fruit-eaf.ers of the Neo lropical Forests. Many cotingids are qeautiful and in teresting, w ith bizarre courts hip rituals. The L ong-wM tl ed Um brellabTrd, a bitlargerthan an 1 \m erica n Crow, is bla ck with a bluish g loss. A.J.1/e.s have a lmge umbrel/a-sh<1ped crest on the h ead and a long, fleshy. inflatable wat(/e-covered with ing down from the throat. Females are simiiM with a smnller wattle. Males dis play in the rain lores t canopr by ing their crests, int1ating their wattles and ;vmplng from branch 10 branch while giving 11long low gr uf)l Or. Each male clears leaves anti debris fi-om a small area of groun d to form llir own disp/;l)lcourt. When a femal e arrives to choose d mate the males erup t int o a cacop h o n yofca/Js a nd displays, bur much of their "s how ing off" consists of slJltic posturing di r ected toward the female. Typically just a few males do most olthe malina The female performs al l of the nesting activities-sticking her cu p ne-st of mud to a rock wall near the Ml.t
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Chapter'/ -Introduction: The World of Birds region i s above 3,000 feet, co mpared t o less than 1 7 pe r cent of the Neotropica l r egion. Arou n d the equ ator in the west ern two-thirds of the co ntinent, i s the l owla nd trop i cal rain forest of the Congo Basin. As in the Amazon Basin the dry, cool g l acia l period s of the Pleistocene created a series of r ei ugf a h e re, whic h are thought to h.we served as centers for species d i versif i catio n across the east-west ill< is of today's equatorial tropica l fo rests. Farther from the equator, and in parts of t h e plateau regions, a r e vast areas of open woodla nds,s(lvannas, a nd g rasslands. Chari)cter isti c bi rds of the grassy areas are ci s ti c olas (small drab, insec t ivorous warble rs), w e a v er s (a d iverse group o'f co l orfu l seed-eaters, many of which weave large, co m plex n ests), and wax bill s (another g r oup of co lorful seed-eatersi see Australasian regi o n fo r more i nformatlon) Deserts and semiarid scrub lands, with sparse vegetat ion a nd scattered trees s u c h as acacia (and in the east, baobab), are found in three main a reas: ( 1 ) i n t h e Sahel region j ust sout h of the Sahara, (2) in the northeast, between the Gu l f of Aden and no1thernTanzania, a n d (3) in the southwest--the Kalahari Desert r egion. Typ i cal b irds of these open areas are larks, bu s tards, a n d cou rsers. Bus tard s a r e large, heavy-bod ied, flat-headed bird s with l o n g legs a n d necks (Fig.l-68). They often assume bizarre postures dur i n g the i r e l aborate cou rtshi p d i s plays. C ourser s are slender, p lover-lik e ground nesters that sometimes cool their eggs or yo ung by pa11ially b urying them in sand or by bringin g water to the nest in t h e ir breast feathers. I n addi t ion the trees support a g reat divers it y of ot her species, including many Palearctic migrants. Families endemic t o the Afrotropica l region include the fol lowing: Struthion i dae ( O stric h ): t h e largest living bird, this famil iar r atite of deserts and savannas is a lmost entir e l y herbivorous; Ost riches breed commu n ally, wTth several females l aying eggs in t h e sam e nest B a laeni ci pitida e ( S hoebill ): a large, stork1 ik e water b ird with a huge shoe-shaped, hook e d bHI for seizin g big fish (Fig 1-69) Figure 1-68. Kori Bustard: Stout birds with lung legs and necks, the grounddwelling bustilrds freqaent ,1 vMiety of open habiws, {rom >emi-f lesert and gr.Jssland to def)se scrub Tl1ey eat a wtriety of plant .tnd .111imal foods rangIng from t1owers, and !Jerties to insects, frogs, and small mammals Although most spedcsliVI' in Africa, a few are found 111 the Oriental Austrahtsian and sou(lwtn Paleilrctic reeiof1$ The long lived Bustard< range in size from as II as .1 Ring-hillced'Gull ro as ltJrge as a Tundrt1 Swan. The y have suong leg s and feet designed for running, with three tOes and no Their plumiJge i s cryptic,11fy co/ured ill buff or brown overall. Some o( thp smnller s pecies perfonn dru.miltic ilerial courls/Jip rlispl,,ys: males or the 8uff.cre.sttJd BustMd fluf) thefr feathers and t1y straight uplnwtheair. sometimes high ils I()() ieetl30.5 mi. then parachute back down In eilrth. Thf' lm'Jie Greitl ilnrl Koti Bustardstpicturod here), displol)' rlrt the ground Tl1ese courting males co c k theiroutspreacl (,)f/s forward inflat e thei r gular r thmal/ sacs. retract their hf'ads, a11d elevate the light colored neck and ltl!derlafl a (('athered entit y rhat only I}.'Jrely reseml>les 11 birr!! Dr
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t-84 Fig u re 1-69. S h oebi/1: The only member of its family, the Shoebill(.1/so known as the Whale-headed Stork) has a huge, :;/JOe-shaped bill with a prominent hooked nail at the lip. Standing nearly 4 feet (1.2 m l tall the Shoebill hunts freshwater sw,Jmps of central anrl east ern Africa by waiting motionless for long periods watching the water for unwary fish, .1mphibi.111s, aquatic snakes, and small birds. Its nest is a large flaflened mound of grass on floating plants1 hid den among d ense vegetation. Nestin g Shoebills regularl y bring water to the nest in their large bills pouring it onto their efi8S and down y yo ung to coo l them. Photo by t\. Morri:;NIREO. KevinJ. McGowan Figure 1-70. S e cretary-bird: n1e sole meml1er of its family, the way and black Secretary-bird is distinctive with its elongated centra/tail featl1ers and long, loose crest of quills. Over 3 feet (1m) t all, this long-le88ed hfrrl -ofprey hunts b y striding through the savannas and grasslands. stamping its feet to scare potential rrey-large insecrs, reptiles rodents and other small animals-out of hiding. It is known for capturing snakes and then crushing them against the ground with its blunt talons Despite being ground hunters S ecrecary-birds 11y nnd soar well, performing spectacular aerial cou rtship displays with undulating dives and croaking calls. n1eit' used year afterye.1r, is a large pfatfom1 of sticks in the top of a shrub or tree, often in the flat-topped a<:acia trees co mmon thmughouttl1eAfricansavannas Drawing by Robert Gillmor Cornell

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d1apter 1-/ ntroduction: TI1e World of Birds 1 S copidae (Hamerko p): a stor k-like water bird whose shaggy, crested ..... nape a n d stout, tapering b i ll make the head appear hammer -shaped .} '-"'-. (see F ig. 8-38) ,.._, S
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1 Figure 1-73. Vulturine Guineafowl: n1e large, c hi cken-likegu in eafowl have dark plumagedisUnctively spotted and s trip ed with white. Thebareskinoftheheadand neck is ofte n brightly colored a nd nlil ) be adorned with wattles. Some species have bony casques or feathered crests o n the head. Gu in eafowl are gregarious when not breeding, oflen gat h ering into flocks of 50 or more birds. Theirra ucous voices can be h eard from nearly every African h abita t from dense forest to semi-desert. The Vulturine G u fneafowl has particularly beautiful p lumage, in cluding brilliant blue on its breast and back It occurs i n dry, scrubby r egions of eascem Kenya, Somalia, a nd Ethiopia. Photo b)' Marie Read. Kev in J McGowan Figure 1-72. S c halow's Turaco: Together with plantain-eaters an d go-awaybirds, turacos m,ike up the family Musophagidae. These crow -sized, l ong called, arboreal birds are weilk preferring t o mn a lonf!, branc hes muc h like squirrels. Their ou t e r toe can be rotated forward or/Jack, but is often used a t rightangles to the main axis of the foot-allowin g the m to nimbly traverse branches in se,lrCh of fruit foliage ;md buds. Their h arsh, bark i n g calls are fa miliar sounds in the African forests. The forest-dwell in g turacos and plantaineaters are usuaii) 'Soitgreen, v i ole t blue or some comb ination of these colors, with crimson on the wings. Tfley also have colorful crests, eye rings an d bills Tl1e gray ,md w h ite go-away-b irds inhab it more ope n dry woodlan d s Thts family of birds i s famous for its unique pigments, found in no other animals. The reds are produced by a copper-containing pigment called turacin, and tile greens, by turacoverdin. Schc1low's Tumco, found in the humid forests of south-central A frica, is mo s tl y g r een with cri mson primaries, a scar l e t eye ring, and a green crest tipped with white. Photo by P. DaveyNIREO. Figure 1-74. Mount Apo Sunbird: Tfle tiny s unbirds-som e s mall er than a R uby thr oated Hummingbird-have long. s lender, downcurved bills, and the males of many species are brillhmt l y colored otie n iridescent Most of the t24 species inhabit Africa and Madagascar, frequenting a vari ety of h,1bit.1ts. Some, however, ate found in the Ori entat Australasian and southern Palearctic regions. Although the family nam e ( Nectariniidae) hints that sunbird s feed on nectar, they also eat insects. Short-bilk>d species t end to eat more than nect,lt; whe reas l o ng-bill ed species pri marily feed o n the nectar of tubul ar flowers much like the unrelated hummingbirds. Like hummingbirds, sunbirds act as pollinators of flowers, and their bills have evol ved t o match the s hape of the flowers they visit. U nlik e hummingbirds, however, sunbirds c,1nnot hover to feed on the wing. In s t ead they cling, ofte n upside down to a flower a s they probe for nectar. S h own h ere is a Mount Apo Sunbird from the Philippines Photo by Doug WechsterNtREO Comell of'Omitholo&tl

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the venom before eating them. Some species are cooperative breeders that live in complex societies. Roller s named for their rolling o r rock ing dives during courtship f l ights, appear somewhat lik e bee-eaters, but with more muted p l umage colors mainly in shades of b l ue pink, ol ive, or chestnut. They often forage like blueb irds, perching and then f l ying to the g round to grab large arthropods. Particularly int eresti n g in theirhabitsare theox peckers ( members of the starli n g family, Sturn i dae ) and the nonpasserine h oneyguides. The sociable oxpecker s also called tickbi r ds," climb upon large Af rican mammals as they graze, removing ticks, insects and the scabs of skin wou nds-a relationship benefitting both the birds and their hosts (fig. 1 75 ).The honey g uides are peculiar i n their ability to digest wax, especially beeswax in addition to t heir insect prey. At least two species use dis tincti ve cal l s and be h av i ors to lead humans baboons or honey-badgers to bees nests-feeding on the wax and larvae once the mammalian helper has opened the nest for its honey The island of Madagascar, off t h e east coast of Afrlca, deserves spe c i a l mention. Although it shares most of its f<1una with mainland Africa at th e family l eve.l, i t has been isolated long enough to have evolved a number of un i que families and a host of endemic species. Its h abitats, a lthough much denuded by humans var y from d r y woodlands and scrub in the west, through c entral highl a nds to rain forest i n the east. Fami lies uni que to Madagas ca r and the surround ing islands include: mesites (Mesitornithidae): rail-like ground -dwelling birds, aboutthe size of a Mourning Dove ground-rollers ( Brachypteraciidae): solitary, terrestria I insect -eaters with stout b i lls short wings, and moderatel y long legs and tai l s ( Fig 1 76 ) Handbook of B ird Bio loglj 1-87 Figure 1-75 Red-bi lled Oxpecker s on a Black Rhinoceros: The bluebird s /zed oxpeckers inhabit savannas throughout muc h of eastern and southern Africa, feeding on ectoparasites that infest the ski n o F large mammals. They forJge in small flocks, hopping and climb ing over the bodies of grazing zebras giraffes, buffalo, rhinos, warthogs, antelopes and even domestic cattle. n1e m ammals are usually indifferent to, and indeed b e nefit from, the birds' gleanings. Oxpe ckers have short legs; sharp, c urved claws; and stiff tails that act as braces-all adaptations helping them to cling to their hosis. Their bills are laterally flattened, and the birds open and close them rapidly in a scissor-like action as they push the m through the furor over the naked skin of a mammal removing licks and other skin parasites. They sometimes capture flies that land upon the host's skin and drink fluid from around the h ost's eyes. Oxpeck ers breed cooperativel y and, like their starling r e / ativt;>s, roost co mmvnall y at traditional sites. Photo by Marie Read.

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1.88 Fig ure 1-76.!d Ground-Roll er: The five species of make up the family which is e nd emic to Madagi.iSc:ttr. These stocky, ground-dwelling birds h ave 1.1rge heads and eyes, stout bills short wings and relative!) long tails and legs. All are insectivorous occasionall y pre ying on small lizards, snakes, or snails. n1ey nest in tunnels dug into the sid e of a bank. Like most oth e r birds of Madagascar, their populations are in severe decline due to human-induced habitat df!Struction. The Long-tai/c.od GroundRoller, shown !Jere, is a boot the s iz e of a magpie and is mottled brown and b l a c k above with blue on the wings and outer tail feathers and a bl<1ck band a cross pale breMt II inhabits desert scrub. whereas the other four species liv e in dense e"ergreen fotes/5. Dta wlng b y N. A Arlott from A D i ctionary of Birds. edited b y BruceCampbel1.1nd Elizabeth Lack, p. 257 Copy right1985 The Brit ish Ornithologisl51 Union Reproduced with the kind permission of the British Ornithologists Union KevinJ. McGowan CuckooRoll e r ( l eptoso matidae): a sing le, now-sized, arboreal spe cies w ith a sto ut, b r oad bill asi t ie s and fa lse sun birds ( Philepittida e): s ubos d nes, the asities feed on fr uits, and the false sunbirds, on in sects and nectar vangas ( Vangidae ): a diverse passerine group of 1 4 shrikeI i ke species; most are gregario u s and noisy, g leaning insects and other s m a ll anima l s as the.Y move through the trees ( Fig. 1-77) Madagascar was th e h ome of the Gran t Elephantbird ( Aepyornlthidae), a huge, flight less creature long exti nct, whi ch weighed ha l f a '[On and laid two-ga ll o n (eight-liter ) eggs ( see F i g. 5-48). The Dodo (Raphidae), a f l ightless bird t h e size of a turkey lived on lyon the island of M auritius, east of Madagascar; it has the unhappy dist inction of be ingoneohhefirstbirds known tobeeliminated by "civili zed'' humans, in the 17th century ( see Fig. 9-75) Orien1al Region Th e Oriental reg i on includes of Asia so u th and east o f the Himalayan M ou nt ai n s (India and Sou t h east Asia ) as well as s-outhern Ch ina and the islands of Indonesia and the Phil ippines. Although the Himalayas form a clea r bounda r y with much of the Palearctic region the distinction is less clear in C h ina where some mixingoftheOri e ntal and Palearctic faunas occurs, w i th t hrushes, accentors, dippe rs, and tits being shar ed between the tvvo r egio ns. Similarly, the Australasian and Oriental faunas grade into each o th er in Indonesia. The boundary has been chosen somew hat arb itr a r ily, just to the east of the isl a nds of Timor and Sulawesi where the proportions of t h e two faunas are rou gh l y eq u al. T h e Oriental region is mostly tropica l and subtropical much of it in rain for est, altho u gh t h e r e a r e s ma ller areas of drier h ab itats such as dry forest, scrub, savanna, and desert. less iso l ated than the other avifauna regions, the Oriental hosts o nl y three endemi c (amilies the lrenidae ( arborea l so n gbirds called leatbirds and fairy-b l uebirds), the Megalafmidae ( Asian Barbets), and the Aegithinidae ( ioras ) The ori ole-sized l eafbirds mostl y g r een and yellow, feed mainl y on insects and f ruit. The two fairy -bluebirds n amed for the brilliant blue a nd black plumage of the m ales, are slig htl y Figure 1-77. Helmet Vanga: The vanga famil y (Vangidae) consists of 14 species, all enc;femic to Madagasc a r Gr e garious s hrlke.fik<'! birds vangas move through the trees in nols>' flocks, capturing insects Most species have heavy bills, which ar e hooked In s ome. The ir plumage is bold!) pa tt e rned and sometimes glo ss)t, and v ar i e s in color-being black ,md white blue and white or a c ombinMion of black rufous, and gray. The 1-/e/metVanga, shown herf!, has bc)/r/ l)la t; k-and-r!l(ous p/un Jage and a greatl y enlatged bill, u l hich it uses to c apture insects as well as tree frogs and small reptiles. Drawing b) C. f. Ta/IJoiKelly, from A Dictionary of B ird s edited by Bruce Campbell and Elizabeth Lac k p 6 I 9 Copyright 198 5 The Bri(ish Ornitlwlogists' Union. Reproduced v iti! the kind permission of the British Ornithologists Union Come II Lahoratorq of OrnitholoBtl

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Chapter 1-lntroductioiJ; The World of Birds l arger, feedingprimarilyon figsandot herfru its (Fig. 1-78 ). The A s ian barbet s are chu nk y birds slfghtly smaller tha n a Belted Kingfisher with thick bills and gaudy, clashing col ors; many are green with red, blue, or ye llow markings. T h ey feed mostly on fruits and insects (fig. 1 -79). The four species of iora s are small arborea l songbirds that sear c h leaves often in dense foliage, for insects. Males of some species perform elaborate courtship displays with vertica l leaps and para chuti ng flights. Birds of the Ori ental r egion-especially in and near India resemble those of tropica l Africa more than t h ey resembleanyotherfauna l group, r eflec ting the long period in geolog i c history that Indi a s p ent attached to Afr ica via M a dagascar. The fact that many families {for examp le, hornb ills, hon eyg uides broadbills bulbuls, sunbirds and weavers), but few species, a r e s h ared between the O riental a n d Afrotropica l avifau nas i n dicates the long pe riod of time about 85 mi ll ion yearsthat the y have been evolving sepa rately. Particu l arly well -represented i n the Orienta l reg i on a r e member s of the family Phasianidae : Old World quail, p h easants, partridges a n d grouse-as well as the spectacu l ar peafowl (see Fig. 3-6). The domesti c c hi cke n has descended from the Red )ungl efow l of this family ( Fig. 1 -80) Addi t i ona l fami l ies with numerous species include pigeons, corvids, sunbirds, severa I families of f i n c hes, a n d t h e fo ll owing: H andbook of' Bird Blolo_qq 1 Figu re '/-78. As ian Fai ry-blue b ird: Togeth11r with the lea/birds fa i ry-blue birds make up the lrenidae a of songbirrls endemic to the Orienral resirm Male iairybluebirds lwve l>ril li,,,,, mctdl!ic blue plumase with con t rasti ns Jreas uf velv e t y IJI,1ck; fem.1lcs are similar, wllhsomewha r duller co lors. Slightly larger than orioles, lairy-b!tre birds lnh,,bif the C
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1 Figu re 1-80. Reel } unglefowl : T/1e lami/.V PhasianidaC>-pfwi.lsants partridgos ljfOU>e, IUtkc:y> pi/1. Phntn b y Doug Wechsler!VIREO Kevin J. McGowan babble rs: a diverse group of g r egar i o us, i nsectivo r ous birds ma n y of whom h ;we compl ex socia l systems and b reed cooperatively pitta s : secre ti ve, s tocky b i rds of the tropical forest floor with long legs and short tails; many a r e brightly co l ored be low and cryptic abov e; pitta s use the i r h eavy bills to ca t c h a variety of insects and other s mall animals, esp ec i ally snails (see Fig. 7 28) flowerpeck e rs: small often-co l orful songbirds, mu c h like s unbirds in t heir busy, noisy behavior as they forage high i n the trees on b e rries, nectar and ins ects b r o a d bills : chunky, bri g h tly co l ored fores t birds most close l y r e l ated to cotingas and tyrant flycatchers they use their wide, flat, co l orful bills t o sna t c h up large ins ects; 10 of the species ofbroadbi ll s are found in th e Oriental region (Fig 1-81) Cornell Labora tont of'

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Other birds c hara c t e ristic of the reg i on includ e owls, p a rrots, woodpeckers, s hrikes, thrushes warb l ers, m y nas, and Old World fly ca tch ers. In add iti on, m a ny Palear ctic mig rant s overwinte r in t h e Orienta l re g i o n Two p a rti c ularl y biza rr e bird families fou nd in the O r i e ntal regio n a r e th e hornbi lls (Bucerotidae) a nd t h e frogmouths ( P oda r g idae). The h ornbills have huge, down-curved bills topped by a peculiar casqu e (Fig 1-82), a n d are famous for their uniqu e ne s ting b ehav ior in which the female seals hersel f inside t h e nest cavity with the eggs and young nestlings and depends on th e mal e to bring food (see Figs. 3-32, 8-44 and their associ ated t ext sectio ns). The f rog m ouths r e semble the i r ni g h t j a r r e l atives in both cryptic a ppe arance and behav i o r ( Fig. 1-83). These nocturnal forest birds sall y out from a bra n ch a nd use th eir wide, "frogli ke" beaks to s nat c h up s mall a n imal prey-includ i ng mice frogs, and sma ll birds-from the g round o r bra n c hes. A u stra lasi a n Region The A u st r a lasian r egio n e ncompasses the islands south and east of the Oriental region includin g the Molu cca s New Guinea, Australia Tasmania, Handbook of Bird BiolotJLI 1 Figure 1-82 Rhi n oceros Hornbilf at Nest C a vity: Found throughout the Oriental and Afrotropical r egions, hombills hav e long t ails and strong, decuNed bills with a distinctive casque on th e top. Many species h ;rve bf,l c k andwhite plumage but the bill is ofte n colorful, and the head ma y have brightl y col ored ,1re,1s of bare skin or feathers. Hornbil/species are found in a variety of habitats, and vary f rom 2 t o 4 feet (38 t o 126 em) in length. They ea t large insects and o th e r arth r opods, small vertebrates, and fruit. Most interesting is their breed ing behavior: th e femal e (sometimes with help from the male ) seals herself into the nest cavi ty, w h ere she r emai n s thr oughout inettbation and much of the neslling period, receiving all of her rood from her male through a narrow slit in the mud-sealed entrance. During thi s time fe m a les of m.m y species un d ergo a rapid molt.1nd are flightless. The Rhi noceros Hornbi/1, one of the cies, inhabiLS Mala) tSia ancl tnd onesia. In this photo, a male brings food to a femal e in th e nest cavi ty. Photo b y M. S t range/VIREO. Figure 1-83. P.1puan Frogmouth : Fot md in fo rest s of th e Oriental and Australasian regions t h e frogmouths resemble t heir smaller niglujar relatives in both c r yptic appear.mce and behavior. They have mottled g ray or brown plumage and heav y bills with an enormously wide gape. From an exposed perch the y wait for s u itable prey-large insects or o ther arthropods, f rogs, o r /izards-4o appear. and then swoop down to s natch them from the ground o r bran c hes with their wide IJlll s If distu rbed during the day, the no c turnal frogmouths assume a cryptic pose freezing with the neck ou t s tretch ed and bill angled upward resembling a broken branch. Here a PCJpuan Frogmout h shows its large night-adapted eyes and its wide gape. It inh aiJits northeastem Australia and New Guinea, and islands in between. Pholll by W PeckoverNIREO.

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1 Figu r e 1-84. Varied Sittellas: Because the Australasian region has been isolated from other land masses for so long; many of its birds are unrelated to those in other regions. Through convergent evolution however, many have come to re..
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Chapter 1-lntroductiort: The World of Birds (logrunners), Poma to stomidae ( pseudo-babblers), Corcoracidae (White-wi n ged Chough a .nd Apostle bird), Paradisaeidae ( birds-of-paradise), Cracticidae (b ut c h e r birds, Australasia n Magpie, and currawongsl, Ca ll ae ida e {Wattlebirds), Gra ll l nidae ( mudnest bui l d ers), Mel anoc h a r itidae ( berrypeckers and l ongbills), Paramythiidae (Tit Berrypecker and C r ested B e rr ypecker) Prominent n onpasserines in the Australasia n 1 93 av l rauna Tnclude parrots pigeons a n d doves, and kingfi shers (es pecially l n New Gui nea). In addition many songbird families have had extens i ve radiations here, includi ng the birds-of-paradise the whistl ers and allies, the monar ch flycat c hers, th e hon eyeaters, and the Austra l o-Papuan warblers. Compared to temperate areas of Europe and North America, the t empe rat e Australasian h ab i tats havefewersma ll seed-eaters(someparrots fil l thi s ro le) and many more nectar -fee ders many of which ad as po ll ina tors Notably absent from the avifauna are O l d World vu l tures pheasants woodpeckers trogons, cardueli n e finches and embe.rizids Relat ively few Pal earctic m igrants overwi n ter in the regio n-mostl y waders and a scattering of other m any of the Austra l asian species h ave comple x migratory patterns withi n th e region Some of the more spectacu l ar or peculiar b i rds of the region inti ude the ratit e Emu (fig 1-85) and c assowaries (see Fig. 3-44, and Fig. 1 7 in Evolu tion ofBirdsandAvian Flight> ; the c hicken-like m eg apodes, in whi ch the males care for eggs from seve r al fema les in huge, wa r m mounds of decay in g vegetat i on (see F i g. 6-36); t h e strange, f l ightless K a g u (fig. 1-86)-a single species, presumably re l a ted to the cranes and rai ls, which lives o n t h e verge of extinct i on in the forest unde r brush of New Cal edonia, tapping the ground to l ocate its earthworm prey ; the diverse, birds -of-p a radise-unsu r passed for male of Bird Figure 1-85. Emu: At roughly leet !two melersi tal/ the 11ightless Emu is t h e second largest living bird, to the Ostrich. The only member of its family, it has powerful legs with three toes; coarse, loose, drcooping feathers; and IJare blue skin on the face and upper neck, It is common in open ,1reas throughout Aus-tralia, occupying habit.Jts ranging from near desert condition:; to scrub, wood l ands, and alpine pasttlres. It eats a wide variety of foods, including Insects s uch as 8rasshoppers afld caterpillars, iruit$, seeds, grains, !'lowers, and grasses. It has ada peed we/It o living in are,1s, vnereil ma)'<.'ome in conflict with humans by damaging fences
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1 94 Figure 1 K i n g B ircf.of-paradise: The birds-of -p ; t m dise, found mo stly in New Guinea are famous for their spectacular, co l oriu l p/Lunages and displays. In the past the y were hunt e d intensively t o prov ide feathers for European hat s They in habit wet forests at a variet y of Jlti wdes, a nd the numerous species rlitYer significanlfy i n diet, ; ize, .md matin g sys tem. Mates of the K ing Bird-of-pwadise dfspl.1y solitarily imm trees. Photo b y W. PKkoverNIREO. F igure 1-88. Superb L yrebird: Among t h e l ,l tgest of songbirds, the two pheas ant-sized lyrebfrclspecieslive in the r ai n forests oi A u s t ralia. Although they can r u n quick ly, theirflight is lim ited to sltorl dist J nces and gliding. They most hig h in trees that they ascend by jumping from branch tu L y r el>i rd s forilge for insec t s a nd o ther Jrlhmpocls by di!JIIing and scrJt ching in soil and ro ttin g lngs with their strong ((.>et and cJ,l\+'5. Their voices, oft e n used t o mimi c various sounds, mil}' be the most powerful of any songbird. Male l yrebir d s were killed in /;!reilt numb ers Tn the 19Jh centwy for lheir s tunnin s tail plumes. The famil> is lli!med for the two ou t er tail feathe r s of the Superb L yrebird wh i ch, when rilised all( / spr ead as sl1own here, resemble the fram e of a lyre. Male S uperb L yrebir d s displily to femilles from mouncls o n rhe gro und by Jfching the fo"'" '"d and turning s lowing, all tl1e while vocnl dramatically. Drawing by RoiJert G illmor. KevinJ, McGowan ornamentation (Fig. 1-87 ; a lso see Fig. 3-1 0); a nd the b o w e r birds-builders of remarkably compl ex bowers, which they decorate to attract females (see F ig. 6-41 ). Rivaling the p l umage and co nstru c tions of the previous two gro ups are the songs and calls of the lwo species of l y rebirds. Named for their e labor ate, h ar p-shaped tails (Fig. 1-88), these large passerine s are fantasti c mim ics, includin g in their songs m echa nical sounds as well as the s ongs of oth e r birds. The y are r eported to g ive co nvincing imitatio n s of a pas sing fl ock of coc katoos, complete w ith wing noise and doppler effect ( th e dro p in pitc h when cal l s ar ri ve from a r eceding b ird), and also may mimic l ogging tru c k s and chai n saws. Some bird fam ilies are r e pres e nted b y num erous spec ies i n th e region The 181 s pecies of h o neyeate r s for example h a ve div e rsified into n ear l y every h abitat (fig. 1-89). These arborea l r e l atively dull col o red birds hav e mediuml e n gth, c ur ved bills, and busi l y feed o n nectar I nsects, and f ruits, often con gregating at flowering trees. The y are important pollinators, a nd have a di s tin c tiv e brush-tipped tongue that the y mov e in and out up to 10 tim e s p er second, la pp i ng up nectar. Ccmelt Laboraton1 of Omttlwloetl

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Members of a nother large family, the whistle r s are known for thei r explosive, often-beaut iiul songs. These large, r ou nd-headed birds with stout, slightly hooked bills have evo l ved a variety of foraging behav iors-sear ching trunks, bra n c hes, leaves, or the groun d for i nsects. The numerous Australasian robins a r e actually more I ike f l yca t c hers-a 1 thoug h they usually snatc h food from the g r ound -but the o r a nge, pink, or ye llow breasts and dull-colored backs of many of them are r eminisce n t of both New a n d Old World rob ins. Other spec i es-rich fami l ies include t h e fairywren s-cooperative l y breeding wrenlike bir ds with l ong, cocked tails (see Rg. 6-43)-and waxbills estrildid finc hes in cl u ding the well-known cage bird, the Zeb r a Finch. Oth er characte r istic Aus tr alasia n b ird s include the following: p seudo-babbl e rs: noisy, busy, soc ial g round-feeders with a l ong, curved beak and l o ng, towhee-l ike tail cracticids: a distinctive family with s t out, str aight beaks; loud, me lodic calls; and a genera l ist, c r ow-like diet of small vertebrates eggs, inse cts, and fruits I t includes the vor acious, shri kelike butcherbirds named for rl1eir habit of wedg in g prey into a tr ee for k and dismembering it; the l arge, crow-like cur r awongs; a n d the Australasian Magpie-a crow-s i zed, black-and white b i rd tha t is common, widespread and fami l iar because i t has adapted well to open areas w ith trees such as orc h ards, golf courses, gar dens, and oth e r suburba n a reas. mudnest builde rs: two striking, bla c k-and w h i te, robinsized birds named for their l a rge, cup-shaped mud nests. The Magpiel ark i s widespread, ab und ant, and well-known throug hou t open areas in much of Australia (Fig. 1 -90); and the Torrent-lark inhabits fast f low ing streams in the mountainous areas of New Guinea. co r coracids: the l a rge, b l ackbird-l ik e White-wi n ged Chough and smal ler, seed-eat in gApostlebird. Both are cooperat i ve breeders that range over agric ul tura l fields in huge f l ocks when not breeding. Handbook of' Bird BioloBLf 1 Figure 1 89. R ed-collared Myzomela a Hon eyeater: n1e 181 $per;ies of hon eyeaters form the diverse Austra/,1sian family Meliphagidae These active gre garious necrar vary widely in col or,size (fro m assmal1,1s a hummingbird to nearl y as lartJe as a magpie), shape, and lifesryle. In a n adaptive radia t ion nearl y a s impressive as tharofmarsupia l mammals in the same region the y have spread to every habitat thM contilfns flowering rrees and shrubs evolvins into n ectar-feed in g species whose form and hehavlor resemhle birds as diverse as llycatchers, titmice, nuthatches woodpeckers hummingbirds, and jays. Despite theft varie ty, all honeyeaters have a specialized tongue that differs from the tongues of other nectar feeders. The tip of this is divided lengthwise into four sectio n s each with frayed edges that together form a brusfr. like stru cture w i th which th e bird rapidly licks up n ectar. nley also have a specialized digestive system, which allows the easily-d i gestib l e nectar to hypass the stomach and continue straight to the intestines, where it ca n be abso rbed qvickly. A lthouyh honer eaters also m.1y eat insect s ,md fruit their primary lc10d Is nectar. They dre e vtremel y important pollinators of t1owers, ,1/ld man y spe cies are nomadic, congregari n g in large nvmb ers around flowering trees The m a le Red -co llared M y zomela shown here from mountainous regions of New Guinea is hlack with a crimson collar. Photo b y W. Pec koverNIREO.

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1 96 F igure 1-90. Magpie-l arks: The Mag pie-lark of Australia together 1vfth the Torrentl11rk of New Culnca kmn the tamilr Gra/llnfdae c:ommonly known as builders or # mudlarks." Magpie-larks are co mmon in a wide range or open areas tl1roughow much of including farmlands and cit y suburbs. rheir s(rlklng IJ/ack-andwhil e markings loud and sonRS tin eluding duelling between a mated mall! and female) and behavio r render the m one of the best known birds in Australia. forage on the ground For insects, sn 'ears, two or occasionally three brood s may be raised. Tlw head patterns of Magpie-larks differ b y and age. Note how the he11d of the male ( bottom ) cliflers from that olthe female The ;uvenile (top ) hos a pal (crn intermediate bmween those o( it5 pJrents. Drawing b y N \Ill. C usa lrom A Dictionary of Birds, ediuxf b y Bruce Cmnpbe/1 ami Eliza/Jeth L .ack1 p. 335. CopyrTgl1t I 985, Tht> British Omitho/o gisrs' Union /?r!prodtlced wit/1 tho kind permi5sion of the Britis l 1 Omithologists' Union Figure 1-91. R ifleman: The Rifl eman is one of four known s pecies or the family of tiny, .
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Chapter 1-/ntroduction: The World of'Btrds MnleHuia maximus, stood 1 4 feet tall. Being flightless, t hemoas were easy marks for predatory humans, and all have been extinct for more than 200 years (see Ftg. 20 in Evolution of Bi rds and Avian Flig ht), I s l and Distribution I s l a nds, as long as they are adequate in size and have s uit.abl e habitats and food, almost invar i ably s u pport breeding populati ons of land and freshwater birds from the adjacent con tin en t s The more remote the islands, the fewer ki nds of birds t he y support b eca use the chance of stragglers, or "pioneers," reaching them i n sufficient numbers to found colonies decreases with increased distance from the main l and. In general, the species that colonize the more remote is l ands are not necessarily the best flyers, but th e o nes that can bes t adap t to restr i cted cover and food r esources. Some of the weakest f lyers-for example, ralls and gallinules-have been the most suc cessful colonizers whe reas strong f lyers such as swallows have rare l y colonized distant islands. The kinds of birds on islands close to a continent a r e l ittle different from those on the main l and, because tlwy have not been suf ficiently isolated to develop distinctions as separate species T he y dearly belong to the avifau n a of the continent and its zoogeog r a ph i c region. However birds on remote is l ands and archipelagos h ave often, th r ough long isolation, developed distinctions so peculiarthatthey not only have the status of endemic species, but their origins are blurred as well. A classic example is the avifauna oi the Hawa i i a n Islands, which i ncludes 52 endemic species: one goose two ducks, one hawk, two rails, o n e coot, five honeyeaters one crow, one O l d Worl d flycatcher, one Old World warbler five thrushes, and the endemic subfami l y of Hawaiian honeycreepers ( Drepanidinae) containing 32 species. Of Handbook of Bird BioloBt.t 1-97 Figure 1-92. Wat t lebirds: Three species ofwalrlebircls one of which has recenTly becomeexllnct form thefqmilyCaflaeiclae, e ndemic to New Zealand. N.1med for the pair of co lorful fleshy watt le s 1vhich develop from a told of skin at the base of their /Jill, wall/ebirds are darkr:olored forest l1irrls somewhat resem IJ/ing sle nder gtack/es. The mostly black Huiot eliminated b y 191U as a l'esult of overhunting, feather collecting, iUld h,J/;>ilot destruction had orange or ye l low wa/1/es. The bills of male and Huias differed greatly : the female had a long thin downcurved bill with which she probed for lnrv.1e and adults whereas 1he male had a .
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1-98 Figure 1-93. We ka: t ame, flight less rails a bit larger than a crow, Wek-as inhabit the s c rublands and forest edges of New Zealand, foraging on variet y oi foods as well as scavenging amon g kelp on beaches and from garbage bins. Wekas have strong beaks Jnd ieet and can run very fast, but typicall y walk slowly, flicking their tilils. Photo b y D HaddefiiVIREO Kevfnj. McGowan these b irds, at least four honeyeaters, o n e thrush, and nine honeycreepers recen tly have become ex tinct. Som e Hawaiian bird families appear t o h ave originated in the Nea r ctic, and some in the Austra l asian region but the o ri g i n of others remains un known. H awaiian bird s a r e gene rally placed in the Australas i an zoogeograp hi c regi on based on thei r location, but some researchers place I h em Tn oth er r eg i ons or in a separate region w i th other is l ands of the middle and southern Pacific Ocean. Bird spec ies native to islands normally have sma II populations. Sedentary and without predators, many have become fl i g htless and tame ( Fig 1 -93). They are consequently vu I nerable to extinction from human-imposed causes: direct killing, destruction of habitat, and the introduction of dogs cats, rats, goats, and other human symbionts. U n til humans began eliminatin g them dozens (perhaps even hundreds) of species of f l ightless rai l s ex i sted on different i s l ands a r o und the world. Many of t hese are known on l y from fossil or skeleta l specimens, and disap peared as soon as humans colonized their islands. Nine flightless rail s h ave gone exti nct over the past 150 years, and at l east six more are in danger of extinction-all as a result of humans! Distribution of Marine Birds Marine birds or seab irds, a r e directly associated with the ocean, consiste ntly depending upon i t for food. They are generally divided into pelagic and coastal species. Pelagic birds ro am the open ocean, feeding primarily on small animals such as fish, squ id crustacea, and carrio n at the surface or just below ir; they come roland only to nest. Many pelagic birds a r e i n the large order Procellariiformes (tubenosed seabirds), which incl udes a l batrosses; shearwaters, fu l mars, and typ ica l petrels; storm-petrels; and d i ving-petrels. The remaining pelagic groups are the tropicb irds, some penguins, the boobies and gannets, most of the alcids, the sku as and jaegers, the noddies the kittiwakes, Sabine s Gull, and some terns-notably the Sooty Tern. Coastal spe cies p rimarily occupy the shallower waters around oceanic islands or above the continenta l shelf feeding mainly o n fish, crustacea, and mollusks, whi ch they find o n or near beaches and other shorelines. They frequent land -usuall y coastal areas-in the nonbreedingseason as well as for breeding. These incl ude most pengu ins, cormorants, pel i ca ns, frigatebirds gulls, terns, a nd skimmers. Shorebirds, waders, and wate r fowl, many of which depend more heavily on l and for feeding a nd r a rely venture far fmm coasta l areas, are not conside r ed marine b irds. The except i ons a r e e i de r s scote r s and so m e phalaropes, w hi ch are usually grouped with the coasta l seabirds. Many marine birds, espec i ally the pelagic species, are quite l ong-lived. The North ern Ful mar, fo r examp l e o n ce it has survived t o breeding age, lives an average of 44 years. Marine birds also tend to nest colonially, often on isl ands; l ay only one or sometimes two, eggs; Cornell Laboraton1 of OrnitiJOloalf

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Chapter 1-lntrodudion : The World of' Birds Northern Marine Region Tropical MarinP Region Sou them MJrTne R egion and have long i ncubation fledging, and "adolescent" periods many species taking 5 to 10 years to reac h reproductive age-. Like the land a reas, the seas have been divided by biologists into major faunal regions, as fol lows ( F ig. 1-94 ): ( 1 ) N orthern M arine R egion: The frigid waters of the Ardic sout h to about 35 degrees north l atitude. The water t emperature rises rap idly b e twe en 35 and 40 degrees north latitude, an area termed the Subtropical Converg ence of the Northern Hemisphere. Thfs c hang e in water temperature has important eco l ogical consequences that affect bird distribution, as discussed below. (2) S o u thern M arine R egion: The frigid watersaroundAntarctica north to about 35 degrees south latitude. in the Subtropical Convergence of the Southern Hemisphe re, between 35 and 40 degrees south latitude, the water temperature rises rapidly as in the north (3) Tropical M arine R egion: Th e warm equatorial waters between the Subtropical Convergences of both h em isph eres N o rthern M arine R egion This region is characte ri zed bythefamlly Alcidae which includes 24 species of auks, auklets, murres, murrelets, g uillemots and puffins most of which live in the colder waters of the higher latitudes ( Fi g. 1-95). The medium-sized, black-and-white ale ids are excellent swim mers, pursuing the1rfish prey b y f l apping their wings under water, and are well-known for their upright, penguin -like stance The family is almost completely restricted to the Northern Marine region but sev eral species venture south along thecoastof southern California-the Craveri's Murrel et all the way to Mexico, breeding o n islands in the Gulf of Ca li(ornia. Because many more a lcid species are found in the North Pacific than in the North Atlantic the family may have originated there. Other birds of the Northern Marine region include numerous gu'lls and terns both kittiwakes three species of albatross and an Handbook of Bird 1-99 Figure 1-94. Marin e Faunal R egio n s: Like land areas, the seas have been divided by biologists into major faunal regions. The Northern M arine regi o n extends from the cold Arctic waters south to 1he Subtropic,11 Conversence of the North ern Hemisphere at abo ut 35 to 40 degrees north latitude where the water temperature rfses ropidly. The Southern Marin e region extends from the cold AotMctic waters north to the Subtropical Con11ergence of the South erf) Hemisphere at about 3 5 to 40 degrees south latitude. The Tropical Marine region i nc:ludes the warm equa torial se<1s betweefJ the two Subtropical Convergences. Ad.1pted from a drawing l1y Charles L. Ripper.

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'1 Figure 1-9.l. Common Murres : Like other members or the family 1\lcTrlae, the crow-sized bli!ck-and-w/li(e COnJ mon Murres are designed for swimming. 111eir streamlined bodies and feel set back on the body give the m
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Owpter 1 -ltJtroduction: The World of Birds Tropic a l M arine Region T he warm, tropical waters of this r egion are low in plankton, and thus cannot s upport a rich array of the marine anima ls, such as fish squ id, and crust acea, whi ch ultimately depend on plank ton Most fish are found in schoo l s close to l and, and consequently mostdisUn ctive birds of th i s region-tropicbirds, boobies l rigatebi r ds, a n d several species of terns-keep to the inshore waters. Only three albatross species, seve r a l typica l petr e ls and shearwaters, and a num be r of storm-petre l s (Fig 1 -98) f i nd the planktop supply suff i cie n t for them to occupy the open tropical seas. ThetropTcbi r ds, boobies, and frigateb irds (Fig 1 -99) are found on l y i n thi s region. Mos t Trop i cal Marin e birds feed by hovering and plungi ng quickly into the water after prey or skimming pre y from the water's sur face while hover i ng. The region host s notably few gulls. P l ankton and Bird Distributio n The abu n dance of marin e birds in different oceanic regions i s directly related to thesupp lyofpl ankton.As thebaseoftheocean food chain, p l ankton are consumed by n u merous smal l m ar in e a nimals, which a re, i n turn pre y for larger animals, in a chain of co nsum ers that often ends in seabirds. Where plankton a r e plentiful, so, too are fish and seab i rds. Plankton co nsists of microscopic p l ants and anima l s termed phytoplankto n and zoopla n kton, respective ly. J usl l ike terrest r ia l plants, phytoplankton use the sun's energy to conve r t simple inorganic molec ules i nto carbohydrates; an d like t errestrial p l ants, they require a supply of nutrients to survive. Although s un I i g h t i s plentiful i n the open ocean, nutrients are usually very l imited : when organisms die they tend to sink to the ocean bottom, decompos i ng into the i r co mponent nutrie nts ve r y s lowly. The rethey remain for centuries, un less someth i n g happ ens to bring them to the wate r's surface. Coastal areas includi ng the relalive l y shallow waters over the continenta l H atldbook of Bird Biolo9'1 1.J01 Figure 1-97. S n owy S h e a t hbill: N esc,l(le predators h)' running quickly Tl1e Snow y Sheath/Jill is liJUnd in Southetn Argentina and Chi le, the P.1lklunll lsl.w,ls, and the Antarctic Peninsulaa long, thin linger nf Antarctica e '(tending towar(/ So1.1th America Photo by Tom Vezo!VIREO. Figure 1-98. W ilso n's S t ormP e t rel: Found throu ghout most of the world's oceans, thestarling-sized, pelagic stormare among the few bird speUes that lind tl1e low number of plankton and otl1ettiny org;wisms oftlte open oceans o/ the Tropical Mdrine regio n to live on. They fl y low O\er tile l
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1 Fi gure 1 99 Birds of th e Tr o p ica l M a rine R egio n : Tropi cbirds, boobies, and frigatebirds, found only in the Tropical Marine region, ,1reall pelican relatives in the diverse order Pelecan iformes, whose m embers are distinguished by havin g all/our t oes joined by webbing. a. Red bille d Tropi c bird: The tr opicbirds h,we two long, central tail feathers, which render the m unmistakable in flight. With s hort legs set far back on the body trop i cbirds c,1nnot support th e weight of their body on land and usually nest co l onial/yon s t eep cliffs from which they can t,Jkeoff without walking. The 17icker sized ( excludi n g thelongtai/) Red-billed Tropicbird found in most tropical seas a round th e world, plunge-dives into the wa t er from air in search of small fish or s quid. Photo by T. /. UlrichNIR. b. Mask e d B ooby: L arge birds with long narrow wings and torpedo shaped bod ies, th e booiJies cate h fish and squicl by eit h e r plunge-diving or diving fro m the water's surface. Boobies breed in huge colonies on islands, anc l incubate their eggs by placing them under tile webbing of their feet. The pantropica/ Masked Booby eats mainly flying fish. c. Magnificent Fri gate bird: T h e dark eagl e-sized frig,1t ebirds with their long narrow wings c111d deeply forked tail s can both soar and maneuver skillfully i n flight. T h ey rarelysettleon water, as their plumage wets quickly. They frequently harass o th er seabirds, forcing th e m t o drop or dissorge recent l y eate n fis h The frigatebirds then cat ch the dropped item in midair. They also follow schools of tun a or dolphin to grab the flying fis h t hat they scare into th e air, swoop over nesting colonies and snat ch untended chich ( even of their own species), and scave nge items such as jellyfish el?IJs, and baby wrtles from o n or near the water. Frigat ebirds nest col on iall y on islands building flims y stick nests in dense vegetation s u ch ,1s m,mgroves w h ere they can perch, as their small, s h arp l y-clawed feel are inef{(.oct ive for walking or swimming. I n c o c mship males inflate their hright red thro at pouch vib r ate their wings, and rattle their huge hooked bills. Booby and frigMebird photos by Marie Read. Kevin J. McGowan b c Cornell Laborator'l of OmitholoB'I

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Chapter 1-llltroduction : The World of Birds shelf, tend to be rich in nutrients, as some are carried from land to the ocean by rivers and others are brought to the surface b y the action of trdes, waves, winds, and coastal currents (Fig. 1 100) In the Tropical Marine region, the sun heats the upper la yers of water so much that a significant temperature stratification develops with cold, dense water below the warmer, lighter surface layers. This layering, much like a temperature inversion in th e atmosphere is an effective barrier to mixing between the layers: the cold, dense water stays below, as do the associated nutrients. The dramatic l ayering ex plains why the open oceans oftropicallatitudes are so low in plankton and other marine life. In the Northern and Southern Marine regions, layering is less marked and thus nutrients, plankton, and other marine life are more plentiful. The growth of phytoplankton is seasonal, however with a burst of growth in spring-a time when sunlight is more available and just after winter storms have disturbed the water s ufficiently to bring up nutrient s from deep in the seas. A number o( bird species in these region s are migratory, and some shearwaters and move back and forth across the equator to take advantage of spring and summer in both hemispheres. (Birds with this habtt are termed transequatorial migrants.) In certain areas where ocean cu rr ents meet or where deep cur rent s are forced upward by the topography of the sea floor, upwelling of deep water occurs brTnging ab undant nutrients to the surface. One exa mpl e i s the Antarctic Convergence at roughly 60 de-Oec,Jying Organisms on Ocean Floor Ha11dbook of Bird BioloEII 1 Figure 1-100. C oastal Upwelling: When marine organisms die, rhe y u sually sink and deca y \'E!IJ' slowly in th e cold envi ronment of the ocean floor. There, vast amounts of nutrient s, released from th e I decaying organisms, build up over time. In coastal
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1 Figure 1 -101. Plankton and S e abir d Abundan c e i n the South A tlantic: The graph on the left shows the average plankton abundance in the upper 55 yards (50 m ) of water, in thousands or organisms per liter, at different l11titudes in the Atlantic Ocean. On the right the relative abundance of cErtain species of pelagic seabirds is illustrated for three different latitudes Between about 50 and60degreessouth latitude ina region known as the Anta rctic Conv e r gence, cold north-flowins ,1nd warmer southfloi.Ying currents meet, resulting in large scale upwelling of nutrient-rich water from the ocean's depths. The plethora o{ nutrients Sllppo11s tremendous numbers ofplanl.:'lon which support highe r levels of the food chain i ncluding a great di versity and abundance of seabirds. The nutrient -poor water near the equator supports few plankton, .1nd tlws few seabirds, but the num erous, small storm-pe trels find the plimk'ton supply adequate. Pl.lilklon data originally from Hentsch el ( 1933 ) and seabird dara originally from Spiess (1928), Figvre from n1e I i(e o( Birds, 4t h Editi on by joel Carl Welty and LUis Baptista, copyrig ht t9/J8 b)' Saun ders College Publishing reproduced b y permission of rhe pul>lisher. grees south lat i tude a n a rea extremely rich i n seabirds (Fig 1 -101). Other n otab l e upwe l lings occ u r a l ong the western coasts of several co n tinents where currents f l owing toward the equato r from nort h a n d south tend to bend away (rom shore because of the earth's r otat i o n (a p h enome n on cal led the Cor i olis effect), drawing deep, nutrient -rich water upward near the coastline (Fig. 1-102 ). The south-flowi n g Cal i forni a and nor t h-flowing H u mboldt (or Peru) curre nts, a l o n g t h e west coasts of Nort h and South America, respectively create such upwell ings; a l o n g the west coast of Africa, the Canary a n d Ben gue l a curren t s act similarly. A l tho ugh ma n y tropical pe l agic seabirds a r e wor ldwid e i n d istr ibution, the areas of upwe l ling in t r op ical seas create isol ated patc hes of abundant food. Ma n y b i r d species that specia lize on these resources have very limited ranges-fo r examp le, the Peruvian Booby and Humboldt Pen guin of t h e Peruvian coast; and the Jackass Pengui n and several cormorant species of wester n Afr ica. Upwelling also oc c u r s i n the Arabian Sea f r om May to September, owi n g to the act ion of mo nsoon winds on t h e water, wh ich bri ngs a seasonal abunda nce of p l a n kton and marine birds to an area that hosts few bi rds d u r ing t h e rest of t h e year. U n do u b t edly the most famous Ltpwelling s it!:! i s the sou thwest coast of Peru. He r e t he rich wate r s upports a tremendous popu l ation of anchovies < J virtual banquet for millions of seabirds, as well as t h e basis for an extensive fishing industry ( the I %9to 1970 catch was ove r 10 trillion fish). Many of the seabirds nest on offs h ore islands, where, because of t h e ari d co n dit ions, their droppings ( known as guano ) ac cum u late i n massive quan t ities ( F ig 1 -103 ). Dropp ings from these Plankton A bundance Ecrumor Ill-SO' 6(!-7 0 0 11) Pl ; mkton ( nmtl$iJIICis/t ilttr 1 Latlrtlde 3' 5. L ; uitucf e 22" 5, LalittJde 55 $ ..... Seabir d A b undanc e ....... 01h"' birds Com ell Laborator'f of OrnitiJOloet t S t!lmll-\>rwt

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C hapter 1-1 ntroduction: The World of Birds Ocean Current Upwelling Areas "guano birds"-especially t h e Guanay Cormo r ant, Peru vian Booby, a n d Peruvian Pelican-historically r eached depths of more than 300 feet (90 meters), but have been m ined extensively fo r use as fertilizer sin ce at least the days of the Incas. In 1 972, a combination of particu larly stro n g effects of E l N i no ( tr i ggered by atypical atmospher i c conditions, this wa r m south-flowi n g sur face current of Ecuador exte nds sout h ward to flow a l ong the coast of Per u eve r y two to t en years, warmi ng t h e u pper water layers and p r event i ng upwell i ng ) and overfishing caused a n c hovy a n d t hus seabi r d popu l ations t o plummet to arou n d one million b irds, down from a high of 27 m illi on in t h e late 1950s A l though fis h and seabird popu l ations have increased since thefr de cl i ne t hey have not returned to the i r former levels. Now t h at you have a feel for t h e g r eat diversity of b irds i n the world, as well as t h e remarkable similarities from o n e r egion to an other, you may find that paying attention to birds increases your en joyment of travel-whether aro u nd the world or across th e coun try. If you live in Vermont and travel to Uta h for example most birds you encounte r will be q u ite drffere nt. The common, l arge, blue bird at the feeder will no longe r be t h e Blue J ay but the Steller's Jay. T h e juncos instead of be i ng all grny on top, will h ave black caps and rusty b rown sides, being t h e Oregon r ather than the Slate -color ed form. Open any fie l d guide that covers all of North Amerlca and examine the ran ge maps. You will find that many species are restricted to the western part of the continent, some are r estr i cted t o the eastern, and others can be fo u nd all over. Handbook of Bird Biolo,qlj 1 Figure 1 10 2. Major Ocean C u r rents and Areas o f Upwelling: The water in lhe world's oceans circulates continu ally, thepattem> resulti11g from differen tial heating and cooling of water masses In parts of th e globe, combined IVilh tile roJation of the earth 011d th e ac tion nf p ersiste nt In certain areas, the patcernsof currenc:. cause large-scale upwelling of deep water. Upwellings bring abundant nucrient s to the surface and support large butloc;alized seabird populations. In addition to massive up welling ;usc north of AntatcLica between 50 and 60 degrees so uth l a titude (see Fig. 1-101/, upwel/tngs oru:ur along the wes t ern coasts of Africa, the Americas and Australia. curren t s flowing to ward the equator from north and south tend to bend away from shote due to rhe Coria/is effec t drawing deep nvtri ent-ri c h water upward along the co,Jsts. The California and Perv ( Humboldt) ctJrrents off t/1e the Canary and Benguela c urrents nff Alrica, and the West Australian current offAustrafia c reare such upwellings Upwelling a/su occurs in the Arai>Tan Sea from May t o September, duet:otheactlon of winds on th e water. Aclapttd irom Gra hame (198 7)

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1-106 Figure 1-103. Peruvia n Boob y Nest Colon y on B al lestas I s lands, P eru: Along the southwest coasr or Peru, rhe north flowing Peru ( Humboldt) current bends away from shore as it approaches the equator, pulling nulrient-dch w,1ter tn the surface in a massive upwelling. TI1is upwelling supports a huge population of anchovies-a virtual b < mquet for mil lions of seabirds. TI1eseabirds, including the Peruvian Boobies shuwn here, form huge nesting colonies on i slands In the region such as the Ballestas. Their drop pings acc umulate tu great depths in the arid environment and are mined b y Peruvians for use as fertilizer: Photo by Sandy Podulk,J. K evin J. M cGowan The I mportance of Much of this chapter has described the great diversity of birds-di versity in b ills, wings, t ails, feet, and feathers-as well as the divers i ty of taxonomic groups that use an array of behaviors to explo i t near l y every habitat on earth. Birds are just one compon ent of biodiversity-the great wealth of living organisms that occur on earth. As sci entists con t i nue to study natural systems, t h ey are becoming increasingly aware of the importance of eac h component, and of the complex ways these components a r e related to one anothe r The study and preservation of biodiver sity a r e major focuses of contemporary scientists around t he world. T h e ear th's biodiversity, including b i rds, provides direct benefits to humans in s u ch forms as food, c l othing, recreation, and aest h etic ex periences; but biodiver sity i s more than that. Maintai ni n g biodiversity is cru cia l to sustaining the healthy function i ng ecosystems on w h ich all life depe nds. TI1ese ecosystems mainta i n a ba l ance among orga n isms, p u rify and cycle water recycle nutrients, and ens ur e adequa t e reproduct i on of living t h ings. As you continue through this course try to i nterpret each topic and examp l e in the conl'ext of biodiversity. For exa m p le, ask yourself I n terms of conserving biodivers i ty, why i s i t important to identify and count birds? Why study the s h apes of hummingbir d bills? Why determ i ne the exact m i gration routes of birds?" Bi r ds are beaut i fu l fascinating and intrig ui ng. Having chose n to pu r sue this course you are undouhtedly al r eady d rawn to b irds. But bir ds i n all the i r diverse forms are also v i tal compon ents of the world aro und us, and as you r ead the fo llowing c h apters your respect and apprec i atio n for them will likely grow. Cornell Lcboratort t o('Omitho loeq

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Chapter 1 / ntroduclio11: The World of Birds 1 -107 Appendix A : ORDERS AND FAMILIES OF WOf\LD BIRDS Below are listed the 3 1 orders and al l families of living birds. The list was compile d u sing C l ements (2000) S i b ley and Monroe (1990), and Sibley and Ahlquist ( 1 990) but for North Ameri ca n species follows the 7th ed i t i o n of th e C he c k-li st of North A m erica n Birds (1998) prepa red b y th e Committee on Classificatio n and Nomenclature of the American Ornithologists' Union. Ornithological names are pronounced fo llowing th e rules liste d in a n y standa rd E n g lish diction ary Not e that all order n ames e nd in "-iformes, all famil y names in '-idae, and all $ubfamily names in 11-inae." The n a mes of orders and families are shown in boldface t y p e. Thos e in color a r e represented by species occurring in North America n o rth of M ex ico, or n ea r its coasts, including Hawaii. Th e number of living species in eac h fami l y i s g i ven in p a renth eses; it includes some species th a t have gone extinc t very recentl y. Several orders and families of birds thalretentl y went extinc t are 1 nc1Uded in squ are brackets. With the 7 th edition of the Check-list, the AOU took t h e bold step of making seve r al groups inc ertae seciis, that i s h avi n g "no ce11ain affi nity." Instead of pulling a con f usin g bird somewh e r ejustto give ita home as has been th e general pra ctice i n the past, the committee, in effect, admitted that th ey don' t know where these birds fil in. Futur e studies m ay s h e d more light on the real r e l ationships of these "orpha ned" t axa. nnamiformes nnamidae-llnamous ( 46 ) Rheiforme s Rheidae-Rhea$ ( 2 ) Struthioniformes Struthionidae-Ostrich ( 1 ) Casuariiform es-Cassowaries a nd Emu Dromice idae-Emu ( 1 ) Casuariidae-Cassowar ies ( 3 ) I Aepyornithiforme s ( ext incJJI lAe pyornithidae-E i e phantb1rd s (extin ct ) ] Dinornithiformes I Drnornithidae-Moas ( extinct ) I A pterygidae-Kiw i s (3) Gav iiformes Gavi idae-Loo n s ( 5 ) Podicipediforme s P odicipedidae--Grebes (22 l Sph eniscifo rmes S pheni sci dae-Penguins ( 1 7 ) Proce ltarii f ormes-Aibatrosses, Shearwaters, a nd Petrel s Diomedeidae-Aibatrosses ( 14) Procellarii dae-S h earwa t e rs, Fulmars, a n d Typical P etre l s ( 76) H y drobatid ae-Storm-Pet rels (21 ) P e lecan oidida e-Diving-Petre l s (4) Pel ecanifor m es-Pelicans1 Com1o r,1nts, and Allies Phaeth o ntidae-T r opicbir d s (3) Sulidae-Boobies a nd Gan nets ( 9 ) P elecanidae-P elica n s (Ill Pha l acrocoracidae-Cormor a nts (38 ) A nhingidae--Anhingas ( 4 ) (5) Ciconiiformes-Hero ns, Ibises, Storks, New World Vultures and A l lies Ardeidae-H erons Egrets, and Bitterns (65 ) BalaenicipitidaeS ho ebi ll ( 1 } Scopidae-Ha m e r kop ( 1 ) Threskiornithidae-l bises and Spoonbills (33) Ciconiid ae-Storks ( 19 ) Cathartidae-New World Vullures ( 7 ) Phoenicopteriformes Phoenicopteridae-Fiamingos ( 5 ) Anseriformes--Screamers a nd Waterfowl Anhim id a e-Screamers ( 3 ) Anatidae-Ducks, Geese, and Swan s ( 1 (,I ) FalconHormes--Vu l tures and Diurnal Birds of Prey Sagittariida e-Secretary-blrd ( 1 ) Accipitridae-Kites, Eagles, Hawks O l d World Vulture s a nd Al lies (23 7 ) Falconidae-Caracaras and Falcons ( 64 ) Galli f ormes-Gatlinac eo u s Birds Meg apodiidae-Megapodes (21 ) Cracidae-Curassows, G u ans ant Chacha lac:as (50) Phasianida e-Pheasa nt s Partridges, Grouse Turkeys, Old World Q u ail, a nd Guineafowl ( 1 77 ) O d o ntophoridae-NewWorld Quail (30 ) Gruifo rme s-Cranes, Rails, and All ies Turnicidae-Buttonquai l ( 1 7 ) Rallidae-R ails Gallinules, and Coots ( 144) Heliornithidae-Finfoots ( 3 ) Rhy n oc hetidae-Kagu (1 ) Eury pygidae-S unbitt ern ( 1 ) Me s itornithidae-Mesite s ( 3 ) Aramidae-Limpkin ( 1 ) Gr uid ae-Cranes ( 15 ) PsophiidaeTrump e ter s ( 3 ) of Bird Biolo[jtt I

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I 1'108 Cariamidae-Se r i emas (2) Otididae -Rustarrl!:; (25) Charad r i i formes Shore bird s G ul l$, a nd Auks Burh ini d aC'-Th i ck-knees (9) Charadriidae-Piovers and Allies (66) Haematopodidae--Oyster ca t c h e r s (11) Recurv i rostr id ae--Avocels and St ilt s (1 0 ) Jacanidae--j acanas (8) R ostrat ulidae-Pai nted-Snipes (2) Scolopacidae--Sandpipers aod A l lies ( 88) Dromadidae-Crab Plove r (1) Glareolidae--Co u rsers and PraUncoles ( 17) C hionidid ae-Sheathbi lis (2) Plu viane llid ae-Magellan i c P l over ( 1 ) P e dionomid ae-Piains-wanderer (1) ( 4 \ lbid or h y n chi da e l bisb ill ( I ) L a r i dae-Gulls, T erns Skuas, a nd S k immers ( 1 06) Alcidae-Auks, Murres a nd Puffin s (24 ) famil y INCERTAE SED I S = ''Family with No O r der '' las by AOU; or Pteroclidiformes? o r Charadriffo r mes?j Pteroclidae-Sandgrou se (1 6 ) C:olumbiformes-Pigeon s and Doves I R a phida e-Dodo and So l ita i res (3) extinct] Columbidae-Pi geons a n d Doves ( 314) Psittaciformes Psittacidac -Par rots, Parakeels, L ories, and Macaws (359) Col iifo rmes Coliidae-Mousebirds (t ) Mus o pha giformes Musophagidae-Turaco s ( 23 ) Cuculiformcs Cucu l ida.e-Cu c k oos Roadrunners, and Anis ( 1 42) Opi s th ocom iforme s Opis thocomidae-Hoatzin ( 1 ) Strigiformes-Owl s Tytonidae--Barn Owl s 1 17) St rigidae -Typi cal Owl s 117 0 ) Caprlmu l gifor mes-Oil b irtl a n d Goatsuckers S teatornithidae-Oilbird ( 1 ) Podar gidae-Frogm o uth s (14 ) Aego thelida e Owlet-Nightjars ( 8 } Nyctibiidae-Potoos (7) Caprimu l gidae-Goatsuckers ( 82 ) Apodiformes-Swlf t s ilnd Humm lngbirds H e m iprocnidaeTreeswifts ( 4 ) ( I 01) T r ochili dae--Hummin gbi rds (329 ) Trogoniformes Trogonidae-Trogons !39) Upupiformes Hoopoes and Wood h oopoes Upupidac-Hoopoes 1 2 ) Ph oe ni c ulidae-Woodhoopoes ( 8 ) CoraciiformE.>s-Ki n gf i s h ers anrl A l l i es K,eviu J. McGowan Todid ae-Todies (5) Momotida e-,\1\otmots 19) Alced inidae-K i n gfis h ers (95) Merop id ae-Bee-eat ers (26) Co r aciidae-Rollers ( 1 2 ) Brac h y pteradidae-Gro und R ollers ( 5 1 L e pt oso matid ae-Cuckoo-Roller Il l Buceroti dae-Hornbil l s (55) Bucorvidae-Ground-Hornbi lls ( 2 ) Pici for mes-Woodpeckers a n d All ies Buc conidae-Puffbirds ( 33 ) Galbulidae-jacamars (18) l ndic aloridae-Honeyguides ( 17 ) Mega l a imida e-Asian Barbels (26 ) L y biidae-African Barbels (42) Ramphastidae-Tou cans and New World Barbels (55 ) Picidae-Woodpeckers a nd Allies (21 7) Passer i formes P e r ching o r Passe rin e Birds SuborderTyrann i Suboscines Aca nlhi s ittidae-New Zeala nd W r ens ( 4 ) Pittidae-Pfttas (3 I ) Eury l a imidae-Broadbills 1 1 5 ) Philepittidae-AsiUes a nd False Sun birds (4) Furn ariidae-Ovenb i rd; ( 240 ) Dendrocolaptida e--Woodc:reepers 151 ) Thamnophilidae-Antblrds ( 1 97 ) Formicariidae-Antthrushes and A ntp ittas (60) Conop o pha gi dae-Gnateaters (8) Rhino c ryptidae-Tapac ulos (52) Tyrannidae--New World F l ycatc h ers or Tyr a nt Flycatch ers (398) Cotingida e-Coti1igas ( 6 1 ) Phytotomidae-Piantcutt e r s (3) Pipridae-Man akins ( 44) Oxyruncidae-Sharpbill ( l ) Suborde r Passeri Oscines C l i macteridae-Australasian Treecreepe r s (7) Menuridae -Lyrebircls f2) Atricho r nithidae-S c rub blrds ( 2 \ Ptilonorhynchidae Bowerbirds (20\ Malurida e -FaTrywr ens (26) M e l iph agicJaeHoneyeaters Cl81) Warb l ers (68) Eopsa ltr i ida e-Australas1an RobTns ( 44) lr enidae-leat b i rds and Fairy-blueb i rds ( 1 0 ) Aegithinidae-l oras (4) Orthonythid ae-Lo.gru nners ( 2 ) Pomato sto midae-Pseuuo-BabiJiers (5) Laniidae-Shrikes (30) Vireonidae Vireos ( 52 ) Cinclosomatidae-Whipbirds a nd Quai l-t, hrus h es ( 1 5 ) Cortoraci dae-White winged Chough and A p ustleb ir d (2) Pach ycep h a lid ae-Whistlers a nd All ies (58) C orvidae-Crows, Magpies and ) ays 111 5) Conrell Laboratorq of'Orrritlwlo8'1

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Chapter 1 lnt rodt1dion: The World of Birds Paradisaeidae-Birds-of-Paradise (46) Artamidae-Wood swa l lows ('14) C ra c ti ci dae-Butc h erbirds, Austra l as i an Magpie and C urrawongs( 1 0 ) Oriol idae-Oid Wor l d Orio l es (29) Ca mp ephagidae-Cuckoos hr1kes .1nd Mlnlvets 182) Oicruridae-Orongos (24) Monard\idae-Monarch Flyca t c h e r s ( 1 39) Mal a c onotidae-Bush s hrik es an d Allies ( 93 ) Vangidae-Vangas (14) Ca lla ei da e-Wattlebirds (3) Grallinidae-Mudnesl Build e rs (2) Picathartidae-Rockfowl (2) Alaudidae-L arks ( 9 1 ) Hirundinidae-Swallows (91 ) Paridae-Chickadees and Titmice (58) Remizi dae-Ver dins and P e n duli n e Tits ( 1 4) Aegilhalidae-Bushtit a nd Long-I'Jiledlit s 18) S"ittidae-Nuthatc hes a nd Allie s (25) Certhi idae-Creepers (7) TI'Oglodytidae-W r e n s (78) Cinclidae-Dippers (5) Pycnonoti dae-Bul bu l s ( l.lO ) Regulidae-Kinglets (6) Sylviidae-Oi d World Warblers and G n atcatchers {2 91) Muscicapi dae-Oid World Flyc atchers ( 118) Turdidae-Thrus hes ('1 82 ) limaliidae-Babbler s ( 267) Panurida e-Parrotbills ( 20) (3) Cisticolidae-Cisticolas {117 ) Zos teropidae-Wh ite-eyes 1 95 ) Mimidae-Mocki nguirds and Thrashe r s (35) Sturnidat!-St ar l ings (114) Prunelliclae-Accentor s (13) Motacillidae-Wagtails and Pipits (63) Hypoco lid ae-Hypocolius ( 1 ) B ombycillidae-Waxwings (3\ Pti l ()gnnat idae-Sil ky-flycatchers ( 4/ Dulidae-Palm c h at ( 1 ) I 109 Promer o pidae-St.Jgar birds (2! Dicaeidae-F i owerpeckers ( 43l N e ctariniidae-Sunbirds (124) Melanocharitidae-Berrypecke r s an d longbil l s ( 1 0) Paramythiidae-lit Berrypecker and Crested Berrypecke r (2) Peucedramidae-Oiive Wi!r b ler (1) Parulidae-New Wo rld Warb l ers or Wood-Warblers ( 115) Co erebidae-Bananaquit ( I l Thrau pidae-Tanagers (252) Embe r lzidae-Seedeaters, New Wodd Spa rrows and Buntings (323) Cardinalidae-Cardinals and Alli es (44) lderidae-Biackbirds and Ne1 World Orioles (99) Fringlllldae-F i nches and Hawaiian Hone yc reepers Fringillinae, C haffin c hes (3) Carduelinae, F i n c h es (135) Drepanldina e. H awa i ian Honeyueepers {32) Catambl y rhyn c hidae P i ush-capped Finch i 1 ) Passeridae-Ol d World Sparrows (35) Ploceidae-Weavers ( I I 7l Estrild idae-Waxbills and Whydahs ( 159 ) Ha11clbook of' Bird Biologt(

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7-170 Kevltl J McGowan Com elL Laboratont of Ornitholostt

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Chapter 1-1 rrtrod u etion: T h e World of Birds 1 Appendix B: ORDERS AND FAMILIE S OF NORTH AMERICAN BIRDS Below are th e l iving orders a n d fam il ies of birds that occur in North America north of Mexico, or near its coasts, i ncluding Hawaii, as list ed i n the 7th edition of the Check list of North American Birds (1998), p r epa red by the Committee on Classificat ion and Nomencl3tu re of the American Ornith o logi sts' Union I ncluded here are some bird grou ps that are accidental to this area (marked with an A) a n d some t hat have heen i n troduced (marked wit h an 1). B ird groups t h at, withinthisregion,arefoundonlyon Hawaii, a r e m a r ked with a n H. For eac h fa mily (an d some subfa m ilies), t h e number of species known to occur i n this region is given in pa r e n theses; it inclu des some species that have gone extinct very recently. Th e names of orders are shown in boldface type. Endings a n d p r onunciation g u i d elines a r e the same as fo r the worl. d list. Gaviiformes Gaviidae-Loons (5) Podicipediforme s Podicipedidae-Grebes (7) Procellariiforme s Diomedeidae-Ai batrosses (8) P r oce ll a riidae-Sh earwaters, Ful mars, a nd Pelrels (27) Hydrobatidae-Storm-Petre l s (12) Pelecaniformes Phaetho nlidaeTrop i cbirds (3) 5ulidae-Boobies a n d Gannets (5) Pelecanidae-Pelicans (2l Phalacrocorac idae-Cormorants (6) Anhingidae-Anhingas (1) Fregatidae-Frigatebirds (3l Ciconiiforme s Ardeidae-Herons Egrets1 and Bitterns ( 16 ) Threskiornithidae-lbises and Spoonb i ll s (5) Thr eskiornith inae-lbises ( 4 ) Plata l einae-S'poonb i lls (1) Cicon iidae-Storks (2) Cathart idae-New World Vultures (3 l Phoenicopteriformes P h ueni co pteridae-Fiamingos ( 1 ) A Anser iforme s Anatidae-Oucks, Geese, a n d Swans (62) and Allies Anserinae-Geeseand Swans Tadorninae-Shelduck s and Allies Anat inae-True Ducks Falconi forme s Accipitridae-Hawks, Kites, Eagles, and A l lies (30) Pan d ioninae-Osprey ( l l Accipitrinae-Kites, Eagles, and Hawks (29) Falcon idae-Caracaras and fi.llcons ( 1 0 ) Mic rastur i nae-Forest-Fa l cons ( 1 J A Caracarinae-Caracilras ( 1 ) Falconlnae-True Falcons and Laughing Falcons (8) Gallif"Otmes Cracidae-Curassows, G uans, and Chacha lacas (1) Phasian1dae-Pheasanls. Par tridges Grouse Tur keys, Old Wor l d Quail, and Gufneafowl (] 5) P h asianinae-Partridges and P heasants (11) Tetraoninae-Grouse (1 0) MeleagridrnaeTurkeys (1 l Num i din;1e-Guineafowl ( 1 ) I H Odomopho r idae-New World Quail (6) Gruiformes Rallidae-Rails, Gallilwles, and Coots 117) Aramidae-Limpkin (l) Gruidae-Cranes (3) Gru inae-Typical Cranes Charadriiformes Burhinidae-Th[ck knees (1) A Charadri idae-Lapwings and P lovers ( 16) Vane l linae-lapwings A Cha_radriinae-Pi overs Haem a topod i dae-Oyster ca tchers (3) Recurvirostridae-5tilts and Avocets (3) jacanidae-j acanas (1) A Scolopacidae-Sa n dpipers Phalaropes, and AIHes (64) Sco l opacinae-S:Jndripe r s and Allies Phalaropodinae-Phafaropes G l ario l idae-Courser s and Pratincoles (1) A Larldae-Gulls, Terns, Skuas, and S k immers {57) Stercorar iinae-Skuas and )ilegers Lari nae-Gu li s Sterninae-Terns Rynchopinae-Skimmers Alcidae-Auks, Murres, and Puffins (22) Famil y INCERTAE SED I S = "Famil y with N o Orde r Pteroclididae-Sandg1ouse ( 1 ) I H Columbiformes Columbidae-Pigeons and Doves (201 P sittaciformes Psittacidae-Lories Parakeets, Macaws and Parrots (6l Platycerdnae-Australian Parakeets and Rosellas I H a ndbook of B ird I

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I 1 Psittac inaeT y pical Parrots I Arinae-NewWorl d Parakee t s Macaws, and Parrot s Cuculiformes Roadrunners and An is ( m Cuc ulin ae-Oid World Cuckoos ( 2 ) A Coccyzinae-New World Cuc koos (3) Neomorrhinae-Cround-Cuckoos and Roadrunners (1) Crotophaginae-Anis (2) Strigiformes T y tonirla e-Barn Owl s ( 1 ) Strigidae-Typical Owls (20 ) Caprimu lgiformes Caprimu l gidae-Goatsu ckers ( 9 ) Chorde ilinae-Nlghthawks Caprimu l ginae-N i ghtjars Apodiformes Apodidae-Swifts (1 0 ) Cypseloidinae-Cypse l o idin e Swifts Chae turinae-Cha. eturine Swiits Apodinae-Apodine Sw ift s Tro c hi l idae-Hummingbirds ( 23) Trochi l inae-Typical Hummingbirds Trogoniformes TrogonTdae-Trogons ( 2 ) Trogoninae-T r ogons Upupiformes Upupidae-Hoopoes (1) A Coraciiformes Alced lnidae-Kingilshers (3) Cerylinae-Typi c al Kingfishers Piciformes Pic i dae Woodpeckers and A llies (25) P icinae-Woodpec kers IYnginae-Wry necks A Passeriformes T yrannidae-Tyrant F l ycatch ers or N e w Worl d Flycatch11rs ( 42 ) ElaeniinaeTytannulets E l aenias and Allies Fluvicoii n ae-Pewees, Emp id onn x Fly c a t che r s and Phoebes Tyranninae-Kingbirds and allies Gen era lNCERTAE SED I S = Genera with No Fa mil)"' Pach yramp hu s Becards 0 ) Tityra Tityras ( 1 ) A Meliphagidae-Honeyeaters (5) H Lani id a e-Shrike s (3) Kevin J. McGowan Vireon idae-Vireos (16) Corvidae-Crows, Jays and Magpie s (21) Fly c atche r s ( 1 ) 11 Alaudidae-Larks ( 2 ) Hirundinidae-Swalluws { 14 ) HirundininaeTyp i cal Swall ows Parldne-Chlckadees and Titmice (11) Remiz:idae Penduline Tits and Verdin (1) Aegit halidae-Lon g-ta il ed Tits and Bushtit ('I ) Sittidae-Nulh at c hes ( 4 ) Sittinae-Nuth atc h e s C e r th i idae-Creepe r s ( 1 1 C e rthiinae-Northern Creepers Troglodyt id ae-Wrens ( 9 ) Cindidae-Dippe r s ( 1 ) Pycnonotidae-Bul buls ( 2 ) 1 Regul1dae-Kinglets (2) Syl v iidae-Oi d World Warblers and Gnatcatch ers (11 ) Syl viina e-Oid Worl d Warblers ( 7 ) Polioptilinae-Gnatca tchers and G natwrens (4) Mus c i capidae -Oid World Flycatche r s ( 6 ) t\ TurdidaeThrushes (32) Timaliidae-Babbl ers and Wre n tit (41 Zost e ropid11e-Wh it e -eyes (1) I H Mfmidae-Moc kfngbirds and Thrashers (12) Sturni dae-Starlings ( 4 ) I Prune llidae-Acce nt o r s ( 1 ) fl Motacil l idae-Wagtails and Pipits 111) Bombyciilldae-Waxwings ( 2 ) Pti l ogonatidae-Silky fl y c at c he r s ( 2 ) Peu cedram idae-Oi ive Warb l er ( 1 ) Paru I idae-N ew World Warblers or Wood-Warbters ( 57 ) Coerebidae-Bananaquil ( 1 ) t \ Thraupidae-Tanagers ( 6 ) Emberiz1dae-Towhees a nd New Worl d Sparrows (61) Cardinal idae-Cardinals and Allies ( 1 3 l lcteridae-B i ackbirds and New World Ori oles ( 25 ) Fringi ll idne-Ffnches and Hawa1ian Honeycreepers (57) Fringil l i nae-Chaffinches ( 2 ) A Cardue linae-Finches (23) H o neycr eepers (32) i-1 Passeridae-Oid World Sparrows ( 2 ) I Ploceidae-Weavers ( 3 ) I Plo celnae-Typic a l Weavers E s trildidae Waxbi ll s and Whydahs ("I 0 ) I l l I ri l di nae-Waxbi I I s Com ell Laboratort( of Omitholnfjlj

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Chapter 1 -Introduction: The World of Birds 1 Appendix C: GEOLOGICAL TIME SCALE To understand the significance of the fossil record of birds and other organisms, it is essential to place them in geo logical time-time that begins with the formation of the earth and continues to the present. Geological time is measured in mil lions, even billions of years-a magnitudedifficultforhumanstocom prehend. T h is enormous span oftime is subdivided into progressively shorter units te rm ed eras periods and epochs. Within the rock layers laid down sequentialry throughout geologica l time, fossilized plants and animals s u cceed one another in a recognizab l e order, which ref l ects the evolution of living organ isms through time. The ages of rock layers and fossils are determined by rad i oactive dati n g techniques. T o read this table in chronologicaJ order, begin at the bottom of the tab l e with the formation of the earth and proceed upward. Modern humans first appear in this sequence approximately 200,000 years ago. Large-scale extinctions of many species termed extinction events have occurred throughout earth s history. A l though the ca u se of each event is not well understood, scientists attr i b ut e the extinctions to either catastrophic events, such as meteorite or asteroid showers, or a major shift in earth s environmental conditions due to volcanism, glaciation, g l oba l climate change, or changes in the salinity or oxygen l evel of the ocean. F i ve major and many lesser extinction events have occurred i n the last 600 m illion years Best known is the K-T event at the Cretaceous Tertiary boundary 65 million years ago which claimed dinosaurs marine reptiles, pterosaurs, and many marine i nvertebrates. However, the most extensive mass extinction in earth's history, the Permian Extinction, occurred at the Permian-Triassic boundary 245 mill ion years ago. At this time 90 to 95 percent of marin e species and many terrestria l species wer e eliminated Adapted from Pough et al., (1999). !Open } Handbook of Bird Biolo[jLI

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1 -114 Kevin J. McGowan Com ell of Ornith olo&Lf

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ERA u 0 u u 0 PERIOD QUATERNARY TERTIARY CRETACEOUS JURASSIC TRIASSIC PERMIAN EPOCH Holoc e ne ( R e c ent) MAJOR EVENTS Rise and expansion of human civilizat i ons. Passerines are the mostd1verse and abundant g roup of modern birds. Human act i vities cau se many birds p a rti cularly island birds, t o go edin ct. Pleistocene 1.7 Pliocene 5.2 Miocene 23 Oligocene 36.6 Eocene 55 Paleocene 65 145 .5 208 Time of repeated c h a n ging sea levels, and widespread e xtinctions claimi n g many birds and large rt)ammal$. Hominid s spread g lobally. Modern human s first appear in the fossil r ecor d a pproxima tel y 200,00 0 y ear s agp. Most m o dern species of birds evo l ve. Lwwer latitudes remain warm, while higher l atitudes coo l further MCiluntain building in western North and South America; Panamanian land br idge forms. Sea level drops. Ex tens.ive grasslands and deserts develop as forests contract, Hominids ( earl y humans ) firs t appear. Birds tea c h th e ir m a ximum s peci es divers ity. Climate continues to dry and cool. The Alps a n d Himalayas form, and g rassl ands dominate the pla i n s of Asia and N America. Passe rines diversify explosivel y a nd s pre ad to n e w niches. Modern bird ge ne r a b egin to a ppe ar. Clima.te begin s to dr y and cool, espec i ally at poles; g r eat forests spread to cover most l and masses. Order Passeriformes evo lves late E ocene to early Oli g o c e ne. N e arl y all fam ilies of nonpa sse rines are pre sent.. Global c limate mild and humld. N. America and Europe separate. Mammals diversify. Epoc h of greatest di versifica tion of birds: m ost modern or d er s are present b y 50 m y a,an d most modern families are present by beginning of next epoch. S h orebirds, flamingo-like birds, rail-like birds, and crane like b irds are diver se and abundant. Mil d climate worldw i de. Shallow conti n ental s eas disappear. First primitive pr i mat es. Uth orn i thids ( medium-si zed, flyin g bir ds possib l y ancestra l to ratites) appear inN. Hemi s phere. Giant flightless, predato r y birds appear: Oiatryma inN. H emisphere and phorus r h acids in 5 America Many modern o rder s of birds begin to appear. t Warm tropical and subtropica l climate; slig ht coo ling at end of pe riod. Gondwana l and fragments and most of world is covered by s h a l low seas. Flowering pl ants (angio s p e rms) appear and soon b ecome the dominan t land plants Marine reptil es such as p l esiosaurs flourish in the shallow seas. Dinosaur s domina te th e land, while s m all mammals, pt e r o s auu, and mediums i zed birds dive r sify. The dominant birds are th e enantiorn ithin es ( opposit e birds ) D r o m aeosaurs appear. 'Birds pr.esent i n c l ude t h e toothed birds Hesper ornis and lchthyarnis; and t he earlies t toothless bird, Confvdusornis (12 5 mya). A mass extin ction at t h e end of the p erio d claims dinosaurs pter osaurs mar i n e r eptile s, and many m ari ne invert e br ates. Pangea sp lits into Laurasia and GondWiln a l a n d AtlanticOcea n forms from rifts in the con tinenta l crust. Climate warms worldwide. Lush vegetation domi n ated by gymn osperms. Dinosaurs dive r sify while mammal s r emain small. The first birds,lizari:ls, a nd sa l amanders appear. Archaeopteryx fossils appear 150 my a. :;, MASS EXTINCTIONS Pangea i s elevated and shallow seas d r ain. E xtensive deserts. The land anima l s that su r vived the Permia n extinction diversify a nd sp r ead to vacan t niches Thec o donts r eplaGe th erapsids a s the dominant vert e bra tes. B y en d of peri o d dinosa urs, r eptile s; crocodiles; l epi do sa urs (an cestral s nakes and lizard s), fro glike a mphibians, bony f i s h a nd true mamma l oappea r I Cold climate warms througho u t period; widespread aridity. A single world continent Pan gea forms at end of period. Cone beari n g plants (gymnosperms ) r eplacespore-p r od ucin g p l ants Early reptile s a nd mammal-like r e ptil es (t h era psids) diver s ify and dominate the land. Most extens i ve extinct i o n event in earth's history occu r s on both land and i n the sea at t h e period's e n d defin i n the en d of the Paleoz oic Era. Age of Amphibian s Major glaciat i o n in second half of period Coal swamps prevalent I n trop i ca l areas, dominated by spo r e-p r od ucing p l ants such as mossesandferns. Amphibians and fishes divers ify and spread. I nsec t s diversify greatly on land providinga food sourc e that s purred the radiation of t errestria l vertebrates A major evolutionary advance is t h e a mniotic (ter restrial ) egg whi ch f r ees ancestra l reptiles from a d epen.denceon water. First reptil es appea r ; mammal-like rept iles are present by en.d of per i od Age of Fish. Major mount ain building in 1>1. America and Europe. Climat e cooler Oceans dominated by reef-bui l ding organlsrns ( co rals) First forests and amphibians F ishes diverShall ow seas still extensive. Vascular plan ts and. a rthro pods first a ppear o n l and. jawless fish first jawe d f i s h a pp ear. .... -. .. Formation of the eart h Variable climate. First fossil s known from 3.5 billion yea r s

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A Guide to Bird Watchin9 Steph e n W Kres s When you see something new for the first time-a bright green beetle, a startling yellow flower, or a warbler with a golden head and breast-your first question is usually "What is it?" To mak e sense of the bewildering variety of living things, and to think about how they r ela t e to each other, we need names. Using nnmes hel ps us to separate the jumbl e of bird voices a n d fleei n g brownis h b l u r s i nto dis tinct spec ies w i t h habi t s o f th eir own, and opens doors t o the wonders of court ship, nestin g, migriltion, ;llld other aspects of bird biology. The ability to recognize birds also can help effons in bird con servatio n Much of what ornithologists know abo ut bird numbers and distributions, and about how they change i n response t o altemtions in our environment, comes f rom bird watchers w h o r eport s i ghtings In the i r l oca l areas. I n fact there are many o rgan ized conserv ation projects in which birders can part i c i pate (see Ch. 1 0). But l O h e lp scientists follow t r ends in wild bird populations and develop conser vation plans, you must know how to identify bird species. So, one of the iirst steps in becoming a better earth s t eward is to learn the cast of bird characters inhabiting our planet.

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2 Stephe n W. Kress figure 2-1. Using Silhouette In Identify Bird Group s : flfrcls in the same taxonomic group typically have the same body shape a n d propor lions alt hc!ush the) may vaty in size. Silhouette alone nffers many elves toil bircl's itfen t it) :
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Chapter 2 -A Guide to Bird WatchinB 2-3 1: Belted Kin gfis her. 2: Mallard, 3: woodpecker, 4 : quail, 5: mockingbird 6: kingbird 7 : nutiJatch 8: screech-owl 9: Jay, 10: vireo 11 : cardinJI, 12: European Star11ng, 13 : grack l e 14: warbler, 15: dove, 16: finch 1 7 : swallow, 18: kestrel 19: 20: w r en 21: shrike 22: Killdeer, 23: m eadowla rk.

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2 Stephen W Kress How to I dentifLf Birds Novices invariab l y are awed by how quickly an experienced birder ca n differentiate sim i lar-looking birds z ipping overhead or dashing through dense t angles. L earning to ide nti fy birds is act ually .similar to gelling to kno w you r human neighbors. When you move into a new commun ity, at first everyone is a, stranger. But soon you learn to dTstinguish you r neighbors as you unconsciously bui l d a catalog of pertinent deta ils. One neighbor wears Bermuda shorts all summer anoth er emerges onl y for church o n Sunday, a third is always sur rounded by a gagg le of ch il dren. One shuff les a l o n g s lowly, another is always in a hurry. Some jabber consta ntly, others never utter a peep As their habits silhou ettes, sty les of wa l kin g, and ''habitats become more familiar you learn to r ecogn i ze your ne i ghbors in a f l ash--even at a d i stance In a similar manner, paying atte nti on to differences will help you identify your bird neighbors. You can recognize many birds simply by observinglheirs hapes and postures. Rapid assessments of this sort are based on jizz., a bitding term that harkens back to the "general impres sion of size and s h ape'' (G. I. S. $ ) that Brilish observers used during Wodd War II to distinguish between e n emy and friendly aircraft. As an example, in their book Hawks in Flight, Pete Dunne, David Sibley, and Clay Sutton share a tip for using jizz to separate two similarlooking falcons. The y w rite "A Merlin i s to a kestre l what a Harl ey-Davidson is to a scooter.'' Of course, to get to the point at which you ca n identi fy falcons from genera l impressi ons you must look closely at many fal cons of each kind, so a mastery of jfu c an take ye;m to develop. Beginners should start by l earni n g to idenl'ify the genera l groups of birds. These groups s u ch as warbl ers and flycatchers, contain birds whose members al l sha r e certai n similarities. Warblers, for in s t ance, a r e ge n erally small brightly colored birds that glean insects from leaves and t wigs; flycatchers usually perch upright o n exposed branches, making frequent sor ties to captu r e flyi n g insects. Examples of other groups include woodpeckers, which extract insects from tree tru nks and l arge branches, using their tails as props ; kinglets w hi ch hover near branches while picking off tiny i nsec ts; and wrens small energetic, brown birds that dart t hrou g h underbrush with upright tails The differences among g roup s and among species within groups, can be daunting al first but will become clear w i th experience. During the initia l phase of birding, you w ill see rnany birds that you don't r ecognize. As you begin learning what they are focus on the features described in the following sections Remember, though that in most cases several features must be considered together to make a fina l identi ficat ion Remember also t hat the followingsection presents on l y a general ove rview of ident ifi cat i on features. To exploin all t h ere is to know about identifying b i rds would take an entire book, in fact, severa l books Fortunately suc h books exist and many of these field guides are excel l ent. An annotated list appears at the end of this c h apter. Cornell Llboratont of'OmitlwloBil

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Chapter 2 -A Guide to Bird Watchin& Shape A lthough birds in t h e same general grol.lp can vary dramatically in s ize, they usually have the same body shape and proportions For example, doves have chunky bodies, whereas blackbirds are more slender. Having a knowledge of bird shapes and s i lhouettes a llows you to assign birds to the c orrect group (fig 2-1 ). Sometimes shape can even reveal the exact species. Fori nstance, the European Starling and Belted Kl ngfisher can be iden t lfied by theIr s i I houettes a lone. Shape is not infallib l e as an identification clue though, O nce I spotted a ''fat-bodied" bird with a long t ail sitting at the t op of a smoking chimney. Thoughts of rare exotics floated past as I waited for the bird to rnove. When it flushed from its warm perch, it flashed wh1te patches on the wTnga Northern Mocklngbird fluffed up again st the frigid winte r Postures and Flieht P a tterns Similarities of postures and fl i ght patterns can a lso help to place birds in their proper groups. If you watch one common member of the thrush family, the American Robin, s trut across a yard, you' ll see that the bird takes several steps, then adopts an a lert, upright stance with its breast held forward Hermitand Wood thrushes havesimi larpostures. Other birds that strike vertical poses include hawks, f lycatchers, and larks, whereas birds t hat usually perch horizonta ll y includeshrikes crows, and vireos (Fig. 2-2). Ma n y bird groups a lso have charac teristic flight patterns (Fig 2 3 ). Finches exhibit a steep, roller-coaster f l ight ; woodpeckers generall y fly in a pattern of moderate rises and faJ I s Accipiters such as Sharp-shinned Cooper's Hawks, and Northern Goshawks typkally make several wing flaps followed by a glide unlik e buteos such as Red-tailed Hawks whic h are usually seen soaring. Least flycatche r Am e ric,,n Robin Red-tailed Hawk 2 Red-eye d Vire o Ame rican Crow l'osture and flight pattern can some times help to Identify a bird's species. The American Crow f lies with regulati flapping wingbeats whereas the simi lar-looklng Common Raven flaps occasionally and frequently soars like a hawk. SoaringTurkeyVultures look" l ot like hawks, butthey typically hold their wings in a shallow V shape over their backs, w hereas most hawks and eagles hold their wings flat Figure 2-2. Using Posture fo Identify B ird Groups: Posture c an be a clue t o placing a bird in its correct g roup .. Flyc. u c hers, thrus h e s ilnrl hawks usual/)' stand or perch with an upright smnc e Vireos and cr0111S usually perch hori zont ally. Distant p e r ch,.oc/ crows and hawks may look simf/,11; but noting their different posrures may h elp ro cli.stingtiis h rhem. Handbook of Bird Bioloe'l I

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2 Stephen w_ Kress a Finch Accipiter Buteo -----+---America n Crow ---Common R aven ---GliclinB --flapping Com ell La bora of Omitholo[jtj

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Chapter2A Guide to Bird WatahintJ b Red-tailed 1-fawk Bald E ag le Northern H arrier B ehaviors Sometimes a bird's behavior is your best c lue for determ i ni n g its grou p For inst ance, warblers and v i reos have simi lar postures and s h apes, but t h e two groups a r e readily differentiated by behavior Watch t h em feed a nd yo u l l see t hat warbl ers are q u i c k energetic bir ds that consta n tly dart from p l ace to p l ace as they pick tiny insects fro m leaves and branches I n con t rast, vireos ofte n perc h for several minutes in one place, waitin g unti l they see a la r ge insect a n d then t hey dash forward to s n atch Up thei r prey A close view of warb ler and vireo beaks helps t o exp l ai n this beh av ioral d i ffere n ce Warblers have tri m pointed beaks-ideal tools for eatTng insects such as mosq u itoes or ap h ids. Because these p r ey a r e so small, it takes a l o t of them to m ake a meal fora b i rd sowa r ble r sarealwayson themove, Vireos have stouter bea k s with a distinct hook at t h e tip so they ca n s u bdue and hold much large r prey -hen ce their wa i t-and-attack be h avior You can also differentiate the vario u s groups o f ducks by obse r ving their be h av ior. Dabb l i ngduckss u ch as Mal lards and Gadwalls t i p their t ails up to feed in s hallow water ; whereas Canvasbacks, Redh eads, and other divin g d u cks complete l y d i sappear in searc h o f bottom--dwelling f i sh and p l ants. Be h aviors ca n also hel p disti n gu i s h i n d i vidual species. For i n stance, Fox Sparrows sc r atc h the lea( litter looking for spiders and insects ; Song Spar rows pump the i r tails i n fligh t as they dash f r o m one shrub to the n ext. Or, consider Mou rning Doves and Ame r ican K estre ls. T hese two birds are about t h e same size h ave similar silho u ettes and postu res, and pe r ch on t e l ep h o n e lines in open farm cou n try However, k estrels tend t o pump their tails f r equently while perched, and doves do not ( F i g 2-4) Size Once you have assigned a b ird to the correct group by observing its shape, posture. fl ight pattern, a n d behavior, you can use several Handbook of Bird BiolO[jl( Turkey Vulture Black Vulture F i g ure 2-.1. U s in g Flig h t Patte rn s a s Id e n t ification Clues: Many hird groups have diagnostic llight patterns. a : Finch flfg ht is steeply undulating, whereas woodpecker fligh t has more moderate rises a nd falls. Accipiters t ypically fly with sever.1/ Wlngbeats follo wed by a glide unlik ebuteos1 whi c h usual!) soar. Flight pattern also can help to distinguish species: the American Crow has deliberate, flapping wingbeats, tho Common Rave n often a lternates flapping with h;Mklike soaring. b: Head -o n llig ht pro{i/es may give identit y Soaring Turko)' VultL1res resem/)/e hawks, but hold their wings in a shallow V.shape. whereas most hawks and eagles hold their wings out flat. Black Volwres also I)JVe s flallet, more hawk-/ike profile Northern 1-farriers h old their wings in more of a V shape, but their hovering b e havior genet'illly gives .1way the ir identity. Note how the Bald Eagle's profile is evtm more f/,7/than that of a t ypic;a/ hawk, such as the Red tail e d Hawk.

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2 Step he11 W. Kress other clues l o determine its species. One imp ortant consideration i s size. Birders ofte n use i11miliar birds such as American Crows, Amer i ca n Robins, and House Sparrows as r eferences when they are trying 10 determine or describe the size of a new bird they have seen (Fig 2-5). Size com parisons are most usefu l when you see an un known bird s id e-by-side with a reference bird, but with some practice you will be ab l e to r emember the approximate sizes of common birds and use them as compa r isons. For example, a bright, yellow-and -bl ack finch at your feeder cou ld be an American Gol dfinch, Mourning Dove whi ch i s a l ittl e smaller than a H ouse Sparrow or an Even in g Grosbeak, w hi c h has similar colors and patterns but is near l y as large as a robin. A wood pecker the s ize of a crow would be a Pi l eated; Figure 2-4. Distinguishing Birds b y Behavior: Simllar-looldng species may be distinguishable by l>ehavior. For instance, American Kestrels and Mourning OovesareaiJnw 1he same size, have sim ilar silhouettes lack find1 smaller than a sparrow fs probably an American or a Ewning Grosbeaks have simiJ,,r colors and p,lt terns 11111 are almost robin-s / zed. Some times ) 'Ou n eed two reference bird s tn1 comparison. For instance a waxwing I s bigger than a sparrow hut sm,,IJer lh:tn 11 robin. A Blue lay is larger !han a mhm but smaller th.m a cmw. one the size of a sparrow might be a Downy or a Ladder-ba c k ed woodpec k e r Sometimes you can use two reference birds for comparison. For example, waxwings a r e larger than sparrows but slig htly srna llenhan robins. Jays are largerthan robins but sma ller t han crows. Like shape size is also fallible as a bird-identification d ue. Ap parent size ca n be affecte d by lighting conditions and distance, and size may be espec ially h ard to judge in rain o r fog and at dusk or dawn when, in sil houette perched blackb i rds can look likecrowsand crows can look like hawks. Bird s a lso can cha n ge rheir apparenl size. Dur-HnuHe Sparrow American Cole/finch Downy Woodpecker Americ,m Robin Evening Grosbeak Ceclar Waxwing American Cn:nv Com ell L.aborator'l of Omitholoatt

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Chapte r 2-A Guide to Bird Wat chtne ing hot weather b irds rnay hold their feathers tight l y to thei r bodies, whic h makes t hem look smal ler. Conversely, on frigid days they may fluff themselves up to prov ide better insu lat ion, so a c h ickadee might look like a m ockingbird. Also, b irds of the same species sometimes differ in size. Male gulls, turkeys, and pheasants a r e larger t han females, but female hawks, eagles, a n d owls are larger than m a les. And when youn g b irds leave the 11est t hey can be bul kie r than their parents, Exercise soon trims them to adu lt s ize. Comparin[j Features You can sometimes ident ify s pecies of birds by taking a careful loo k at thei r body features, especiall y extremi ties such as beaks, heads, and tail s As a n example, consider the Hai r y and D owny woo dpeckers, two simi la r l ook ing species that often live i n the same wood l ot and frequentl y appear at feeders. A t fir s t g lance, the two species-which have nearl y i dentica l p lumage patterns-l ook hopelessly simi la r The Hai ry Woodpecker fs n ot iceably larger t h a n t h e Downy Woodpecker but what i f yoll see one o( these b irds alone? The key is to note the propo r tions of t he> b ird1s beak relative to its head (Fig. 2-6). O n carefu I i n spection, yo u can see that the H a i ry Woodpecke('s wood-dr i ll ing beak is nearly as l o n g as its head. H oweve r the beak ofthe smaller, bark picking Downy Woodpecker is only as long as the d istance f r om t h e base of it s beak to the back of its eye, or about h alf as long as its head. Thi s may seem like a subt l e disti n ct i o n but it works! O nce yo u are tuned i n to thi s type of propo r tiona l d ifference in sfze and shape, similar species become m uch easi e r to sort out. Other examples abound: t h e nearly ide n tica l Cooper's and Shar p-sh inned hawks can be distjnguished w hen flying overhead because the Cooper's H aw k head protrudes far ahead of its w ings, w hereas the head of the smaller .Sh a rp-shi n ned Hawk barely extends beyond its w ings (fig. 2-7 ) Greater and Lesser scaups l ook s i mila r-the Greater Scaup i s bigger b u t s i ze is hard to judge w hen you're l ooking at b irds h alfway across a lake-so look at the head: the G reater Scaup has a rounded head w hereas the Lesser Scaup's head i s mor e peilked. I bill l ength 2 bill l engths D owny Woodpecker 1 /Jill l engtl1 al)otlt 1 bill length Hairy Woodpec ker Handb ook of Bird Bioloatt 2 Figure 2-6. U sing Bo d y Propor t i o n s to Di s t in g ui s h S imilar S p e t ies: Pay .1tlenlion to lmd y liwures. especiallv heaks heads at>d t,tils, to tell similar species apurt. The Htliry and Downy wvorlpecker. for instance h,wp almn.telllhem apart is to compare I he length o(each be.1k to the length ol it$ he,1d. n1e Down)' Woodpe cker's beak is only ilbout half as long iJs it; head where,15 llw Hairy WoorlpEcker's IJeak is prupotlionall!!ly much longer. ,1/mvst the same leogth as its l1ead.

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Figurt!27. S harpshinn ed Hawk Versus Cooper's H 1wk Flying Overhead: The S harpshi nn ed Hawk and the Cooper's Hat vk are almost idrmtical in ap pearance and their sl.ze rJnges partially overlap; thus, ii YQI.ISeea /onehird flying overhead it can lie diffir:u/tlu idemlty. A good dlstrnguishing characterist i c is the length of the head. The Coope r's IJead protrudes far ahead ofitswings wl1ereas the Sharp-shinned heJd bar ely extends beyond il5 wings. Upper Beak Thruut Patch L ore Crown Strtj>e Stephen W. Kress Field Marks Birds disp l ay a huge variety of pattern s a nd colors, w hich they h ave evolved i n part to recog nize oth er members of thei r own species for mating Forlu nately, bird watche r s can use t h e same feat ures to h e l p distingu ish species For in stance, the three different but similarlooking species of sea ducks known as sea ters are easy to differen tiate by the pattern of w hi te pat c hes on the tops of their heads. Among adult males, the White-win ged Scoter has one w hite patc h und er the eye, the Surf Seate r has whit e patches on th e fore h ead and nape a nd the Bla c k Scoter has an all-b lack head. When identifying an unknown bird, the following features are particularly im portant. You may fin d it usefu l to rev iew t h e pa rt s of a bird illustrated i n F ig.l-3. Head Check w h et h er th e bird's head has a crest (tuft), w hich will n arrow th e list of poss ibl e species dramatically. Also check for a stripe over the eye (eyebrow stripe), a line thro u gh the eye ( eyeline), or a ring ol color aroun d the eye eye ring) ( Fig. 2-8). These field marks can be very Eyel>row Srripe Eye f?ing White-throated Span'Ow Ruby-cm wned Kinglet Figure 2-8. Fi eld Markson the Head : The folla>vins features a( th e head if serve as sood field marks; A stripe over I he eye (eyebrow stripe) a line through the eye leyeline), a strip e in th e midline tJf the head ( crown stripe), a ring of colur around the eye ( eye ring) and a throat patch. Pay atten t ion lo the co lors of the upper and lower beJk, artd th e > uea between the base of the bill andtheeye knowr) as the lore. CornelL Lnboratont of0m1tholofjlf

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Chapter 2-A Guide to Bird Watchin& usefu I. For example, the b l ack eye I ineof a R ed-b reast e d Nuthatch sep arates it from the White-breasted Nuthatch which complet e l y lacks an eyeline (Fig. 2-9). Thi s f i e l d ma rk can actuall}' be more diagnostic than col o r m any fema l e Red-br easted Nuthatches h ave ve r y li g ht breasts, an d in dim light or backlighting the colors can b e difficu l t to see. As a n othe r exa mple, the Ruby-crowned K i n glet has a w h ite eye ring whereas the similar Gol den-crowned Kingl et has a whit e eye brow st ripe. And as o n e more example, Field and C h ipp in g sparrows both h ave rufou s caps and plain g r ay breasts. ButtheChippi ngSparrow has a crisp, black eyeline an d w hi te eyebrow s tripe, w h e reas the F i e l d Sparrow shows a t most a h int of a brown eyeli n e with an indist i nct grayish eye bro w area. Bill Shape and Color Bill s h ape can h e l p to identify both ge n e ral bird groups and indi vidu a l species. Most members of the family that includes blackbirds orioles, and meadow l arks, fo r example, h ave long, pointed beaks. Flycatchers have bea k s that are flattened with a hook o n the e n d, whi c h improves their ability lo grip l arge i n sects; wa rbl ers gene rally have pointed beaks that l ack a h ook; and vireos have beaks intennedi ate between warb l e r s and flycatchers thickened from the sides with a hook for holdin g l a r ge, squirming in sects. Considering individua l species, study the beaks of t h e similar Greate r an d Lesser yell owlegs and yo u ll see that t h e beak of the g reat e r ti lts slig htl y upward whereas the l esser has a sho rter, straight b eak. Beak co lor is most helpful for i denti fy in g individua l spec ies. The yellow lower beak of the Eastern Wood-Pewee disti n guishes it from the Figure 2-9. Use of Field Marks in Bird Identification: Prominent field marks often bird iden t ification. For instan ce. the black eye/inc of th e Recl-l>re,1sted Nuthatch ( / eft) readily distinguishes it frQm tl1e White-breasted Nuthat c h t righl) which completely la c ks an e)teline. Underdifficulllighting conditio n s this field mark c,1n be more diagnostic than the birds co lomtion. Photographs b y Marie Read Recl-bre,1st ecl Nutha t ch White breasted Nuthatch Hand hook of Bird BioloB'I I

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2 Win g Bars Figurl' 2-10. Fidd Marks on the Wing: Check fer wing parches ;mel wing bars. In a (ew qroups most notabl y thli! warblers and vireos wing markings C
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Chapter 2 A Guide to Bird Watcili'l 2 Vesper e r s In towhees j un cos, m eadowlarks, moc k ingbirds and Sparrows, fo r exa mple, the feathers on the outs i de of both sides of the tail a r e white-an espec i ally prominent Ameri can Crow t'ield mark when the bir d f l ies. House a nd Win ter wrens are quite simil a r in both appearance a nd be hav ior, skulk in g in dense vege t ation with their tails pointed up ward. But the short stubby tail of t h e W in ter Wren immediately distinguishes it from the House W r en. At first glance f l yingcrqws a nd r avens look very simi larboth are big, black birds. But pay carefu l auention to the shape of their tai ls and you will be able to distinguish them. C r ows have tafl s that are smoo thl y rounded or s traight across t h e end w h ereas the raven s tilil is "wedge shaped/' coming to a broad polnt In the middl e ( Fig. 2 12). legs NotE' the length and color of the legs two featu res especially use fu l in iden t ifying sho r ebi r ds. gu lls and egrets ( seeCh. 3, Non feathered Areas legs and Feet, fo r examples ) Keep in mind, however, that no matter how bright yellow a Least Sandp ip er's legs are, they will still look brown after i t wa lks in mud! Colors and Plumaae Patterns A l though color i s often useful in bird identifi cation i t a lso can be misleading. A bird's color often varies with t h e a ngle of view, time of day a n d li ghting d i rection The Indigo Bunting presents a dramatic examp le: i n d i rect light this bTrd flashes a bri ll iant indigo glow, but if it i s litfrom behind it appears jet black. Co lor is especially difficul t toseeoverwa ter. Most d ucks havespectacularcolors, bu t they can be d i fficu l ttosee be c ause oi gla r e fromsurroundlngwatt>r. Inst ead look for the dist i nctive dark a n d lightpatlernsofthe irpl umage. The first edition of Roger Tory Peterson's Field Guide to the Birds didn't even show duck colors, a nd i t worked fine for identification As another examp l e puffin beaks displa y a rainbow of brilliant colors that you c a n sometimes use to id e nti fy th e birds, but you must see the b eak in j ust the r i g ht light to enjoy the display. Rather than cou nting on seeing a co l o r f ul beak first learn to recognTze puffins as members of the auk fam il y a group of plump seabirds w i t h bold b l ack-and-wh ite patterning. Each auk species has a sli gh tly different b l ack-and white pattern that help s birders (and probably birds too) recognize itar a dislance ( Fig 2-13).Theshapeof a puffin's beak ver tica ll y broad-is the seco nd clue to its identity. The beak's flashy co l ors Handbook of Bird BioloB' I Common Raven Figure 1-12. Raven V e r s u s Cro w Tail Shape: In flight, ,,n Ameri cm1 Crow Appears similar to a C ommon Raven_ btlt the two spe cies r:' rounded o r suaig/11 at/h e end where a s the r ;wen's t ai l i s

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Figure 2-13. Plumage Pallerns of Alcids : Because of glare, the true col oration uf birds is especially di[(icult t o acctJrately over Willer. hindering the identification of distant, s1-vimming birds such as
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Chapter 2 -A Guide t o Bird WatchinB would otherwise overlook, becausetheyarefar awa>', skulking in dense vegetation, or otherwise h ard to see. Knowing bird songs also h elps in bird-monitoring proje c ts, when it's not p r actical to observe all birds in a n a rea by s i ght. Hearin g a bird tel l s you as dearly as seei n g i t that the species is present, and population estimates based o n counting calls and so ngs are vita l in assessing the heal(h of wild bird popul a tions. Becoming familiar w i th b ird songs usually comes aft e r leilrnin g to recognize species by sight, and it takes a great deal of pract i ce in the fie l d. The best way to begin is to focus on one or two spec ies at a time. Whenever possible track down singing birds to discover their iden tities. Watching a bird sing its song will improve your memory of that song. Anoth er good approach is to accompany a knowledgeable birder who ca n identify the singers-but you stil l shou ld tr y to watch the birds sing, to estab lish the v i sual connection. Li stening to ings ofbird songs ca n also be usefu l and, unlike listening to wild birds you can replay the songs as often as you want. Recording s are most useful however, as reviews for songs you have already heard outdoors. For novice birders, videos of s in ging birds may be more help ful than audio tapes, as they allow you to see and hear a bird at the same lime. In addition, CDROM field guides and birding games a r e now widely availab le, giving you the added advantage of inter active learning whil e seei n g and hearing birds vocalize. Bird so ng s come in a hu ge variety. Winter Wrens for example, have the longest so ng of any North American bird-each so n g includes about40 notes an d can last more than 10 seconds Th e high pitched musical notes ring through the forest in a rapid eve r-chan ging, piccolo-like run.The s in ge r of a song fitting this description, heard i11 a for est i s easy to identify-and it's a good thing1 because thes e mouse -like birds are seldom seen. At the other extreme is the Hens l ow's Sparrow whose song once was described by Roger Tory Peterson as "a feebl e hiccup." Many bird watchers l earn new songs most easily b y associa tin g them with so ngs they already know. So, mastering a few basi c songs wi II g ive you a framework for comparison When you hear a new song, think whether it is sim i l ar to one with which you are already familiar. I s it faster, slower, higher, lower? How do the rhythm and tone differ?The American Robin for example has a clear, musical song con sisting of a string of short phrases delivered as one song, with very short pauses between the phrases. TI1e Scar l e t Tanager though not rel ated to the r obin, has a similar song-the rhythm is almostexact l y the same-but it has a raspier quality. And the Rose-breasted Grosbeak-again no relation-also so und s much like a robin though it strings its phrase s together more closely, and has a whistled tone, like ''a robin with a co l d in a hurry. Rose-breasted Grosbeaks also may utter a very sharp high-pitched peek -it could be mistaken o nl y for a tree squeaking in the windin the middle of the song or between songs. Not only do unrelated birds often sound alike but related bird s can sound very different. In fact members of a single family often produce a diverse array of songs. The 57 species of North American warblers present a good e)(ample. Although none of them actua J i y Handbook of Bird

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2 16 Stephen W. Kress warble, so m e p roduce insect-like buzzes ( B l ue-winged Warbler), so m e trill ( Pine and Worm-eating wa rbl ers). and others sing l oud, rollicking songs ( H ooded and Kentu c ky w
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Cha?ter 2-A Guide to Bird Watchinn l earn to recognize the bird's voice-the speed, duration, pitch and tonal quality of notes (buzzy, whistled, raspy, screechy harsh musical chirpy). SongSparrows1 for example, sing from 5 to 15 different songs, and many individuals sing their own unique songs Even so, you ca n recognize the voice of thes e common songsters quickl y because they start each type of song with the same two or three clear introductory notes Thoreau noted that the people of New Bedford, Massachusetts described the bird's song as maids maids maids hang on yourtea kettle-ett/e-ettle-ett/e-ettle. Whereas the tea-kettle-ettle part is debat able, the two or three maids followed by a variable jumbl e of notes is nearly alw!lys diagnostic. Recognizing patterns ca n help birders distinguish many other songs as well. Brown Thrashers hold the record as the most varied singers in eastern North America: an individual bird can sing 2 ,000 different songs, m any of which m i mic phrases from other b1rds. Still Brown Thrasher songs !Ire easy to recognize once you focus on the pat tern-they usua lly repeat each phrase twice, in couplet fashion, going on and on in a harsh voice and changing phrases continually. But even though patterns are helpful you still must learn tones. For example, other birds also sing in couplets including the Indigo Bunting-whose song is shorter, sweeter, and more emphatic than the t h rasher's and is the same in every rendition that a particu l ar bird sings-and the Yellow-throat e d Warbler, whose song has a mu c h sweeter fiuid quality. All of these birds coul d possibly b e found singing in the same l ocation. As another example ofpattern, consider the vireos. Most of these treetop birds sing similar songs consisting of whistled notes delivered in short phrases-but the quality and pacing of th e songs vary. Red eyed Vireos have a chant i ng, repetitive song often paraphrased as Here I am way up high, over here, look at me, the phrases continuing on and on i n no particu l ar order, with no long pauses Yellow-throated Vireos sing a similar song in a simi l ar phrasing often paraphrased as three-eight, eight-three, three-eight, eight-three and so on, but their song has a raspy quality akin to the burry voice of a S c arlet Tanager Blue headed Vireos also follow the genera l pattern but compared with the Redeyed Vireo's, their song has a more pu re, whistled C{Uality, is often slower, and includes a pause after every twoorthreephrases-all characteristics that give away their identity as they perch hidden In the l eafy canopy of a deciduous forest. Some birds areactua ll yeasierto identify by song than by sight. For instance, song is one of the best ways to distinguish the Alder, Willow, leas1, and Acadian flycatchers. These small birds look so much alike that it's hard to tell them apart even in the hand (Fig. 2 -15). Indeed the birds themselves probably recogni ze members of their own species by song rather than appearance. Although all four have short, harsh emphatic songs they diffe r enough that a little practice will allow you to tell them apart. The song of the Wi II ow Flycatcher has a sharp, abrupt beginning: FITZ-bew. The alder's song a softer beginning: free-BEE-er. The acadian s song is more shrill than the others: PI-zza. And the Least Flycatcher -unl ike the other birds who sing their song 2 -17 ----------------------of Bird

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2 18 Least Flycatcher Stephen W. Kress just once repeals his song over a nd over in a long series: che-BECK. c h e BECK, che-BECK. H a b itat Each species of bird is predictably found in a partin1lar habttat a nd each plant community-a spruce-fir forest, a meadow, a freshwat er marsh-con tains a predictab l e of birds. For example, Swamp Sparr ows and King Rails are usually found in fresh water marshes In a salt marsh, the Swamp would be replaced by a s h arp tailed o r Seaside sparrow, a nd the King Rall by a Clapper Rail. Learn which b ird s to expec t in each habitat and, faced w1th an unfamiliar bird, you'll be able to eliminate from c ons ideration spec ies that usually live in other habitats (Fig. 2-1 6) Acadian Flycatcher As an examp l e knowledge of breeding habitat would help you iden tify thr ee birds mentioned earlier that singsimilartrill edsongs: the Dark-eyed junc o Chipping Sparrow and Swamp Sparrow Their ranges overlap, and Figure 2-1 !i. Empidonax Flycatcher tdentific.lllon b y Song: Some /)/r(/ 5 a r e easie r t o idet)lif y b y s ong tha n b y s i g ht Least Alder, Will ow, a nd Acadian fl y catc h ers (a// of the g enus EmpidonaxJ a r e mo s tl y drab olive in co l or, wit/1 f.lint eye r ings and wit1,g b ars, and .1re notoriousl y diifi culr t o distin guish b y plumage. However. ei!c h has a short, dis tin c tiv e sung thar i s e asy ror b irders t o par a phrase illld recogni z e in the fie/d. especially in the Northeast-al l three may appear in the same region But their habitat preferences differ and taking habi tat into account when you hear a trill c an help you decide which bird you ate hearin g. A slow trlll emanaling from a mass of cat .. a i l s or a wet shrubby area is almost certain l y a Swamp Sparrow. Chipping Sparrows ate more likely to be suburbanl!es favoring lawns, parks, grassy fields, and for est edges. And juncos a r e most common in the interior of con iferous or mixed woods. But be c areful: Chipping Spar r ows and juncos do over l ap in h abita t so yo u'll n eed to cat c h aglimpseto be certain which bird you are h ear i ng. Breeding can also help distinguish the sim il ar-lookin g Northern and Louisiana waterthrushes. Both species nest on the ground, have simi lar, harsh chip notes and true to their names are usually found near water ( Untrue to their names they are warblers not thrus hes. I Nevertheless they are rare l y found together except during n)igr a tion. The Nort hern Warerthrush s ticks to the quiet, slow-moving, or s t agnant waters of woodl a nd bogs or swamps. whereas t h e Loui s iana Walerlhrush lives in wooded r av ines or go rges with st r eams Although having a knowledge of b ird h abitat preferences is o ne of the best ways to sort out which birds you are most I ikely ro encounter, st,lfprises do occur. During sprin g and fall migrations, for examp le, birds often sett l e down when they get tir ed regardless of h abitat. And Cornell L.aborator4 of Omitholoett

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Chapter 2 -A Cuide to 8ird WatchinB loons sometimes Ia nd on wet highway s during r ainstorms, presumab I y mistaking the broad, winding slick surfaces for rivers. (This is a serious mistake-with their small wings and heavy bodies, these birds need a water runway and can't tak e off from land so they 're stuck.) Tired bitterns sometimes l and in grassy backyards; so accustomed are they to hiding amo n g cattails that they still hold their heads in their char ac ter i stic vertica l posture (Fig. 2-1 7). Ranee and Abundance A l though birds can travel fast and often show up in out-of-the way places, each species usuall y stays within a certai n geographic area called its range You can find information about bird r a nges in any North American fiel d g uide; those with maps are easiest to use i n the field. Some maps show both breeding and winter in g ranges and g iv e dates for the arrivi\ 1 of migratory species. Range maps are inva l uablefor determining wh i c h of several s im ilar species might appeM in your region For instance, suppose you are sure that you've seen a titmouse, but you're not sure whic h of the four North American species it may be. Range maps will show you that in most parts of the contine nt you can figure this out by range a lone, because the species sca(cel y overlap ( fig. 2-18) Know i ng the rel ative abundance of the d i fferent species in your area is also h elpfu l. Some species are common, others are rare. Learn the co mmon b irds first the n you' ll be more likel y to spot unusual birds that l ook different C h ecklists showing the relative abunda nce of birds are avail able in many regions. A warning: when using range and abundance as guides, remember that the birds have not seen the maps o r read the books. R anges c hange, and wande rin g individuals occ ur in most species. I n fact your a lert obseNations can help to do c um ent these events, improving our und erstanding of regional nation
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2-20 Stephen W Kress a .Abandoned Field b Mixed forest Figure 2-16. Common Bird s of eommcm Plant Communities: ,Jc;h hire/ species requires il cerliJin co mbinarion of hdbiMI wm {XInents, and plant community s uppon'i a pred i c table ilssmtmen t of By knowing whit::/1 birr/5 t o expet;J ir> each habitat you may be able I.D idemify an 11nfami/1,1r/Jirtl hy tl1epmccss at' e lim i n ation a: Abandoned Field Inhabitants: Field SparNnus e Wren, Red-Lailed 1-tawk, W,lfll lt:r. b : Mi.Yed Deciduous / Coniferous Forest Inhabitants: Whice-Lhroated Cornell L.aboratont of0mitholo9tf

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Chapter2 A Guid e to Bird W atc h intJ 2-21 c Sonoran Desert d. Cattai l M aNh Sparr/:JI, Wimer Wren Northern Goshawk 13/acklhroaled Gre<:>n Warbler: c: Sonoran Desert 8/a(ktllro.ltec/ Sptlr ra1v, Wren 1-/;-Jrtis' 1-/m.vk, Luq'!. W-lrhler. d : Cat/ail Marsh lnflahitants : SIV;Jfl1P S JMrt 'Ow Marsh Wren NQr/hern Harrier; Common Ye/lawt/)ro
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2-22 Figure 2-17. Habitat Surprises: During spring or fa// migration, e!ihaustexl birds may lm1d allY' v/lere, regardless or /Jab it at. A tired An16'rican Bittern landing in a IJac;ky.,rd, will automJtica/1)1 ils /)pica I vertica l pmture if apwoache
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Chapter 2-A Guide to Bird WatchinB into the breed i ng r ange of Field Sparrows, but Field Spar rows h ead fo r t h e southern United States. The r efore, these potentia ll y confusing spec ies are seldom seen togeth e r Fiel d marks such as t h e Tree Sparrow's b l ack c h est spot a n d t h e Field Sparrow's pink bill, will confirm an ident ification. You can profit from the birding experience of others by seeking out local bird checkl ists produced by Audubon Society chapters and other bird clubs, or the staffs of county, state, and national parks and forests, national wTidlife refuges, nature centers, and similnr organizations (see Fig. 2-34). Such checklists tell approximately when each species occurs in an area a n d desc ribe its r e l at i ve abundance; sometimes they provide arr i val and departure dates It's worth studying the list for any a rea fn which you are b irding, whet h er yo u 're a trave ler, a new resident, or a long time reside n t but beginni ng bird watcher. Sortin9 Out Birds The process of bird identi fica I ion beg ins when you note the features-shape, posture, and behavior-th at permi t p lacing a bird i n the correct gro u p. Identi fying the group great l y reduces the number oi pos s i bilities; you n eed only co nsider which members of the gro u p are likel y to be in that habitat at that t i me of year. Then, look for i i e l d ma rks and listen to the bird's song to make your fina l identifi cat i o n W i th atte ntion to these details, yo 1/ll soon be able to identify your bird neighbors as quickly as you do your human nei ghbors ClosinB the Distance Most birds are wary of approaching people; usually they ily off or retreat into dense vegetation. you can close the distance between you and t h e birds with a few tricks (also see Sidebar 1 : At tracting Bird s to Your Yard ). Sitt i n & Quietlq O n e of the best ways to observe birds up close is a l so one of the simplest: just sit quietly in a likel y location until the birds no longer noti ce you-tr y i t for at l east 10 minu tes, b u t preferably half an hou r You'll be p le
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2-24 Stephen W. Kress Stclebar 1 : ATn\AITING B IRDS TO YOUR YARD Podulka If you already en j oy watching and 1dentifyi n g birds you can add a new dimension to yo u r r e l ationship with them b y ent i c i ng them t o visit and n est in your yard. Birds like humans, h ave a few basic needs that, when missing, limit their abil it y to live in an area At a minimum, al l must h ave food, wa ter, cover, and nest s i tes; some also need song perches, foraging perches dust bathing sites, and specia l ized nest materials. l11e simpl est way to attract birds 1s to put out bird feeders. The key is to provide a V
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Chapter 2 -A Guide to Bird Watching Selected R.eferences on AttractinB Birds Feeding Birds H e nd e r son, Carrol l. 199 5 Wild About Birds: The DNR Bird Fee din g Guide Minnesota De p a rtment of Natural Resourc es, 278 pages. I f no t at booksto r es, order from Minnesota's Bookstore: 1 1? Uni versity Ave. St. Paul, MN 55155 ( 800) 657 3757. An excellent, thorough guide to feeding birds. Includes sections on speciiic birds and how tu a t tract them as well as sections that focus on each different type of bird food, on bird feeder types and how to build them and on troubleshooting. The best all rotmd reference to bird fr:.'eding. Dennis John V. 1983 A Comple t e Guide to Bird Feeding. NY: Alfred A. Knopf, 288 pages. Discusses dffferenl types of feed ers, nontraditional foods co offer birds a n d problems at feeders. Gives information on the behavior and identification of feeder birds, and the food preferences of spe cific feeder birds. S t o k e s, Donald and lillian. 1 987. 7he Bird F e eder Book Boston: Little, Brow n and Com pany 90 pages. Gives basic information on feeder types feeder maintenance, prob lems at bird feeders, and bird behavior. Then discusses each common feeder bird in detail, including information on how to identify and attract it, and its behavior at feerlers. landsca pin g Hender son Carrol L. 1967 Land scaping for Wildlife. Min nesota Department of Natural Resources 144 pages. If n ot at bookstores, or der from M innesota's Bookst ore: 117 Univers1ty Ave, St. Paul MN 55155. (800) 657 3757. A comprehensive guide to bring ing wildliie to your yard or a larger piece of/and. Contains everything from landscape plans to tips 011 building brush piles, bird feeders and frog ponds Detailed charts of plants and their use by wildlife. Most applicable to the Midwest and Northeastern United States. Kress1 S tephen W. 1995. The Bird Garden. london: Dorling Kinders l ey Limited, 176 pages. ProducedbytheNationaiAudubon Society. Discusses many ways to attract birds to your/;Jackyard, from bird feeders and neststtuctures to ponds and gardens. For each re gion of the United States, contains a guide to the plants that are most effective in attracting birds. Pr o vidin g W a t e r low Jim. 1 992 "WettingYourWhis tl e rs." Birder's World, j une 1 992 pp. 50-54. A thorougl1 discussion on how co provide Wafer for birds, from bird baths to Rarden pools and ponds. Handbook of Bird B iolofjtt 2-25 Putting Up Nes t Boxe s H ende r s on Carro lL. 1 99 2 W o od w orking fo r Wildlife. Minnesota Department of Natu r a l Resources. 111 pages. If notatbookstores, or der from Minnesota s Bookstore: 1 1 7 University Ave, St. Paul, MN 55155. (800 ) 657 3757. Detailed plans for constru c ting nest boxes shelves 1nd roost boxes as well ;, s information 011 huw to locate and mdilllilin the structures. Sto kes, Donald and lilli a n 1990. The Complete Birdhou s e Book. Bos ton: Lillie, Brown and Company 95 pages. Gives several basic nest-box plans with dimensions and mod Ifications for most cavity nesters In North Amerira. Also incllldes information on bu) ing locating, and maintaining nesl boxes as well as on the nesting behavior of the birds I

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2 -26 Stephen W. Kress tasks of their daily lives. Once you have settled down for quiet obser vation, you may see behaviors you've never noticed before: a Scarlet Tanager gleaning Insects from leaves an Ovenbird pok ing about in the fo r est debri s a Barn Swallow gathering mud for its nest. I f you hilve the patience l'o be c ompletely still birds may move within a few feet of you. One day after photographing a Black Tern nest from her canoe, a friend of mine retreated about three (eel to watch the adu lts return. In less than 10 minutes, one bird came back and sat on the nest. The other member of the pair flew for a little longer then perched on the bow of the c anoe. After that, each t ime my friend returned to trac k the progress of the nest the birds sat on her cnnoe, sometimes even preening. One b ird even perched on her head-the most magical moment of aiL Becom i ng part of the environment for even a few minutes will leave you exh i larated feeling privileged to have witnessed a few specia I moments in the natural worl d ilS an insider. In spr i ng and summer, be sure to carry insect repel lent-swatting bugs will not help you blend Into your surroundings A cushion to sit on also may increase you r comfort. Pishin9 and Squeakin9 When alarmed many land birds give a call to rally nearby birds who may collectivel y chase away a predator such as a snake owl, or cat. T hese alarm calls tend to have a similar sound a sortof" psh."You c an sometimes bring in birds for closer observation by imitating this sound with a techn i que that birders ca ll ' pishing.'' Repeat a syllable I i ke "psh" or "spsh" in a drawn out, hissing exhalation While pishing, try to be very inconspicuous by standing against the trunk of a large tree to break up your silhouette, or crouching down to hide the typica J huma n upri ght shape. Although pishing is most effective during the breeding season when birds are protect i ng their n esting territories and fledglings itmayworkat anytime(butnoton windy days, because the birds can t hear it ) ''Squeaking" is a simllar aurac ting noise p r oduced by kissing your clenched f ist to make a prolonged squeaking sound. Not a ll birds are equally attracted by pishing and squeaking. Skul kers, such as sparrows and Common Yell owthroats fall for it fre quently; treetop birds respond less often. Success generally depends on a bird's breeding condition and l evel of excitement when you first attemptto att ract it. When you do succeed in attracting a bird it usually darts into view, takes one quick look, then d i sappears again. Chick adees and some other birds may g i ve tJ1ei r own alarm calls if they get excited by your pishing and squeaking efforts; these cal l s wlll help to attr a c t addit i onal birds (Fig. 2-20) M obbi n 9 Small birds often mob potential predators swooping and dash ing at t h e intruders to chase them out of thei r territories. Owls, hawks snakes, and even mammalian predators foxes ca t s o r squirrels -Cornell LAboraton1 of'

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Chapte r 2-A to Bird Watching may be m obbed if they are discovered near activ e nests. Commo n mobbers includ e c hickadees, titmice, ,jays, bla c k blrds grack les, and crows and sometimes these birds, which may have overlapping ter ritories durin g the nesti ng season, wi l l co mbin e their effor t s to mob a co mm o n threat (see the mored'eta11ed dfscussi o n of m obbi n g inCh. 6, Anti predato r B e havi o r : W h y do Some Birds Mob Predators?). Owls spa rk the most int ense m o bb ing b e iM viors (Fig. 2-21 ) Screech-O wls a n d Great Horned Owls often prey upon sleepi n g birds, so sm<1ll birds that c hase owls outoitheir territories during the day may be safer at ni g ht. You c;,n use thi s fact to lur e birds T n for close view: s impl y play a r eco r ded scr eech-ow l call a n d watd1 the re< 1ction. The owl's tremb lin g whis tle usuall y attracts small birds, which flock to t h e sound ready to m ob Even a whistled imita tion of a screechowl ca II may rall y a local son gbird co n gregation. Handbook of' B ird BioiO[JI( 2 Figure 2-.20 A(tracting Birds Using Pishing and Squeaking: Sometimes you L,m brlns in birds ti;r close observation 0)' in)itatin g their a i M m t:JIIs, with a technique that birders ,;all pishing .. : repe,uing a S)l/1,1ble like psh or s psh in a dr;w.m-out hissitJg n,eo redmique wooo !Jest for skttfki n g spf.>c-ies, and [s most ef,.ecrive durrns the seasnf!, r\ sq u eaki n g sound, prod uc-ed by your clenched t ls t or rhe hack or your h and, ha s <) similar a trractive cifect on certain bircls. Avid quickly ovem'l m e their selfconsciousness abou t producing these sounc/5 in pu{lfic:!

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2-28 Figure 2 21. American Crows Mob bing a Grea t Horned Owl: Birds often mob potential pr edators, especial/) ii their nests or young /Ire threatened. Owls trig ger the most intense molJL>in g activity Birders can take advantage of this behavior ; try playing a recurdG-'Ci screech-owl call to lure birds in lor 11 dose view, but don' t overdo thi s activity, because it may cause birds to use up energy reserves they could put to b etter use Drawing by Anne Senechal Faust, from The National Audubon So cie t y Handbook for Birders, IJy Stephen W Kress, 1981. Stephen W. Kress You can trigge r an even st ron ger mobbing reaction by p l aying a screech-owl recording in the presence of an owl model. Make a11 owl from papier-mache strips over a balloon (be sure to give it big ye llow eyes), or buy one at a hardware store (they a r e often sold to sca r e birds from gardens, thou gh they are usuall y ineffective at this ) Mount the model in a con spicuous place, turn on the tape recorder, and h ide nearby to watch the reaction. Note the calls given by the mobbing birds a nd how l ong the reaction lasts. Don't overdo this activityremove the owl after about 15 minutes and l et the b irds sense a victory over the owl invader Oth erw ise, you may cause b irds to squander important energy reserves. Sonas One function of bird song i s to alert males of the same species that a breeding territory is occup i ed. A newcomer who begins to sing w i thin an established territory will soon be confronted by the resident male (some females, s uch as cardinals and orioles, a lso sing to repel otherfemales). Persistent singing by the "chal lenger' male i s usually met with a chase from the territory's first ''owner" (see Ch. 7 for more on this topic) YGu can use this chase response to lure seldom-seen birds into view. Play a tape recording of a species' song within its territory and the territoria l male will quickly appear. Even hard-to-see birds that live in treetops or dense tangles may come Into view to challenge a newcomer Commercial record i ngs serve for playba c k especially t hose on COs, which permit you to quickly retr i eve the species you want by simply punching in the location code You can also obtain calls for playback by making your own recordings oftheterritoria l male you are trying to observe. Birds do not recognize their own voices, so a singing male will come to defend his territory against any rival even his own recorded voice! Although an occas ional confrontation w i th a tape recorder prob ably has little effect on a breeding bird you should take care to avoid excess use. Once the bird you are seeking has appeared turn off the recor der and l et the male sing his song without competition Never use tape recordings to attract rare or endangered birds or any bird nesting outside its normal range. Such disturbance to a bird already in precarious circumstances may threaten its breeding success. Thes e same precautions apply to using pish i ng and squeaking, as well as owl calls and models, to attract birds. Com elL Laboratorl.f of OrnitholoB'I

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Chapter 2 -A Guide to Bird Watchitl[j Bird Blinds Bi r d hlinds genera lly used for close ohse r vation a nd photography of nests, but they also a r e grea t to set up near watering places and spec i a l feeding spots such as th e edges of marshes and wetlands (Fig. 2-22 ). Most b i rd s appa r en tl y recognize the human shape by our distinctive two legged ness, so anyth in g that hides the human form, esp ecially the legs, can function as a blind. Even a burlap bag or loose pon c h o draped over your back will hide you r wa ist and legs, but find a comfortab l e tree for a back prop. S u c h simple blinds, however are usually unsatisfactory for long waiting per i ods; your b lind" moves when you do, so you must keep completely still, which gets downrigh t pai nful before too long. You can construct a s i mple blind that allows some freedom of movement by attaching a skirt to a l arge umbrella bound to the top of a sharpe n ed stake. Or use a l ightw eight card tab l e as the roof and frame for your blind-just toss a prest itch ed cover over the top and you're ready to hide. A number of commercia l blinds are a lso avai l ab l e through catalogs and adve rtisem ents in n ature photography and b ird -wa tching magazines. When sett in g up a bli nd n ear a nest, a l ways keep the best interests of the birds in m i nd. If you choose a com mer cial blind, look for one that you can e rect quickly, because prolonged commotion near a nest can cause birds to abandon it. Stay i n the b l ind for long stints ( several hours), and never distu r b t he vegeta t ion n ea r a nest. Overh anging leaves and branches whi ch hide the nest from predators and offe r s h ade to keep the youn g from overheating, are especia ll y important. ViewinB Birds UsinfJ Binoculars Binoculars are a vi rtu a l necessity for locating b irds. I f you don t yet own a pair you'll find information on select i ng and caring for binocul a r s in the next section. For information on adjus tin g a pairofbinocul a r s to work best w i th your eyes see Sidebar 2: How to Calibrate Binocular s For Your Eyes. Meanwh ile, just a note on using them in th e field: Don' t get discouraged. Birds are moving t a r gets, and both skill and pra cttce are needed to find a bird in a binocu l a r's narrmv field. T h e most important tip is: first spot the bird with your unaided eyes and then holding your head still and keeping your eyes on the bird, lift the binoculars to you r eyes and look thr ough them. Avoid (Continued on p. 2J2) of Bird 2 Figure 2-22. A Homemade Bird Blind: To disguise your human shape, sit in a blind Lo observe hirds near a watering area or feeding such as the edge of a wetland; birds will u sually forge/their wariness and approach, allowing close observation Photograph IJy Marie Read.

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2 Stephen W. Kress Sidebar2: HOWTO CALIBRATE BINOCULARS FOR. YOUR. EYES Stephen W Kress Most binocu l ars have a centerfocusing wheel that adjusts the focus of both eyepieces simultaneously and a separate diopt 'er adjustment that allows you to focus one eyepiece independently to m<1ke up for the diff erences in visi on between your left and right eye. To determine the correct diopter adjustment on your binoculars, stand about 30 feet away from a sign-with clear l ettering-make sure that it is i n the middle of the foca l r a nge of you r binocula rs-and fol low these steps: Step 1 Notice thatthe two b i nocular barre l s pivot on a hinge post, all owing the eyepieces to fit your eyes comfortab ly. Facing the sign, spread the barrels as wide as you can. Then, put the binoculars to your eyes and press the bar rels together until the two images converge I nt o one ( If you cannot push the eyepieces close enough together to see through comfortably. reject those binocu lars; the "interpupi l lary distance of that mode l may be too wide to accommodate the narrowness of the space between you r eyes.) The number (angl e ) indicat.ed on the hinge post will always be the same for your eyes, on any pair of binocu lars. Step 2 Turn the center focusing wheel countercl ockwise as far as it w ill go On most binoculars, one of the eyepieces (ustJally the right one ) is marked wlth calibrations and can move independently. This is called lhe diopter adjust. m ent ring. Turn this ring in a counterclockwise direction until it stops. Now both eyepieces should be out of focus. (Please note: some bino culars have a separate knob in the center or another mechanism for diopter adjustments; if so, c-onsult the manufactur e r's instru ctions.) \ Eyepieces 1\ Hinge Post Step 1: Form one image S(ep 2 b : Turn diopter ad just m ent ring count erclockw i se u n til it s tops S tep 2a: Turn center focusing w heel cou nterclockwise unti l it stop> Cornell Laburaturtt of'Ornitholo8'1

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CJ,apter 2 A Guide to Bird Wat chil!t) Step3 Facing the s ign l ift the binoculars into position and coverth eend oF the rightbin oc ul a r barrel. With both eyes open, LL,1rn the ce nt e r focusing wheel unt i l the l et.te rln g co mes i nt o sharp focus. To b e s ur e you have the sharpest possibl e foc us, pass the s h arpest point and t hen back up to fin d it again Ste p 3: Foc u s left eyepiec e with centra l focusing wheel S t ep 4: Foc u s right eyepiece by turning the diopter a dju s t ment rin g S tep 5: Note your diopter adj u s tment ring setting Step4 NO J:)I.V.IPIHG 2 Now cover the lef1 barre l I keep both eyes open) and turn t h e diopter adjust.ment ring cloc k wise lo brin g the lettering lnto focus. B esureto l eavethecenterfoc u s in e x actly the same positio n as befo re. Pass the point of s h arp focus a n d then b ack up to where the l ette rin g is s h ar pest U n cover the left barrel and th(' binocu l a r s shoul d be i n perfect focus and calibrated for your eyes. Step 5 Note the diopter selling because i t ls now adj u s t e d t o your eyes. Thar setting s houltl remain co n s t ant, unless your vis ion changes. Some people put a piece of tape over the diopter adjlist m e nt to prevent it from s h i fting accidentally. O nce t his is set. you need on l y a djust the cent e r w heel to focus b oth eyepieces. Handbook of' BJrd Bl o lo&Lf I

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2 Figure 2-23. Pointing Out th e Loca tion o( 1 Bird to Other Observers : Lise precise descriplioM tatiJet than vagu e directions StM with close l a ndmark s that all the ohservero can see. then narrow the iieldtmri/ you come to the bird. Fr!r example, co descriiJe th e loca!lon of the screech-owl p i cture( / her.;>. you nu ght See the birch tree t/ral has been chewed b} a beaver! Beyond i t and to the right th e re's a broken snag with fun gi o n il. To the dght o{ th, r l is a large mapl e with a double uunk Foflow tire rightmost trvnk up to tle second br11nch o n the right. The screech owl is aiJavt h alfway au t from the trunk on t/ral br,mcl!.,. Stephen W Kress scanni n g wi l dly through the trees. Practice locating s t ationary obJects first-birdhouses, feed ers, f l owe r s tree b r a n ches. Start with l a rge ob jects, then tr y to find progressi vely smaller ones. PointinB Out Birds to Others If you are with a group o f birders a n d someo n e c annot find a bird that you see, describe the l ocation pre cisely. Vagu e dire ctions, s uch as 11lt's in that tree,'' "It's over there ," a nd ' Look where l'rn pointing," are n o h e l p and onl y I n crease the chance that the bird will fly away before others see it.. Here are a fe w tips for describing a bird's loc a tion : ,r : .-. ( Comell i.Qboratorll of Or,itholo9'1

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Chapter 2-A Guide to Bird WatchinB 2-33 Refer to the most obvious landa mark ne a r the bird, then narrow the f i e l d until you come to the bird For example if you spot a hawk in a farm field you mightdescribe its locat i on this way: "See that l arge reel bar n with the white silo? Look over the top of the silo to the fence I on the hillside behind it, Count eight fence posts to the right a nd t h ere s t he hawk s i tting on top of the post. Do yo u see it?" In wooded a reas, tty referring to an unusual-looking tree trunk or othernaturallandmarkin the fore ground to make sure eve ryon e is looking a t the same pla ce. Using the ref e renc e point, s uccessively indicate trees closer to the bird until yo u lead others to your dis cove r y (Fig. 2 23 ) For maxi mum success c hec k often to make ce r tai n your direct i ons are clear At moments of exc i tement, cal mly sharing a bird dis cove ry takes as m u ch sk ill as locating the bird in the first pla ce. For a b ird in a tree, use the clock'' technique to describe its position (Fig 2-2 4 ) Mentall y superimpose an hour hand ontothetr eeand use 11 to point to the bird. Th i s system works especial l y wel l for birds near th e edge of the tree. A bird in the top of the t-ree is a( twe l ve a' clock; a bird halfwa y down the right side is at thre e o'clock. If a bird is not at th e edge, then th e hour designation is o nly the first step in desC r ibing its posit i on. You must give additional po i nters such as "Find two o'clock in the largest sycamore, then move in halfway to the ce nter of the tree.The bird is i n front of the largest branch near a large woodpecker ho le. See it?" Avoid using distance measur e ments, suc h as "20 feet from th e top of the tr ee ' Most people find b 9 3 F igure 2-24 The Clock M ethod for Describing the Location of a B ird: a : Fot a bird in a tree1 mentall y svperil)lpuse a clock face o nt o t h e /ret:, with twelv e o cloc k a t the top and six o clock at the bottom. Then use imaginary hou r h ,md to point to the b jt d ; in this case the bird is a t one o 'clock This works .Vel/ for a bird a/ the edge o( the tree If the bir d is not at the edge, the hour designation must b e s uppl e m e n ted with acldi1ional directions. b: To Use the clock sys t em when birding from a boat, the ima[JiMry clock is oriented wit/Jtwel\ t e o c lock ,11 thebrJw, u'dock at t h e stem. In tiJis Cllse the Ross'S Cull T s a / seven ocfnck. Handbook of Bird Biolo,qtj

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2 I S tephen W 1\res> it d i fficu l t to agree on exact distances. T h e best c h eck on yo u r suc cess i n giving directions is to ask if people see t h e bi r d The clock system also works for spotting b irds f rom a mov i ng vehi cle s u c h as a bus or a boat. For nautica l birding, the clock is o r iented with t h e twelve at t h e bow and the six at the stern (see Fig. 2 24). Call in g out "Ross's Gull
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Chapter 2-A Guidcto Bird Watchi n[J 2-35 .......... / Eyepi!:!u> Diopter J_..----ildjustmen +0 ... Rin!J trlsms ive Object Lens I L f!l I r-1-'-----' f-"'" -t .tCt-rr Li&ht-&atheritl& .......... I 1[1111111/111!11 v \ \ \' Hinge Post To a birder, the li g htgat her i ng cap acity of binocu l ars is nearl y as important as i mage sharpness Onl y a b ri ght i mage r evea l s the subtle nuances of field marks and the f u ll beauty of bird co l ors. Light en t e r s binoculars through th e objective lenses ( Fig 2-25). As mentioned above, the d i a m e ter of these lenses in millimeters is the second number in t h e binocu lars designa tion-so 7x35 b inocu l a r s h ave 35 mm obj ec ti ve l enses. The bigger the objective l e ns. t h e more l ig h t t h at ca n be gat h ered a11d t h e b righte r t h e image. T h e r efo re, 7x50 binocul a r s have the same mag n ificat i on power as a pair of 7x35, but the 7 x 50, wfth their 50 mm objective l e nses, h ave a s i g ni fica nt l y greater light-gat h e rin g abi lity. Just as an owl's la r ge eyes gather s u ffi cient light to pe rmit noc turnal v ision binoculars with l arge o bj ective l enses provide an advantage for bird watchin g in low light, s u c h JS at dawn or dusk o r i n dark fores t ed hab i tats The best measur e of a bi n ocula r's brightness Is the s i ze of the exit pupil, the hol e that the observer i s looking t hrou g h Y o u ca n see the exit pupil by holding your binoc ulars at arm's l e n gth and looki ng into the eye pleces (Fig 2 26). D e p ending o n the b inocu lars the exit pupil may vary in appearance from a dark hol e to a brillian t clear circle.To determine the p upil size, divide t h e size of t h e objective l ens by the m
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2 Ste[Jhen W. Kress 1X35 provides a m uch bri g ht e r image. 5 mm Pupil Bird ers usi ng binocu l a r s on boats wi11 f i nd t h at an exit pupil of at least 5 n1m offers a distinct advantage. When motion causes yo ur binoc ulars to move in all d i rections aroun d your eyes you may exper ience imuge b l ackouts as the exit pupil moves away from you r eye's pupi l. I n bright dayl ight when yo u r eye has a p upil opening of about2 mm, binoc ulars with a 5 mm exit p u pi l prov i de 3 mm of l eeway to adj ust to the movement. lXSO 1. 1 mm Exil Pupil Although binoculars with largerexitpupi l s a r e better f or boat ing and generall y offe r br i ghter images, they do have drawbacks-p r i ncipally the additional size and wei g h t of the objective lenses and the larger ho using necessary to support them. Fortunately, the best bi n ocula r s made today offer r emarkable bri ght ness with moderate weight by using high-q u ality optica l Figure 2-26. Exit Pupil Comparison: A binocular's brightness can l>e judged by the size of its exit pupil: the larger the exit pupil, the brighter t he image. t-lolrf the IJinoculars at arm's length and look into the eyepieces to see tiJe it pupil. To Cillw/Me the size of the exit pupil, divide thl!! oi the objec_'f./ve lens by the magnification number. For example 1 X 35 binoculars h ,wea 5 mm exh pupil, '" hereas 7 X 50 IJinoculars have an exit ofl. 7 mm,providingil brighterim age Drawing by Anne Senechal from The National Audubon Handbook for Birder s. by Stephen W. Kress, 1981. Figure 2-27. Exit Pupil and Optical Quality: Binoculars with poor quality optici!l c:ompvnants Cilfl have poor light gathering ,111ilities despite IMge objective lenses t-Jo/ding the binocu Iars at armis length examine the edge of th e pupil: it should form a com plete brisht circle as in (a) t/ only the center of the exit pupil is bright, as in (b), inferior optics are blocking some of the coun(eracting the advantagE's of large obje c tive lenses. Drawing by Anne Senecl1al Faust, fmm TI1e Naional Audubon Society t-landl)oo k for Birders, by S teph en W. Kress, 1981 g lass and incorporating design improvements. Check the foll owing tahle to determine which exit pupil size meets your needs: hit Pupil S i.ze 2-4 mm 4-Smm OverS mm Appropria t e S ituation s Bright-light situation s ( s uch as open farml a nd mountains, shor e lines) Shaded situ.:ll'ion s (such as forests) Dusk and dawn, boating Binocu l a r s with large objective lenses Ciln have poo r li ght-gat h e ring abilil'ies i f the opt ics are poor. As one test, caref u lly examine the edge of the exi t pupil to see if it forms a comp lete, brfght circle or if it is shad e d in gray, resul ting i n a brlghlcentra l a rea (Fig. 2 27). If o nl y the center of the exit pupil i s bright then infer i o r optics are b l ocking some of the I ight, and the advantages o f the large objective lenses a r e not being realized. Light enter ing the objec tive lens must pass through as many as eight pieces of optical g lass in each barrel. At each g lass sUiface some light is reflected bac kward rather than passing throug h t h e prisms and lenses. The optics of well -made binoculars are coate d with a nonref l ec-a. High Quality Optics b Low Quality Optics Cornt!ll of

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Chapter 2 -A Guide to Bird WatchinB live fil m that helps deliver more than 90 pe r ce nt of the light gathered by the objective lenses. Withoutthis nonreflective coati ng, binoc ulars may l ose up to 60 percent of the lig h t that enters the objective l e nses. Coa t ed optics also are a great a id when you r e looking at backlit sub, j ects Light reflects within uncoated binoc ulars, causing a nn oying glare. (But even with coa ted optics, n eve r look directly at the sun; it could cause permanent eye damage. ) Make sure th e binoculars you purchase have "fully coated" optics. Although most m a nufa c turers coat the exterior lenses, some inexpensive binoculars ma y have un coated internal optics w hi c n wjl] cause a significant loss of light. Field of View 400(ee/ T he term fie l d of v iew refers to the width of the a rea you see whi l e looking throu gh yout binoculars. It Is usually described as the width of the area visib l e a t 1,000 yar ds irom the observer-for examp le, some binoculars show a n area400feet wide at l OOOyards.lf a l l else is equal, binoc ulars with a hi g h e r magnification power wi II h ave a smaller fi e l d of view than those with a lower magnif i cat i on power Sometimes the manufacturer of a p art icular binocul a r mode l expresses th e field of view in degrees If you wish, you can co n vert degrees to feet simp l y by multiplying the nJJmber of degrees by 52 5, thenumberoffeet in 1 degree at 1,000 yards. Thus, a 6-degree f i e l d of view would s how an area 315 feet wide at 1,000 yard s (6 degrees x 52.5 feet/degree= 315 feet ) ( F i g. 2-28) r-t 1.6]' "-.OOOYards I \ I t-27 The wider the fi e ld of view, the easier it is t0locate birds with yo ur binoculars. Wide-ang l e binoculars are especially u seful for beginning bird watchers, because t h e l arger fie l d of view t h ey ptovide makes it easier to find birds-especially i f t h ey are f l ying or s kulking in de nse vegetation. Manuiacturers of ext r a w ide-a n gle binocul a r s e x pa n d the iield of view by increasing the size and number of lenses Tn the blnocu l a r s' ocular system. The additional opt ics increase the cost of the binoculars a n d make them h eavy and bulky. Because producing binoculars that h ave sharp images across their enti r e field of view i s difficult a nd expensive, b e wafe o f l ow-cost, ex tr a wide-angle binoculars. They are probably o nl y s harp in the center oft he field. Mos t ex perienced bTrdwatch ers find thai a standa rd field of view is adequate for most situ atio n s and that investing in extra-wide-angle binoculars is unnecessary. R.esolution Resolution is a fun ction of the quality of the op t ical glass used in the manufacture of binoculars. High" Fig ure 2-28. f ield of View: The field oi view is th( width of the area yov s e e wllil e looking through y our binocul,?rs. It usoally is expressed as the width of the anM visible at 1 000 yards ( which in this examp l e is 400 (eel) Som e times a m;mvii! c lurer gives the field of view In d e grees (in this it is 7.62 degree s). Cwlvett degree.-t o feet h r multipl) ing thll> number of degrees il y 5 2 . :> (1/Jt number of feet in 1 degree at I 000 yards) 8/noc:lll,us. w ith higher magnltlcalion u sually hav e a narrower field of view than t/1ose with lowermnsni(ication. H andbook of Bird Biolo[Jtj I

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2 a . Binoc ular s In Ali gnment b. Binocula rs Out of Alig nment Figure 2-29. Binoc u lar Alignment: To check the alignment of your binoculars try this simple test. L ook at the roof ofa house t/Jro(lgh them, then co ntinuing t o look throu g h the eyepieces, mov e the binoculars about eight inches away (rom yo ur eyes. I f the binoculars .ue in alig nment the should be at the same level in both fields (a). l ftl>e roof/in e appe.1rs offseJ ( b ) the bino culars Me out of alignment. Draw ing IJ)' Anne Senechal from The National Audubon Society 1-/andbook for Birders b y Stephen W. Kress, 1981. Step/1en W. K,ress qual ity optica l glass is extremely expensive, a n d each lens a n d prism must be professionally ground and mounted with expert p r ecis i on. Top-oft he-line binocu lars are f i nely crafted i nstruments Manufactur e r s of lesser prod ucts cut corners thro u gho u t p r oductio n o ft e n by using less expensive g lass and looser quality control. Hig h -priced binoc ulars usually have excellent optics producing tack-shar p c risp images from the cen ter to t h e edge of the f i eld of view You can c heck the cent e r -to -edge resolution of a pai r of bi n ocula r s by focusing t hem o n a map or newspaper tacked to a wall. Stan d back about 25 feet and see if you can read t h e print at bo t h t h e center and edge of the fie l d of view. Al i 9nment Becausebi nocula r s consist oftwosepara te opt ical instruments basically an i ndividual telescop e for each eye-it i s vitally importa n t that t hey stay in proper a l ignment. When binoculars are funct i o n ing properly, both sides focus on the sam e f i e l d of view, but a shar p jolt can easil y throw them outof alrgnment so that the two fie lds no l onge r over lap. Looking through misal ig -ned binoc ulars. your eyes attempt to bring the two views together. If the binoculars are severely misa I i gned, you wi II see a doub l e i mage a n d the s u bject will look blurry ( when bo t h you reyes are open). I n some ways, bi n ocula r s that a r e only slightly o u t of alignment may be more of a prob1em, because your eyes s tr ain to bring the two images together ; this quick l y result s Tn eye fatigue a n d a headache. I nexpensive bino c ulars are more like l y to go out of alignment t han higher pri ced m ode ls. Prisms a n d lenses i n c u t-rate models may be gl ued i n p l acerathert han securel y strapped by metal b rackets. Tem perature changes or slig ht Jars can easily. throw i nexpensive binoc ulars out of alignme nt. And realign i ng b i no c ulars i s not Cl s i mple task. They m ust be taken apart by an experienced technician and recalibrated us ing specia l equ i pme nt. It makes far more sense to invest in good b i noc ulars in t h e first place than to repeatedly replace or repai r inexpensive binoculars each tim e they gel' b u mped in the fie l d. ( A n d b irdi ng can be very tough on optical eq u ip m ent.)Top-quality binoculars are more likely to withstand t h e stress of constant field use a nd, If you treat them with reasonabl e que, should last a I i fetime. To check the alignme n t of your binocu lars, try the simple test shown in Figure 2 29 B inocular Desi911s You'll find three basi c designs i n modern binoculars-Por r o prisrn, reverse Porro pr ism, a n d roof prism ( f ig. 2-30 ) You can easily recognize st
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Chapter 2-A Guide to Bird WatchinB in line-a feature achieved by placing the two prisms in each barrel close together. Roof prism binoculars offer several advantages over Porro prism binoculars. Most roof prism models are compact and l i ght weight, and they prov ide exceHent image resolution without sacrificing brightness or field of v i ew Many of them focus internally by moving lens elements back and forth ins lde the casing to achieve focus, rather than moving the eye piece asse mbly bac k and forth externally as do most Porro prism bino culars. Internal -focus binoculars can be sealed more effectively and tend to be more resistant to moisture and dirt On the other hand,. roof pr ism binoculars are usually muc h more expensive than Porro prism binoculars their depth perception is not as good, and they don ffocus as well on nearby objects unless they've been specially designed or retrofitted to improve their close-focu s ing ability Mini Binoculars Palm-sized binoculars are becoming increasingly popular among birders. More than 40 models are currently available r a nging in pri c e from about $50 to more than $600 They generally use a reverse Porro p rism or roof prism design, and some models deliver quite sharp im ages. They appeal to many people because they are small and light weight but birders with large hands and long fingers may find them uncomfortable to hold. Beware of lower-priced mini binoculars whi c h often have poor light-gathering capacity. Mini binoculars in the upper price range, how ever, are usually finely crafted instruments with excellent optics. Tested to withstand the rigors of temperature extremes and.sudden jolts, they are a good option for bird watchers who are already encumbered b y bulky camera gear, tape-recording equipment aod field guides. 2 39 a. Roof Prism Binoculars b. Porro Prism Binoculars ..... . 4' , . ., Haru1book of Bird Biolo94 Figure 2-30. Binocular Design: ar Roof pris m binoculars have straight barrels. b: Por to pris m binocular s have thei r ey ep i e ces close r together than their o bje c ti v e lenses. I

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I 2 Figure 2-31. Binoc ulars tor Eyeglass Wearers: To lo cate a bird and tOe: us bin oculars qllickl y on It, birders w ho wear eyeglasses should al11v.1ys keep thei r e)eslasscs in place. Eyeglasses may prohibit the full field of vie>v, thou g h by preventing the eyes from being close to the eyepieces. binoculars have rubber eyecups that can be rolled or folded down to minimiz e this problem Stepl1en W. Kress Binoculars for E11eelass Wearers People who wear eyeglasses should a l ways l eave their glasses in p1a.ce when using binocu l ars (You'll never be able to find and focus quickly on a bird i f yo(.J always have to remove your eyeg lasses befo r e looking through your binoculars.) Of course, eyeglasses do get in the way: they prevent your eyes from ge tting as close to the eye pieces as they should to obtain the fulf field of view. Most binocular manufacturers now have rubber eyecups that you can eit her roll or pop down to m i nimize this probl em, but some work better than others ( fig 2-31 ). If you wear eyeglasses, look through several models and see which work best for you. How t o Sho p f o r Bin o culars Once you 've narrowed down your choice of magnification power objective lens size and field of view try the following tests on the array of suitable binocu l ars behind the store counter. Save your final decision r egardi n g price until you've examined what's available. power by holding one above the other. Alternately look through each binocular comparing them for brighl'ness and clarity. Then compare the best binocu lars from you r first selection with a third group-each time c hoosing the binoculars with the best characteristics. Continue this process of elimination until you have thoro ughlyexnmined everything that's available. Holding t he binocu l ars at arm s length c heck the exit pupils t o see if they are blocked a t the edges by gray shadows Nearly all binoculars under $100 hav e a gray border obstructing the exit pupil. Look i nto the objective lenses to make sure that all opti ca l surfaces are coated with an even purple-vio l et or amber hue. Careful l y ex amine the object ive and o cular lenses for scratches. Be sure that a ll the mechan i cal parts move smooth l y and that th e bridge supporting the barre l s does not wobble. Outside the store, check alignment by looking at a rooftop or hori zontal power line. Carefu llyexaminetheprinton a billboardorsign to see if you can read the l ette ring at the edge of the field as well as at the ce nter. Look at the edge oi a backlit s ign or buildi ng to see if it i s fringed wfth a band of bright color. This f ringing indi cates an i nferior optical system that cannot focus I ight of different wavelengt h s to the same point. After narrowing the field to a few chokes, select the highe sl priced binoculars you can afford. Price is often a good measure of crafts man ship and materials. To produce lower-priced binocu l ars, manufacturers have to make compromises with the quality of their products. But even inexpensive binoculars can be good enough to launch your enjoyment of bird watching. You can always ret ire your Comell La.boraton1 ofOrnltltolom

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Chapter 2-A Gtiide: l'o Bird Watchina iirs t pair to backup s tatus or better yet donate th e m to someone else who wi II appreciate them. Many bird observato r ies, clubs, nature cen ters, and schoo l s are happy to receive donat ed binoculars. How to Clean Binoculars Binoculars s houl d be c l eaned fr e qu ently following Lhese sugges ti ons: Thoroughly wipe off meta l parts and li ghtly brush all l enses with a of l e n s-cleaning tTssu e or a soft camelis-ha i r brush to d i slodge pa rt icles of sand and grit. R e m oving this debris keeps you f r o m scratching the lens and its coa tin g during the cleaning process. Hold binocul a r s upside down so t h a t dirt will fall away from the l ens face Fold a piece of lens-cleaning t issue so that it is at least four laye r s th i ck. This p r events oil fro m your fingers from soa:kTn g thro u g h the lens tissue and o n to the l e n s surface. Use a circu lar movem ent to gent l y wipe all lens surfaces. I f there is a film of o i l o n the lens, put a drop of lens cleaner o n the tissue and repei!t the circula r wipin g m ove m e nt. Look for d i rt on all the internal opt ics by h o l d in g the binoculars up to the lig ht and looking into the o bj ec tiv e lenses Never atte mpt to open the binoculars; you can easily disrupt their alignment. Although it s ex p ensive l eave intemal clean in g to the profess i onals. ProtectinB Binoculars Neve r stroll through the wood s swi n ging blnoculars by the strap; banging them o n a tree cou l d throw them comp l e tely out of alig n ment. Always k eep your binoculars around your n ec k in the field. When you h ave to Jump across a ditch, c limb a rocky s l ope, in to a boa t ordoanyotheract ive maneuver always tuck your binoculars inside your jacket or secure th em under your a rm. Never l eaveyourbin oculars o nyourca r seat a quick stop\vi ll sen d them flying a sure way to knock th em o ut of align m e nt. And n ever l eave yo u r binoculars o ut in the ope n i n your car especia l l y on a h ot summer day. If thieves don't fi.nd the m the s un ma y soften the lens coatings, causi n g them to crack and separate f rom the lenses. Keep binoculars und er c ov er as much as possible if it s tart s rai n Ing. Water c a n l ea k into rhe housin g, causi n g internal foggi n g and omyin g in dirt, whi ch ca n stain the inte rnal optics. Rain guards offer some protection dufln g l i g h t rain a nd drizzle but they a r e not ade qu ate protection for h eavy r a in. I f your binocu l ars do fog up on the inside set them i n a wa rm dry place, and they wlll probably dry out in a coupl e of days. Otherwise, fung u s m ay start g rowin g o n o( Bird Bioloatt 2 I

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Fi gure 2-32. Binocula rs Fac e Man y H a zards: lnttepid birdet'S expose their IJinocuiMs to many perils. Binoculars must be ragged enough to withstand ptecipitatiof) salt >pra)l impacr damage from scramblins over rocky anrl in and out of boats, allras/on from dust and sand, and exposure to t'J,'
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2-A Guide to Bird Watchin[j Th e prob l ems of less l ight a n d more v i bration that accompany greater magnification power in bin ocu l ars also apply to spott in g scopes. High powers magnify the air as well as the subject, oflen producing haz:y images or distracting shimmeri n g from h eat vibrat i ons over wa t e r and other flat expanses. With good observation conditions and a steady tripod t h e extra magnification power of a good scope w i II hel p you t o spot birds and distinguish field marks t hat may be impossible to see with binoculars. When you'rescanninga n area with a spotting sco p e however; it's best to start with a low-power eyepiece (or the l owest setting o n a zoom eyep i ece), and then switch to a higher power once you 've l ocated the birds you want to mine closely. Zoom lenses offer the convenience of being ab l e to change mag nifi cation power from 20x to 4Sx or even 60x with a singl e simple adjustn 1 ent. But viewing conditions a r e seldom good enough to go beyond45x-the image ge n erally becomes too dark to see much det'ail as you move toward 60x. The best al l-purpose magnification power is 25x. Th e top spotting scopes are made with "ED1 (Extralow Dis persion) glass or h ave fluorite-coated lenses. The difference in bright ness and image clari t y bel\.veen these special scopes and Identical non-EO or non fluorite scopes made by the same manufacturers is very noticeable, particularly i n difficult, low-light v iewin g conditions. For overall stab i I ity when yo u 're u sing a sporti n g scope a t rip od ca n't be beat. If you don't like the weight or bulk of a tripod, however you can mount a scope o n a modified rifle stock, butdon'luse a more p owerful eyepiece than l Sx o r 2 Oxyou won' t be ab l e tu hold it steady e n oug h Commercially buil t stocks for spotting scopes and telephoto lenses are availab le. A rifle-stock-mounted scope is difficult to share with a group of bird watche r s I f you want to give everyone in your group a good look at a bird, you should use a tripod. But buying a good tr ipod for birding ca n sometimes be more difficult than buying a s cope. Tripods. come in numerous heights and weights
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2 Stephen W Kress Although birders use scopes most often for l ong -distance viewing of birds that live 1n expansive, open habitats, spotting scopes a lso can provide intimate views of small land birds perched at close range. Such scope-aided views frequent l y reveal the intricate beauty of a bird's plum age and a ll ow you to observe behavi or that might ot h erwise go unseen. Even tiny secretive warblers sometimes sit still long enough to v iew w ith a spottin g scope, especially when they're singing on their territories rather than flitting through the forest canopy in search of insects. How to Shop for a SpottinB Scope The best all-around eyepiece for a birding spotting scope is 2Sx. Because of the effects of heat distortion and loss of I ight eyepieces l arger than 45x usually are useless for birding. I deally, the objective lens (the one farthest from your eye) should be at least 60 mm i n diameter to prov i de adequate li ght. Zoom lenses that vary in power from 20x to 45x are ideal for most bird watching. They pe r m i t convenient scanning at low power and then a quick shift t o higher powe r for l ooking at details. But many of the less expensive zoom eyepieces are opt i cally poor. The only good zoom eyepieces I 've seen a r e the ones made b y the top optica I companies for their high-quality scopes. Don1t buy a cheap spotting scope. Inexpensive scopes deliver fuzzy, distorted images. The shortc ut s the manufacturer took to deli ver a low-cost product wi ll o nl y g ive you disappointing field performance and spl itting headaches. Sel ect a rigid tripod with as few leg adjustments as possible. The f lip-l ock design provides a secure mount for your s c ope and a quick way to set the legs on uneven terrain. Binocu l arsarebest for close-up bird1ng. but fordistantbirdssuch as waterfowl and hawks. spott i ng scopes can expand your vision at least three times beyond that of binocu lars. You' ll be amazed what a difference that makes. R.ecordin& Observations a As I discussed at the beginning of thi s chapter, giving a name to a creature you 've encountered in n ature opens a door to exploring the many facets of its I if e. To keep the door open to turn your ephemera l memories of your dally experiences Into a durable record of the natura I wor l d as it existed in a certain place at a certain time you must reco r d your observations. This can be a source of personal pleasure; the notes will help you relive yourfield e xperiences. In an article about keeping f1eld notes, for 1nstance, t h e Lab of Ornitho l ogy's Director of Education Rick Bonney, wrote "My f i e l d notes f r om a tr i p to the Everglades in 1 986 tell me that on March 1 5 at 1 1 :05 A.M., I saw a Snail Klte hunting over the marsh Com ell Laboratortt of Omitholo!:J'I

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behind the Miccosu kee Rest auran t a n e ntr y that immediatel y r e c a ll s the smell of coffee and refri e d beans." But even m ore i mportant your wri tten r eco rds make the b e n efits of you r time in the field availab l e to a ll who h ave r easo n to care abou t the abunda n ce of b i rd s Rick Bonn ey { 1991) also w rote thi s account o f how documen ting w h at you se e ca n h ave s c ientifi c val u e : I r e m e mb e r the m o rnin g well. It was earl y sprin g 198 7 with liftin g fo g and smell of earth. The season's first bird songs h a d lured me out of bed and I was tramping through the stat e forest behind m y hom e looking for earl y migrants. Around 8:00A. M I had just star t ed back toward the house when I heard a strange so ng, one I knew I d heard before but co uldn t place. Slowly I c r ept toward the bird until/ c ould see it silhou etted agai nstth e sky, perched atop a large shrub At firs t I thought it was a n Indigo Bunting singing a weird song, but after a h ar d e r look I realized that the bird was a Blu e G rosbeak a species I knew well from the South but h ad never b efo r e seen in Upstate New York (Fig. 2 3 3). As it turned out, ver y few people had seen it, perhaps only o ne. For no good reason I didn t think t o l ook up the bird's s tatu s right away, but several months l ater I was p e rusing B i rd s of New York State by j o hn Bull and read this: "As far as I am aware, the only Upstate report of a Blue Grosbeak witli details is that of a male observed near L ake C h amplain on June 7 7 7 964." Handbook of Bird Biolo9'1 Figure 2-33. Mal e B l ue G r osbea k : Always keep accura t e field n o tes-you c,lflnever pr e di ct w h e n t h ey mi ght h av e scien tiiic v,1lue, s u c h a s d ocume ntin g the occ urr e nC' o f <1 s p ecies out side it.S n orm a l ran ge Photogr
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2 I Stephen W. Kress Wow! I thought. My Blue Grosbeak had been a really good bird. I shoul d have reported it. I s hould still report it. When had I seen it? Let' s see, it was late April -or was it early May? Already I couldn't remember. And n ot only had I n eg lected to record the date, I h adn't recorded any infor mation about the bird at a/1-so even if I could reconstruct the timing, I had no documentation that would prove to anyone other than myself that a Blue Grosbeak (1ad decided to visit Willseyville New York, in the spring of 7 987. The moral is quite simple: take field notes .... Suc h observatio n s h ave scientific value. My sighting, for example would have been useful to ornit h ologist /
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Chapter 2-A Gt4idtt to Bird Watchiil[i The Edwin B. Foroythe N ational Wildlife Refuge 's Brigan tine ud Barn egat D ivisi ons contain more than 42,000 of sout h ern Now Jersey coastal h a b irat. Refuge head quarteiS and public usc facilitie!, incl u d ing an eig h t-mile Wildlif e Drive, observation towers and IWQ shon n ature trail s, a r e at the Brigantine Division ,Best birdwatchjng opportunities occur duri n g sp r ing and fill migra tions A "Guide to Seasonal Wildlife Activiiy" is avail ab l e in the refuge's general brochure This folder identifies 293 spec ies that have been observed at the Briganti n e and Barnegat Divisions. Names and orde r of listing are in acco r dance with the Si n h A merican O rn itholo gists' U n ion Checklist. Most b i rds are migra t ory. T h eir seasonal occurrence is coded as foUows: SEASO N s Spring S Summer F F>IJ W Winw Matc:h -My June Augwt September November December -February B irds known t o nest on or nar the refuge Ita /in inJ;catt threattnttilmdAngrml tptritt RELATIVE ABUNDANCE a abundanr a species which is very numc.rous c common likdy to be =n or heord in .uitab l e hablc:u. o uncommon present b ut not to be seen o occasiorul sccn only a few tim<$ during a =n rare may be pr<:SCDt bUt not <:Very year seen onJy once or twice on n:fuge LOONSGREBES R.:d-throated Loon ...... ........ .... .. ..... ... . .. ,. . o Loon. .... . ...... .......... .... ... .... .... .. .... o Pied-billed Grebe:. ............................. ............ u HomW Grebt: ... ....... .. ... ...... . . u s 0 S HEARWATERSPELICANS CORMORANTS Sooty Sh""""'' "' ............. ............................. -Northrm Gwncr............. ............................ r AmcriCUl 'Wh it e Pdk:an ....... .. .... . ............ .. r Brown Pd.ian ... . ............. ... .. ......... ........... Great Connon.nt ---... ...... . . ... .. .. .. Doub le-crCSfed COrrn,onnt . ........ ....... ....... u BITTERNS-HERONSIBISE S A.rnerican Bitt ern .. ... ................ ............ ... u 1[: : Grear Egm ,.......... .............................. ....... c Snowy fs"'' ......... . ................................... lit-de Blue Hcwu... ......... ... .... ...................... ti' Trioolorcd Heron ............... ....................... u J1 Egret ........ .... ......... ........ ... ... ............. .. Gtttn -backcd Hemn ....... o j_ B)>elc ... ........... .. .......... .... ...................... "'Whitt"-f.u:td Ibis .... ..... .... ............... .. ...... . .... SWANSGEESE-DUCKS Tundra Swan ................ . ... ........................... u Mute Swan .... .............. . ........ .... . ...... . .. c Greater Wbirc--ffontW. Cocnc ... ................. J_ SnowG oosc .......... _ ., ...... ....................... > -Res.' G<>t>K ... .... ... ........ ............ ..... ............ .. ........... ........ .......... ............ ....... ........... IQQ:t-C.nd Goru< ...... ......... ... ................. ............ c Wood Duck.................................................. u Teal .. .... -. ...... .. ..... ,....... ... c .fL American Black Duck ....... a G Nmthc:m rinuil ,........................................... B lue .. mgcd Teal ...... ........................ .......... c Nonhem Shoveler.. .. .. ...... ..... .. ... .. ..... . c G>ly. checklists can b e meaningftli suuraes of data n n bird disld burion ,md c hanging abundance Don t ju$ 1 check off tire s p ecies; i nclude 11n tJC count o r an estim.1tli' of the numbers IJf birds of all species seen. F;// out the e.'ac r location, number ofhuur s sptnt in the r/eld, and tl1e weat/Jerco nd ltlon>. For accuraC)r' > sake, the inlom1ation should be iil!ed out i n the field. C h ec klist re produced with permission Edwin B. Fat sythc Nati o nal Wilclliti? R o iuse U nir er l States Fis/l and Wilclliie Service. Your compl ete daily c h ec klists may b e useftl in preparing and updating l ocal a nd region a I c he ck l islS, and t h ei r va li.Je over time because they are an impor tant source of baseline data for de te c ting populalion c hanges. Information from a number of observers over a broad
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I Fis ur e 2-35 Keepins a Field journal: Recording observations in a field journal is wort/lthe extrn time and effort. As with,, checklist include exact location date and weather conditions along with detailed information about tl1e birds seen. Underline species names with wavy lines so the)! will be easy to locate at a glance. Supplement written material with sketches, where needed. Courresy of Stephen W. Kress, from The Nationa I Audubon Society Handbook for Birders, 1981 Cornell Laborato111 of OrnitholOBif

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Chapter 2 -A Guide t o Bird Watchin& As with a c h eckl ist, certain information is cruc::iall o n ote: date, t i m e of day, l ocation (distance and compass direct ion to nearest town name of county, state, and country if you'reabroad), weather co ndit io ns, a nd person s with you, if any. TI1en s i mp l y write down w hat you see-spe cies, numbers ages, sext's, and ot h er i de n t i fying characteristics. Underli n e species names with wavy or do u b l e lines, so they w il l be easy to locate at a g lance. A good technique for recording f i eld marks is to start b y l oo k ing at the bird's head and work your way b ack to the t ail. With practice, you can use quick sketches to map field marks and capture behavio r s (Sidebar 3: Sketching Birds in the Fie l d ). Onebenefitofta k ing notes is t hat it imp roves your pow ers of obser vation and memo1y. Think of a b ird you have seen many times, perhaps a Black-capped, Caro ll na, or Mountai n c hi ckadee. Can you sket c h it s b lack-an d wh ite pattern from memory? Exact i y whe r e do the black cap and bib begin and end? O n ce y ou have look e d c l ose l y at a bird a nd tried to write a descri ptio n or s k etch it, yo u will notice and r e member more abo u t it. Besides r ecording t h e spec i e s you see a nd their descriptions, you may want to descr ibe t h e birds' behaviors. If you find a nest. observe it for a period .of t ime a n d record the birds activities. Accurate field notes about behavi or are fust as c r it ica I as detailed descript ions of bird sighti ngs. For the fie ld biologist, behavioral notes are a source of dat a on h ow a bird relates lo its environment, Just as laboratoryexperi m ents prov i de the database for a physical scientist. Take com p let e no tes. You neve r can t e ll what seemingly portant facts may l ater become decisive. Greg But c her a former gist at t h e Lab of Ornithology a n d editor of Birder' s World magazine tells about watc h i n g what h e thoug h t was a Hooded Orio l e ( a resident of the southwes tern United States) singing in Nianti c Connecticut The son g sounded funny, t h o ugh, so hew role lt down, syllabl e by syll a b l e Later h e discovered t h e exact same descript i o n of an o r iol e s song i n his field guide-an d l earned that h i s b ird had actuall y be e n a fir st-year male Orc h a r d Oriole, a co m mon bird i n his lo cat ion. A few nuts-and-bolts c onsid e rati o ns: you can keep yo ur notes in a loose-l eaf notebook or a bound notebook Wat e r proof ink is best, but you can use pencil. I f you do use ink sele c t paper with i1 high rag it wi ll ho l d t h e i n k better and will not yellow w ith age. You'll a lso need a technica l pen with a t i p of approximate l y 0.35 mm; pens that d raw a n arrower line are too likel y to dog. Such p ens are avail abl e at art supply s tores. Keep t hem in p l astic bags, especial l y whe n traveling, to conta in leaks. The cardinal rule, and one lhat requires a goo d bit of sel f-disci pli ne, is to record everyth ing in t h e field as i t occurs. You can t possibly remember at the end of a lon g day, everything that happe ned. Write I h ings down at once, before you r memories slip away. If you hate writing i n t h e field take along a cassette recorder record your stream-ofc on sciousness account, t hen transcri b e your no tes after you gel h ome. Mi crocassette players that f i t i n a shir1 po cket are great for thi s purpose. B e ( Conlinved o n p 2 ) Har1dbook of Bird BiolO[jl.j 2

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2 Sidebar 3 : SKETCHING BIRDS I N THE FIELD Stephe n W Kress A quick fie l d sketch, with pertfnen l field marks n oted, can be invaluable when you are trying to recall exactly how a bird l oo ked or behaved. Be cause a sketch can replace part of yo ur written description, it also ca n save you some writ ing l ime in the field a l though it should be accompanied hy thorough notes. In addition, a !' ketch w i ll allow you to convey yo ur memorie s 1 0 othe r s m uch more dearl y than you cou l d with just a written record. A few basic techniques wfll all ow no matter how l ittle draw ing experience he or she has had, to make a useful sketch. Start your field sketch with an oval that apprmdrnates Stephen W. Kress the gener a l p r o p ort i o n s of t h e bir d Regardless of w hE!ther you inte n d to sketch an ow l heron, or robi n t hey all have oval (egg-shaped) bod ies (Fig. A). It is the d ifferences i n wings, tails, and legs that g ive each species a distinct ive form. Watc h carefully to see at what angle the b ir d h o lds its body, t h e n b e gin to assem b l e body parts, o u t l ini n g \ \ \. A. Use Oval s to Begin y our Bi r d Ske t c h: rhe bodies and heads of most bi r d species are roughl y oval in s hape so yo u can begin drawing b y placing ovals of the right size in the oriental ion ) 'Oll wish tv portra y Then ai.Jd rhe distinctive tess, wins> tall, and beak for your species. Drawing b y Anne Senerhill Fattst, from TI1e National Audubon Snciel y Handbook for B irders, h y Stephen W. Kress. 1981. Cornell Laborator 4 of'Omithologtl

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Chapter 2 -A Guide to Bird WatchinB head and neck, wings, tail, and legs. Concern yourself w ith the proportions of thedifferentpa!ts toone another and the position of attachment, a lways referri n g to the li ving bird. Draw w ith s m oot h flowing lines to achieve a n outl ine sketch of t h e bi rd. Don't worry about erasing mistakes or lines you don' t like. The goal s h ou l d be to capture shap e and po sture with as few lines as poss ibl e before the bird fl ies away. Portray most behaviors by chnng ing the posture of the bird's body (po sition of the and t h e posit ion of its appendages. I f you see an unusual bird or or1e you can t iden t lly quickl}' draw a s tandard per c hingpostureJnd 2 -51 then add details to illustrate distin ctive field marks. caref ul l y noting these in the margins of the page (Fig. B ). Practice by sket ching tam e birds s uch as captive parakeets, pigeo ns, or feeder birds. Perched postures a r e easie st, but it won't take long befo r e a f ew pencil lines wil l also capture the movement of bird s in flight. S No\vy SRI "AI-1-t i/.IE NYJR, .JV/IIE '21 a9o01 WIAJb : 0-10 MPH LAc.Y BACK. :sw PLUio t E'S 'fE.LLOW IS 8LAC)<. ftJPIL Figure B Sketc hing for Identification: When you e ncounter a bird you do not recognize. first make 11 quick sketc/1 of the general shape, Then add notes in 1he margins to data if all the field marks Jnd ienlures you nhserve. Or.rwfng by Anne Senechal Faust, from The National Audubon Suciety Handbook for B irders, by Stepheni!V, Kress, 1981. Hamihook of Bird Biolofjtt

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2 Stephen W. Kress awa re, though, that it's easy to end up with a shelf full of untran scribecl cassettes I f you need to refer back t o a specif i c in c id ent, find i ng the right tilpe can take a whi I e. Still tapes are better than no record at all. K eep i n mind, too, that cassette recorders break and batteries fai l P e n cil points can a l ways be sharpe n ed with a pocket knife or even with your teeth in the fie l d. Finally, r egard less of th e technology you use to record your obser vations follow these three rules at all times: record your observat lons as soon as possible after making them; don't consuh references before writing up your field notes-your impression of w h at you actually saw may be infl uenced by wha t you think you should have seen ren dering your notes less accurate and useful; and never change your notes-these are the records of your observations and should remain as you first made them. Once you've completed you r initial field notes on your excursion into the field, you have several opti ons. 5o me observers consider their recordkeeping done at this point. Others enjoy usi ng their fie l d notes to compose a more str u ctured set of records organizing the materia I i n various ways for easy access. The most devoted observe r s may use the straightforward, standardized note taking system established by Joseph Grinnell in the early 1900s which is descr i bed in Herman (1986) Thi s system in its entirety is too demanding for most recreational b i rd ers to use routinely, but aspects of it can be adapted to the needs of the weekend naturalist. One enjoyab l e way to Jearn a lot about individual species is to keep s pecie s accounts transferring observations from your field notebook i nto anothe r notebook that you've organized by species (Fig. 2-36 ) Then a ll your observations on say, the B l ack-capped C hi ckadee will be grouped together. A l oose-leaf notebook is the best choice for this effort, because it allows you to add pages to you r ex i sting notes on eac h species. If you follow this pro cedure for a few species that are of parti c u l ar i nteresl to yo u you'll soon become an expe r t on t hem. Now, what are you going to do with a ll this dutifully recorded informatron?.At first it's not crucia l that the data )'OU' ve gathered be published. As you learn to observe birds closely, you a r e learning far more about the sped fie bTrd you are watc h ing than you could ever learn from a book. But even i n the beginn i ng you sho ul d get in the h abit of reporting you r s i ghtlngs to your l ocal bird club, whTch will prob ably use them to update l ocal a nd regionJ I checklists. You might even want to fi l e your daily chec klist s with the club. The va lue of your lists in creases with time, providing import ant baseline data for detecting popul ation changes. Information from a number of observers--you and your fellow cluh members-over a b r oad area can serve as an early warning signa l that a formerly abundant species is experienci n g a seri ous population decline. Also many journa l s produced by state bird organizations wel come carefully documented r eports for publication. Your local bird can probably put you in touc h with the r egional editor for your local ity. And, if you l ive near a city, county, state, or national park or any other sanctuary o r refuge check with off i cials there to see i f they ------------------------------------Cornell Laboratont of Ornitholo[jtt

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Chapter 2-A Guide to Bird Watchin9 S....t. ;J .5 ...b.-e.. b.a<') GL 2 Fi g ure 2-36. Sample Page from a Species Account: An enjoyable way to learn .1bout particular birds is to organize your obser vat ions by species, accumulating them over time into species accounts. Courtesy of Stephen W Kress, from The National Audubon Society Handbook for Birders, 1981. Handbook of Bird BioloaLf

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2-54 Stephen W. K ress would like reports of yours.ightings to maintain their check l ists. F i nally, if you begin keeping detailed species accounts you will probab l y accumulate enough i nformation to write short reports on those species forpublkatlons, particu l arly i f you pick species that have not been well studied. You could be come the regiona l expert. Reportine Rare Birds If yo u see an unusual bird, make your notes as deta i led as pos sib le, because val idation of such sightings may well depend on your notes Record details of color, plumage, and behav ior, as well as the conditions under which you are making the sighting, s uch as t h e lighting and your approximate distance from the bird. You might even make a quick sketch. If possi b le, photograph the bird and tape record its songs a n d calls. When you report a rare bird or even a cornmon bi r d in an unex pected season (a B l ackbu r n ian Warbler in Michigan i n winter, for i n stance), your observation may need to be verified before it is accepted as part ofth e officiill local, state, or nat i onal reco r d. P rocedures vary from state to state, but as an examp le, t h e New York State Avian Re cords Committee (NYSARC) a group of experienced bir ders, rev i ews the accuracy and compl ete ness of the field description i n eac h report, then de c ides whether to accept or reject the sig h ting. Listin8 Birds Many birde r s enjoy keeping (I variety of separate bird l ists, no\ necessarily as c h ecklists. T h e possibilities are countless-l ists of birds at the feeder, in the garden, or on a field trip; daily lists, weekly lists yearly lists or a "yard list. Li sti n g is especially fascinating during the migration periods. A daily list in t h e spring, 1'or example, follows the changes from the seed-eaters, such as fi n c hes, to insect-eaters such as warblers and fl yca tchers. I n species with sexes of different colors, you ca n keep separate records for males and fema les. You can compare the lists for d i fferent seasons and not e which birds migrate and which do not. Remember; the card i nal that nests near your back door may not be the same one you fed all winter (althou gh it oft en will be ) A yearly l ist may revea l important popu l ation trends in your area correspondi n g to habitat changes. Many bird watchers keep a life lis t-a record of every species they have ever seen with the date and p l ace of the first s i ght i ng. The life l ist, l i ke sol itaire is your own game in which you make your own ru les concerni n g which species to cou nL Few birders would cons ider the co lorless blur that flas h ed past j ust as so m eone ca l l ed out "juvenile Lincoln's Sparrow" an h onest candidate for the i r life list, however. The constant cha ll enge of t he life list widens the scope of your bird watching ac t ivities and leads to exc iting new experiences with b irds. Standing as constant goals are the North Ame r i can life lists of some expe r t bird watc h ers, a few of whom topped th e 700 mark sometime ago and are now aim i ng for 800 North Amer i can species. Few of us ---------------Cornell Laborator'l of Orrtitl10loB'I

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Cllapter2-A Guide to Bird WatchillB wil l ever attai n s u c h lists although it is fun to try. People vary in their attitudes toward life lists. Some derive their greatest pleasure from just watching famil i ar b irds in their own habitat ; others find great sat isfaction in travel in g from place to p l ace c h ecking off the "lifers.' But it is sad when the life l ist becomes a birder's only goal, because so m any opportuni t ies for enjoyment and conr-ribution s to bird conservat i on are overlooked Hora ce's go ld en mean-" Mod e r ation 1n all things"-applies to bird wa tchin g as well as It does w oth er human ac tivities. CountinB Birds Counting birds accurately requires lots of pract i ce It's not hard to count a few chickadees or a smal l flock of crows, of co urse but when the birds fly past you in mu l titudes rather than dozens, or when several spec ies f l ock together, cou nting accurately can be very c h alleng in g. How ca n you judge th e size of a mixed flock of Canada and Snow geese that stre t ches from horizon to hori zon or a huge roi ling mass of foraging blackbirds? But even difficult, l aborious counts are more u sefu l than "ballpark estimates.'' T h e challenge is to give as
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2 Figure 2-31. The "Blocking" Met hod of Countin g Birds: First co untth e bird s in.1n frrmgin ary blo ck of t ypical density iro m the tr,1iling end of the flock ( thi s avoids the distrac tion of bird s flying into /he 1>/uck/, Tlum visuall y superimpose the b lo c k onto the entire flock a nd estimate how m a n > times it fits. Finally, muftipt y till s number by tlw number or bird s in the original block. I n thfs e1<<1mple, the block contains 1 7 birds .md (its i nto the flock a iJout 3 limes givins an es limal e of 5 1 b irds. The r e are acll/olly 60 birds in the t1ock. c Jll d J J. ,.._}: .... 41.. ..l .# -l.,... b Stephen W. Kress Jl..,. Jl.. .#.. .. ..t ..t:J. Jl.. ..-1. .l.. ,... ..,.. j_ ItA. ... ..( .... Figure 2-38. Practice Flocks: Bird flocks vary widely s hape, a l)d density. Use these examples to practice yout countin g lechnique. The actual number of birds in each flock i s given at the e nrl of the c hapter Cornell Labor atorq of Ornitholo[jtf

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Chapter 2 -A Guide to Bird Watchin9 a group that r ep r esents 50 o r 100 birds and see how many times th i s block f it s on the flock as a whol e. Concentra t e o n m e morizing impressi o n s of what flocks of d i f f e r e n t sizes look l i ke Practice by throwi ng r i ce g r ai n s out on a tab l e t op, m ak i ng a qu i c k estimate, a n d the n checking you r s uccess. W i th practice yo u can develop mental images of diffe r ent-sized flocks of var i o u s shapes (fig. 2-38). T h e est i m ates of diffe rent obse r vers l oo kin g at the same birds va r y to a s urpri s i ng deg r ee, but accu r acy is i mportant. Many Norlh Amer i ca n bird cens uses a n d surveys rel y on a m ateu r pa r t i c i pants, and the s u ccess of these important stud ies depends la r gel y upon lhe counting s k ills of part i c i pants Conclusion We are all teachers. O u r fascinat i on with bi rds i s one of the g reatest gifts we ca n pass on to o th e rs-friends ne i g h bors, family, and espe cially child r en More than 60 million Amer i cans al r eady wat c h birds so it appea r s that birds t h e ms e lves ma y b e the ultimat e e nvironm e nt al edu cators All we need to do i s d i rect more of the uninitiated into the r ealm of bi r ds closi n g the c r i t i ca l gapofdist a ncebetwee n bird a n d hu man, a n d let the birds do the rest w ith their m agic. In itiate a newcom e r with a close enco unter w i th a Great Blu e Heron liftin g o ut of a mist y wetland, and the convers i on starts (Fig 2-39). You ca n c ontinu e b y H andbook of' Bird BiolOfJlf 2-57 Figure 2-39. Creal Blue Heron: The magical experience oi watching a Great Blue 1-leron take t7ight from a misty wetland may bC' "1// that a newcomer needs to begin a lifetime of fasci nati o n with birds, illlcl with it a con ce m for th e 11Jiur.11 e'nvironmen t Photomontage by Marie Re,1d.

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2 Stephen W Kress s h ari n g intim a t e views of e legant waxwi ngs p l ucking apple blossoms a nd bluebirds resplendent in g lowin g color. ''How could I h ave missed all of th is?" they ask "No l onge r," they insisl. Perhaps it is envy of th eir flight, col o r s1 and stam ina, or delight in their e n c hanting songs a nd r emarkable behaviors. P erhaps it is awe at their m yster ious migrat i on a nd boundless vitality. For whatever r eason, birds cap tur e our a tt e nti on and o ur im<)gination whether we s t ay at h o m e and l et the migrant ilocks flowintoour lives and out agai n, or we pursue them by foot bike p l ane or ship. Once pe o pl e notice birds commitme nt to their well-being u sually follows. Thi s con n ection is a t the soul of birding: the b i rds' f ut ure is intimately tied to our own. The Birder's EssentiaL Resource Guide There is a mountain of information avail<1ble these days to birde r s w ith va r i ous l evel s of in te r est and exper i ence in the form of field and aud i o guides c h e c klists and travel g uides, textbooks, popu l a r magazines, sci en tifi c journals web sites, ge n eral and l eisu r e reading abou t birds. Due to the volume of inform at ion available a nd the con tinual release of n ew publica tions of interest to bird watche r s a nd other en thu s iasts, to list justa few of t hese resources here would be vast l y incompl e te. Please visit the Home Study Co u rse website < www .birds.c o mell.eduthomestudy > to view t h e Birder's Essentia l Resource Guide online a nd see what r esources, o l d and n ew that we believe might be of in terest to yo u Come// Laboratortt ofOmitholO[)tt

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Form and Function: The External Bird George A. Clark1 }r. O n e reason peop l e low b irds i s t hat they are so beautifu l and so var ie d. Conside r col or alone, i g n o r ing for the mo m e n t t h e m a n y var i at io n s 111 features s u c h as bi l l l ength and feat her shape. B irds come i n every conceivab l e hue. Any experienced bi r de r can easil y t hink of a b ird for every color of the rainbow, even among the birds of North America: Northern Cardinal, Baltimore Orio le, Yellow Warbler, Green Jay, Eastern Bluebird Indigo Bunting, and PurpleMartin.ln fact, the blues alone vary from the subtle hues of the Blue-gray Gnatcatcher and Cerulean Warbler to the deeper tones of the Blue Grosbeak and Steller's Jay. Furthermore some spe cies, such as the Bunting simultaneous l y display an amazing army of these colors. N early every color we can imagine can be found on at least one of the n early 1 0,000 species of bi rds. Most o f the remark a b l e c o lors a n d othe r aspects of n b ird's e x t erior are speci aliza ti o n s of i t s skin-not o nl y the coveri ngs of the face, beak, and legs, bu(even the feathers. Feathers occur o n no other li ving animal: i f it has feathers, it is a bird. Some years ago a mu tant breed oi nearly featherless chickens was studied with the idea that these birds could be sold cheaply because they would need little or no plucking. It turned out that 1he extra heating required 10 keep these birds warm more than offset the savings on plucking; featherless birds it would seem, don't have much of a future.

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3 GeoreeA. Clarl<. Jr. This c h apter introduces feathers-the ir lo cations, structure, func tion 1 care, and deve l opment, including their replacement through molt ing. Then we move to other parts of the skin s uch as t he b ill and legs, where a feathered covering would i n many cases be a liability. Each part of a bird s exterior co ntributes to the unified whole, and we g ive special attention to the color and pattern of the ent ire bird t consideri n g 1 for example, why some birds have vivld colors but others are dull. Feather Tracts Examine a plucked chicken or turkey ready for the oven. You can see the sites where feathers were attached known as follicles as small indentations in the skin. In most birds the feathers are not attached un iforml y over the body 1 but are g r ouped into fea ther tracts called ptery lae (singu lar: pteryla ) Between the tracts a r e regions of bare or less-feathered ski n called apteria ( singular: apterium ) (Fig. 3-1). Pt e rylo sis, the arrangement of feather tracts and bare patches, varies from one taxonomic group to another, and some groups have unique patterns. For instan ce, the corvid family, which includes ravens, crows jays, nutcrackers and magpies has a char acteristic ap terium In rhe midline of the ptery l a located on the back. Historically, s uch distinctive patterns have been important in classifying the main groups of birds. The feather patterns are symmetrical from one side of the body to the other and are shared by a ll members of a species. Although we know littlecllbout the possible functions of the many taxonomic variations in pterylosis, we can deduce that, for any given Fi gure 3-1. Distribution of Feather g r oup, strategica ll y l ocating feathers in tracts may allow birds to get Tract s on Plu cke d Bird: Dots represent away With fewer feathers ove r all, thus reducing the baggage they must fe(lthe r f ollicles, sites oi a ttachm e nt of carry in f light. Much as balding men comb their remaining hair to cover feathers Groupsofdots ,ofteninalinear a bal d spot, feathers from the feather tracts cover the apteria1 form ing pattern feather tracts termed pte rylae F eathetless areasbetvleen trac/Safe f l ight surfaces a n d providing insul ation without requiring a solid mass apteria of feathers. Groupi n g feather s in tracts also may a llow the muscles that move them to be smaller and more l ocalized-lighten in g the bird even more. As discussed in Chapte r 5 birds have evolved many such adaptations to reduce thei r weight and create an aerodynamic shape. In addit i on, apteria may aid h eat loss, as many birds raise their feathers to expose bare skin when becoming overheated. A iew k inds of b irds, most notab l y penguins have a continuous ptery losis with no apteria. This arrangement he lps to prevent water irom penetrating to the penguin's s k in and chill ing it. Penguin feath ers are so good at trapping an insulating layer of a ir near the body that the skin stays dry even w h ile the bird Is swimming and d i ving. Adult Ostriches from Africa also lack apteria, but their embryos have them Because many researchers believe the stages that developing embryos pass through ind icate the stages their ancestors evolved through the lack of apter i a in adult Ostri ches is probab l y J. secondary condition. The ancestors of Ostriches undoubted l y had a more typical feathering and perhaps those of pengu ins did as well. Cornell Lnhorator4 of Omitholo811

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Chapter 3 -F o r m and Function: The External Bird Feath e r s li e on the body a nd wings with impressive neatness. Such orderliness h elps to produce the 1 tidy, st reamlined cover of feath e r s that is crucial to a bird's survival. 3-3 Feather Form and Function Li"adfng Edge of Wing From an eng i neering viewpoint feathers are n ificent-t hey accomplish so much with so li ttle mat er i a l. Oftheirmany functions, the most import.Jnt are (I) insulating and prote c t ing the skin and body, ( 2) providing the smooth streamlined surface area required for effi cient flight, a n d (3) p r oviding pattern and color, which are impo rt.Jnt in socia l behavior as discusse d l ater in this chapte r and in Chapter 6. Feathe r Structure Examine a f!'lather from the wing or tail of a bi rd. Note the rat h er stiff central s haft and the two broad vanes extending from opposite sides of the shaft ( fig 3 2 ). I n b irds capable of fli ght, the outer wing a n d tail feathers are typically asymmetrkal, w ith on e vane n arrowert h antheother. Thi s asymmetry prod uces greater rig i dity on the leading ( narrower-v aned) edge of the w1ng, which is needed to maintain the streamlined shape of feathers during fli g ht. I t also causes individual wing and tail feathe 1s to twist as they move throug h the a i r which is essential for flight (see Figs. 5-17 and 5 1 9). In general, vane w i dth be comes less symmetrica l as you move farther from the center of t h e body. Thus, a feather from the middle of the tail will be more symmetrica l than one from the edge of the tai l ln t h e same way, the vanes of the innermost f light feathers of the wing may be a l most symme t rica l whi l e the vanes from the outermost feathers a r e qu ite differenl in w i dth (fig 3 -3). When flight has been lost secon darily through evol ution, CIS in certa i n rails on isol ated oceanic islands the primaries have lost their asymmetry. The asymmetry in the fossilized primary f eathers of Archaeopteryx i ndicates that this earliest known bird could indeed fly, but whether it was a strong flier remains con troversi<'tl. T h e centra I shaft i s divisible into two sections.1he l ower portion part of whi c h lies beneath the skin is the cal a mu s ; it is hol l ow and has no vanes. Above the calamus lies the rachis, which is essenllal l y soli d (Fig. 3...-4). The vanes, extend ing from the rachis, a re made up of a series of parallel branches called barb s At right tt)' In \ '"'e width with n,Jrrowvr \liJnl' vn erlf.wor.vmg t/1;.1 lead s In fli s hl lermed the o uter van e The wi der vane Is caller/ ll1i" inner Vilne. Symmetrio/ Figure 3-3. Asymm etry of Van e Wid th in W i n g a nd T ail Feathers: The nMrower /OUt er) v .rn e of e & c h Ieath('( located towarcl 1he /ea
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3 Figure 3-4. Structural De/ail of a Typical Contour Feather: The (&othe r is di v i dec/ into two segme nts : the lower, hoiJcJ\\' vaneless calamus; and the upper, solid rachis, to wl1ic h the vanes allm : h Tl1e van e s comist of branc hes callecl barb s whrc h Jre lfkew ise fla nked by pam/l e i branclllets c alled barbules. Tiny hooklels un e.Jch d is1al l.mrbule c ,Jtc h onto e a c h adji[lcent prox i mal bar bul !JolditJg the barbs together lightly som e whnl fifi.e s l ri[JS of Velcro. Adapt e d from faaborg and Cfraplin (1988, p 1 5 I ig .!-II. Georee A. Clari<,Jr. } Proximal B a rbules of the Next Barb f 1 Distal Barbult!> u f [One Barb together by stroking from the base towCJrd the tip and see how neatly they fit against one anothe r formtng a smooth, co n tinuous surface This motion Is exac tly what b ird s do while they p reen, to smooth and ;Jdjust their feathers, zipping" them together. The large surface area of wing feathers i s particularly importantln providi .ng lift and thrust for Hight. The barbules not on l y hold the ba rb s together butalfow them to slide relat ive to one another; co n tributing to the feather's extraordinary flex i b iii ty. of Feather s When we think of a feathe!f we often visua l ize a flight feather from the wing; however ; thi s is just one oi the many types of feathers that birds possess. A single bird may have delicate and fragil e down feathers. largely vaneless bristles and strong feathers used in rlight Furthermore. eac h type of feather differs from spec ies to species, and w.ithin a s pecies, b y sex and age. Differences occur in size, shape, pattern, co l or and microscopic structure. Given a si ngle feather, an experie nced person with a microscope-and acc:ess to a large collection of bird specimens for comparisons--usu ally can determine the species, sex, age category, a nd thefeather'soriginal position on the body ( S idebar1 : Feathe r Detective).lnform at ion ofthissort can be valuable. Researchers studying the diet of nestlng Shar p-shinned Hawks, for example, cannot ki ll these pwtected species to examine their stomach c onten ts. But by studying feathers of prey t hat are dropped from the hawk's nest, they can learn the spec ies, sex, and age of the prey. Cornell Lnbora.ton1 of OmitholotN

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ct,apter 3-Form and Functio11: The External Bird C ontour F eathe r s Th e contour feathers a r e what you see when yo u look at a bird. Forming the outer shell of the b i rd's feather coal, the y are termed contour feathers because they give the bird its characteristic shape or o utl i ne. Unl ike other major types o f feathers, most con tours have tightly knit vanes that form a r elatively impe n e trable surface. Th ese feathers streamline and shap e th e wings to p rovide propulsion and lift in fl ight. The ti g htl y knit vanes def l ect air currents, minimizi ng the effects of wind and a l lowin g the bird to slice throu g h the a ir. When beaten agai nst the wind, the y a l so provide strong resi stance to ai r ; the bird uses this re sist ance in ae rial m aneuvers, and in stoppi n g. Try to blow through the i n tact vane of a l arge win g feather an d you'l l see that onl y a n extreme l y s tron g wind can p e n e trat e suc h a surface. Contour feathers a lso provide in sulation agai n st extremes of t empe r a tur e. Because these feathers are aligned one atop a noth er likeshingl eson a roof. wa t er tends to run off. A bird in the rain t h erefore, remains dry a t th e skin thanks to its feathe r s I f this protection becomes disrupted ( for exa mple, i f the feathe r s be come oil-soaked), the bird can die within seconds from hypothe rmia. H ealt h y birds, you may h ave noticed always look trim and n eat. Each contour feather has a set of specialized mus cles, l ocated beneat h the surface of the skin around the follicle, whi ch helps to position th e feather. Without such muscles to hold feathers in the right positions, the feat h e r coat would be disheveled. In some cases, mu scle s heets immediately be n eath the s kin ac t together with the individual feather muscles to coordin a t e movement of the feath e r s within a tract. Individual feathers usually ca n't move very much but the i r move m ent can be hi g hl y conspic uou s when, for examp le, a display in g ma l e grac kl e elevates the feathers over most of his body (Fig 3-5) or w h e n an adult male R ed-winged Blackbird displays his bright r ed e paulette s (sh ou l der patches ) (see F i g 6-38). Even more spectacular i s a male peafowl spreadi n g hi s tra in of feathers ( F ig. 3-6). The largest contour f eathers in man y birds are the l arge flight feat h e r s on th e wing, called r emig es, and the t ai l feathers called re ctrices Beca use the r emiges of a l l flying birds provide lift and propu l sion 1 it i s imporlantlhatthey not be d isp l aced by stro n g aircurrent.s. Thus they are attached f irmly to the b o nes of the w in g eit h er directly or indirectly via ligame nts, unlike most otherfealh ers, which attach o nly to the s kin Th e rectrices are conn ec t ed to o n e anot h er by ligaments with only the innermost attach in g directl y to the tail bon e ( pygostyle ) via ligaments. ConlilltiC'CI on p. 3 01 3 Figure 3-5. Co mmon Grackle Displ ay 1vith Fe.1/llers Ere c t: Eac.:ll contour feather has a set of speci
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3 Sidebar 1 : FEATHER DETECTIVE Mike Lipske (Excerpted from ro Dawn Detective Rox ie Layboume a Feathe1 Clue," by Mike Upske, i n Smithsonian March 1982. Reprinterl with permission from the a whor and Smithsonian. ) On her way to becoming this country's absolute l ast word on the ide ntifi ca tion of feathers, Roxie C. Laybourne has not hewn to the tid y path. The c l utter on her desk at the Smithsonian Institution s t ands a solid six inches deep at th e left rear corn er and slopes to a cfepth of two inches near t h e right front. From m ountai n t o p l ain spreads a layered mass of routing envelopes, officia l letters, sc i e ntific texts, seminar proceedings and scattered scraps of paper. One small brown-and-white feather pennant on a sink in g ship, pokes up from the pi le. It' s from TI1 a iland but I haven t worked it out/ she says of the feather. On an adjacent table are more papers more b ooks h er b l ack mi croscope, a plasti c br ead bag filled with eag l e feathers, as well as sev era l small g lass boltles containing c harr e d bits of down floating in Ivor y Snow and water. Feathers, ones in need of a name !low steadily to Mrs.laybourne's ti n y office in the National Museum of Natural History. Aircraft engineers designing planes t o withstand colli sio n s with birds, send her tiny shreds of feathers scraped from jet engines. An archaeologist in New Mexico drills a hole in a 500-year-old sealed pot, p l ucks bright yellow and orange feathers f rom inside and mails them to Mrs. Laybourne in Washington. Feathers come routfn e ly from field agents of the U.S. Fish and Wildlife Service (FWS ) and the Federal Bu reau of Investigation. A systematic ornithologist andre searc h associate in the Smithsonian s Division of Bird s Mrs Laybourne i s also a part-time zoolog i st with the Division of Law Enforcement of the FWS. Short, square faced, she speaks in a thi c k Carolina drawl, and punc tuates her conversation with rolli ng hand gestures. Combing qu i ck l y throug h the crammed drawers of h er desk s h e pulls out plastic bags holding bird remains. From one s h e du mps a few bits of mang l ed fluff re cove red from an airp l ane engine following a bird strike in Te)(as last year Reading the scant evidence, she has conjured up a female Amer i can Kestrel. Th is strike occurred in Turkey,' she says of the nex t one, a grayish wing a nd one severed foot, sent by the U.S. Air Force. "Golde n P l over." On a m i crosco p e slide are mounted a few tiny, white strands of clown : I knew for ce rtain i t was a Buteo ( a genus of soaring hawks). It turn ed out t o be a R ed -tailed Hawk_ Probably a Red-tailed Hawk. You ha ve to be ca reful not to overstep your bounds. ''Re mark able woman," says Doug las Sutton allhe tim e a Smithsonian post-doctoral fellow for whom s h e was identifying feathers found at archaeo l og i cal sites in Labrador. That wor k she does with feathers, I've nev er seen anyone do. Bright as h e ll. Feathers for God's sake! That's a very diificult thing." I grew up as an ornithol ogist.'' says Mrs. Laybourne. ''I've been in t e rested in natural his tory and birds eve r sin ce I could walk. You get used to thinki n g of birds in cer t ain terms. People who band birds know the bird from hand l ing it, or seeing it in the fie l d. I know birds bet1er when they'r e dead." She was born in Fayettev i lle, North Caro l ina lhe year, s h e says, is not "pertinent. Her parents moved soon af t er to Farmville in Pitt County. "It was a smal l town You had plenty Cornell Laboratont ofOmitho loett F igure A. Roxie L aybourne W.uhes Soon-lo-bl'-idenlifie d Fi?athers. Photo c:ourtesy of Chip Clark of fields ;mel woods to r oam in Most p eople don' t. But t did. I liked to hunt and fish." She was graduated in 1932 from Mered ith College in Raleigh, with a degree in science and mathemat ics, and went on to work a t the North Caro lina State Museum of Natural History, where she l earne d taxi dermy and spent s ummers at the fed eral fisher ies station in Beaufort col lecting birds fish and other spec imens ior the museum and puzzling out prob l e m s in shark id en tifi cation. Graduate study in zool ogy at North Caro l ina Stat e University was fol l owed b y a master's degree in botan y f rom George Washington University in Washington D .C. She cam e to work at the Smith sonian in june t944, intending to leave Washington after a year But by November 194 6, she h a d trans ferred to OJ job at the Fis h a nd Wildlife Service, where she has worked since for many years w i t h the Bird and Mamma l Laborator ies, now with th e Division of Law Enforcement. As a S mithsonian research associate, she has an office
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Chapter 3-Form and Function: The External Bird 3 of an emp l oyee b ut no sal ary," she explai ns. I t was n ot unti l 1 960 that R ox i e Laybourne's pec ul i ar knack fo r identifying feat hers bega n to reveal itself. On October 4 of t hat year a turboprop Lockheed E l ect r a took off from Boston's Logan Airport burst into flames a n d p l unged i nto Winthrop w1th 72 aboard> Eight passengers a nd two ctew members surv i ved the 47-second flight-cut short by ,, flock of birds s u cke d into the E l ec tra's engi nes. The Federal Avia tion Adminis tratio n turn e d t o Mrs. Laybou rne and John W A l drich her supervisor at t h e time fo r h elp i n id e nti f ying fragm ents taken from t h e engi nes. "That was our first case.'' remembe r s A l dri ch, a lso a research associa t e in the D i vision of Birds. "An d it was a toug h o n e T h ey were a ll m a n gled. Finally we did nncl one whol e s t ar ling feather.'' T11e BostOf1 c r ils h cause d a n im mediate sc urryin g i n the indu s try, and a feeling that the effec t s of birds on airpl a nes was som et hing that h a d to be u n derstood. "It was one oi the first tha t ever h appened with b i rds," sai d one i ndust r y emp l oyee. "Lives were los t a n d a p l a n e came down out of the sky." The aircraft industy p refers to remain quiet about its bird stri k e re searc h People get hysterical when we take dead p i geo n s and throw th em i nt o r unning eng i nes," says a Pratt & W h itney public rel ations man. And we do.' A I Weaver a Pratt & Whitne y e 1 g i neer w h o has been sending Mrs Laybourne feather f r agments fo r ten years. says he is not espe cia ll y cu ri o u s abou t the species or sex of bi rds that f l y into e ng ines. But h e does wa nt to know the s i ze and i l i t i s a flocking bird, like c1 gull, "or a l oner ITke a h awk.'' W h ich is whe r e Roxi e Laybo urn e becomes .:1 good person t o know. "Feat h ers," s h e points o ut "will take a lot of beati n g. They're p r e u y t o u g h. That's one r eason you can identi fy the m aft e r the y go through something, l i ke a je t aircraft e ng ine a n d they 're all chewe d up. Th e first thi n g she doe s w ith t h e chewed up feathers that Weaver and ot her engi neer s sen d t o her is wash t h e m (Fig. A). ''You ca nno t i d e ntiiy di r ty feat h ers.'' After the feat her frag m ents have bee n soak eel in soap y I iq uid, rin sed a nd dried s hepu tsoneon a sli d e a nd under h er micr oscope. She i s a stude n t of the fine d iag nos ti c struc tures on the barbules of down (fig. B ) These barb ules a r e microscopic parts of a fe
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3 F eat her I dent i fica tion and the FBI The resource is often tapped by "outsiders'' who, in turn, add their own knowledge. II was, for e)('
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Chapter 3 -Form and Function: The External Bird a puzzle-ever y time you get bird remains, you don t know w h ic h species you have. W i t h every bird you're beTng put to a test. Even i f i t is the same species, the feathers co u ld we l l be from diffe r e n t parts or the b ird. And t h e dat e and locality of the strik e are i mporta nt. You see, you're putting a puzzle together, t r ying to figure out w h ere the pieces go. 3 I warn people, don't co m e to work with me-you may become ad dicted. Whe n peop l e say to me 'you do n t make much m oney i n museum wor k,' I always say 'you don't need as muc h -)'OU don't need to go on vacatio n s to enjoy yoursell. You've e n joyed you r day. Your wo r k is your recreation."' F i g ur e D D o u g las D ee d ri c k a nd Roxie L.1ybourne : Photo courtesv of Chip Clark. W hen I s p oke to her i n mid September, h er cur r ent r ecreation was identifyi n g birds for the Air Force. P lanes f rom a base in Nort h Car olina were h itti n g b irds at night -"So it's migrati n g bi rds," she said, fitting a pieceoft h ep uzzle. "They're anxious to k n ow what they'r e hitting. So far, I've i denrtfied Mourning Doves and Kil l deer b i rds that like the grassland habi tat of airfie lds. Also three bats." The Ai r F orc e had comp iled i n iormation on the birds that live at all the diife r e n t bases. I f t hey have bird problems, they may c hange fl i ght patterns, d iscourage birds by chang ing habita t or even m ove fl1ghts lo different airfie lds. Overall the bi r d hit most often is probably the Horned Lark," she tol d me. "In the United States a n d Europe, commercial airli nes are most l ikely to h i t gulls. I n Africa and Asia, i t's Black Kites. A ir Force planes often hit Turkey Vultures The Horned Larks weigh about o n e a n d one-hal f ounces (42.Sg), so l ike the vast maj ority of bird strikes, they do no damage and endanger no lives. Nevertheless, she said, "A s t rike is a lways a serious p r oblem, because you never know when it wil l cause damage." Mrs. Layb ourne's year s of work have helpen aircraf t manu-f
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3-10 Figure 3-6. Display of t h e Ma l e Indian Peafowl: In a s p ec t acula r dis pl.l)l f)i feath er co ntrol th e peacoc k face.o o n e or more f e male> and lift s and f.111S Ills k tr.Jin w h i l e r ustlin g his wing leatf1ers .m cls tJmp i n g his f eet. The train co n sist s o f near! ) 1 5 0 uppertail co v erts w i th as m a n y eyes" .wrl is supp011c d l>ehind IJI' th e unad orne d r ec trfces. Pho t o co urtesv of l sido r J eklin!GO The oute rmost r em iges a r e the prima ries, recognized by their attac hment lo the skeleton of the hand" (see Fig 1-8) T o meet the demands of powered flight the primaries must be s trong yet flexible. Depending on the species, birds commonl y h ave between 9 and 12 well-de veloped primaries. Project i ng rearward from the forearm of the bird w in g i s anothe r row or r emiges ; these are known as s e c ondaries. I n b oth flapp in g and soaring f l ight the secondaries provide lift and thus function like the fixed wing of an airp lan e Among b irds as a w h ole, the numb er of second a ries varies more than r he number of prima ries, ranging from 8 to 32 (Van T yne a nd Berger 1 qs9) Th e higher numbers occur a mon g birds with long wings, s u c h as a l batrosses whi ch n eed a large w in g surface for soar in g f l i gh t over water. In most flying birds lhe sec o ndaries attac h directl y to the uln a bone in lhe forearm via ligaments. On many isolated uln(l s1 such as might be washed up on a beach you can see the bony bumps that wer e points of attachment for the sec ondaries. The other major sel of flighl feat hers in most birds, the rec lrices ( !ail feat hers) a r e parlicularly important for stability and control in flight somewha t like the t ail of a ch i l d s k ite ( Thomas a nd Balmford 1995). For in stance, forest-dwel lin g h awks, such as 1 he Northern Goshawk use their tails as rudde r s to help gu id e them lhrough an obs t acle c ourse o f trees. Among flying b irds the numher of r ectr i ce s ranges from 6 to 32 with t h e higher numbers occ urring in l a r ger birds (Sid e b a r 2: Feath e r Facts). To make accurate r eferences to ind i v i du al feathers, ornith o l og ists have developed a standardized numbering system (Fig. 3-7). B orde rin g and ov e rl yi n g the remiges and r ectr ices on both the upper and lowe r sides a r e r ows of feaihe r s called c o verts, which pro v id e insulation, color, and pattern on the w in g s urf ace and perhaps most imp o rt ant, contr ibui e to the streamlined s h ape of the wing and (ContitJu e d on p . H 2! Laboratont of OmitholofJtl

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Chapter 3Forn1 and Function; The ExternaL Bir d S idebar 2 : FEATHEI\ FAIT S Sandtf P o d ulk.a N umber o f feathe r s How ma n y feathe r s does a bird have? As you m ight expect, big birds tend to have more than smal l b i rds. The reco r d low count (contour feathers only) is 940-fr om a R u by t hr oated Hummi n gbird (We tm o r e 1 936). The highest number was reported by Ammann (1937), who (patie n t ly) cou nt ed 25 ,2 1 6 cont o ur feathers on a Tundra Swan. Of these, 80% (20, 177 ) were o n t h e h ead and n eck. This distribu(ion ls not sur pri s i ng since swans are so c learl y l o n g-necked, b ut eve n s h ort n ecked birds have a hig h percentage of t hei r feathers on the head and neck w here ma n y small are packed close l y toget her. Feather number also varies w i t h a bi r d's need fo r insu l ation. For ex amp le, b irds livi ng i n cold cli mates have m ore feathers in w i nter than in sum me r Wet m ore ( 1936) found t hat in winte r Whi te-throated Spar rows have about 2,500 co n tour feathers, b ut i n summer they have on l y 1 ,500-a 40o/a decrease. In add iti o n aquatic birds tend to have more feathers t han ter restri al species of a s imil a r due to the rap i d loss of heal experienced by bfrds in water. Heat retentio n is probab l y a lso t h e reason smaller birds tend to have more feathe r s per un i t body weig h t than do la rge birds. Like a human a bird generates heat t h rough the m eta bolic reactions tha t take place thr oughout its body and i t l0ses m uch of t his heat ac ross its body surface Therefore t h e more surface a r ea a b i r d has r elat i ve t o its heat generating comparison known as the surfacet o-volume r atio-the more quickly i t will l ose heat Because small birds ten d to h ave a h igher surface-to-volu m e rat i o, th ey lose hea t rapidly, and thus nee d more feat h e r s for each u nit of body weig h t than does a lar ger bird S iz e of f e ath e r s B i gge r bird s n o t on l y have m o r e feathers, they have bigger feat h e rs. Thus, if yo u f i nd a feather on the of Bird BioloB!f J.n g r ou nd, its size is a useful clue to the size of the bird it cam e f r o m Not surprisingly, the s m a llest co n tou r ieat hers known are from the wor l d's smallest the feathers from the eyelids ot' the Bee Hummingbird Me m e r e l y 1 /63 of an Inch (0.4 mm ) long! In contrast, the c o n tour feathers forming the peacock's tail are nearl)' 4,000 times l onger up to 5 f eet ( 1.5 m ) in l ength. Weight of F eathe r s Feather s are, indeed1 "light as a feather Although the feat he r s of some birds s u ch as owls, seem to make up half their volume, the feather coa t common l y accounts for only 5 to 10 % of a bird's weight. Thus, a chickadee weighing four tenths of an ounce (1 0 gl-
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3 George A. CIJJrk, Jr a Fig ure 3-8. Examples of Modified Contour Feathers: a : Body feather of a pheasant. It has a smaller afterfeather with all of the barbs free and soft. b: One of the two long, central rectrices of a motmot ( Momotidae ) from the New World tropics Along the terminal half of the shaft the barbs have fallen away, leaving a racket/ike tip. c: Rectrix of a Chimney Swift. The tip end is devoid of barbs and spine/ike. d: One of the shorter feathers in the Ntrainu of the male Indian Peafowl. All of the barbs are free except near the tip where they are hooked together to form a continuous surface for the colorful ueye.u e: The plume from the back of an egret. The few barbs a r e little more than willowy filaments. f: Breast feather of a turkey. The barbs in the vanes toward the tip gradually s horten producing the truncated or squared-off effect. g: Body feather of an Emu. Its afterfeather i s so similar in size and structure to the main feather that it is indistinguishable, thus forming a double feather. All of the barbs are free. h : Body feather o f an Ostri ch. The many long, soft barbs with their countless barbules, unhooked and fuzzy, g ive the feather its characteristic Ouffiness i: C rest feather from the Sulphur-Crested Cockatoo of Australia and New Guinea. The curliness results partly from one side of the shaft being exceedingly flat. Drawing by Charles L. Ripper. Cornell Laborator'1 of OmithoiOfjlj

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Chapter 3Fortrt and F tmctlon : The External Bird tail. Just lik e air c r a ft fly in g animals need strea m l inln g to reduce f ri c tion with the air; streamlinin g greatly reduces the en e rgy needed to f l y Some con t our feathers have an af t e r feat her resembl in g the maTn feather but i n miniature growing from the lower shaft. W e ll developed afterfeathers co n t a in a s h aft and two vanes (fig. 3-8a) Afterfeathers provide e xtra i nsulation a nd are especial l y wel l dev e loped in grouse many of which l i ve in seasonally col d or arct i c regions In the (lightless Australian Emus, the aherfeathers areas large as the main feathers (Fig. 3-Sg). These big fluffy contour feathers help to rorm a thi c k prote c tive coat that is use ful in the d e nse brush of the Australian scrubl a nds. The feather coat is so tough that these b irds can cross the Australian o utback's sturd y four-foot-high sheep fences topped with barbed wire simpl y by running fast, crashing into them, and somer saultin g over. In the process, the y leave behind a pile offeath ers hang ing on the barbed wi r e (Fig. 3 -9).1t'squi t e a testimony to the protective valu e of the f eat h e r coat-one hates to think what would happen to a hum a n who tr ied t o cross such a fence by smashing in to ill Some co ntour feathers have become highly modified for special fun ctio n s (see Fig. 3-8). Among the most bizarre are those used in courtshlp disp lays, s u c h as the elaborate ornaments of the male birds of-paradise (Fig. 3-10 ). Motmots nightjars, and other species have odd feathers with a wirelike rachis for their displays (Figs. 3-8b 3 -11 ) Oth er m odifica tions are more subtle. In most owls for instance, the l eadi n g edge of the firstsevera I primary feathers has a loose fringe, and the dorsal surface of the Inner vanes of most flight feathers has a soft ' pi l e" (Fig. 3-12) These modifications render the feather coat very soft to the touch. M o r e important, they a llow owls to fly very qu iet ly, creatin g little noise even in the high-frequency range that their rodent prey h ear so well. Other special contour feathers I nclude the wax lik e t ips of some wing and tail feathers of waxwings (see Ch. 7 Sidebar 5, Fig. A )i the c url y feathers i n the erecti le crests of the Australian c ockatoos (fig. 3-8i) ; and the stiff, straw like crown feathers of the Blac k Crowned-C r a n e of Afr ica (Fig. 3-13) Some birds, such as the American Woodcock and Common Snipe, have conto ur feathers modified to produce sounds (see Ch. 7 Sidebar 1 Figs. C a nd E). Bri s tle s a r e highly special ized contourfeathers i n which the rachis is stiffe n e d a nd l;;1cksbarbsalong its outermost parts ( Stettenheim 19 7 4 ) Among the bestknown bristles are rictal bristles which proje ct from the baseofthebeak in birds that catch insects, such as flycatchers, night j a rs, a nd some New World Warblers (Fig. 3 -14a). Some ornithologists have suggested that ricta l bristles mlght funnel insects into the mouth of Bird Blolo911 3-13 Figure 3-9. Holy cow! I hope ch,1r n e w hair replacemenr s tuff works on feilthe r s

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.1-14 Figur e 3-10. Display Feathers of Male Birds-of-paradise from New Guinea: a: Wallace\; Starorl.1rdwing. b: Greater Bird-of-paradise. c: Blue Bird-of-paradise. d: Kingof-Saxony Bird-of-paradise. e r Superb Bird-ol-paradise. f: Magnitlcenl Bird-al :paradise. Note in band c the smoky effect oft h e long filamemous leather!}; incand 1 ; the lonp,, ba r bless wires;" in e1 the etectile cape and bib; and fn d the two extraordinarily long c rown plumes which have vanes on on/) O P e side.
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Chapter 3-Form and Funct i o n: The External Bird 3-15 a Figure 3 -11 Modified Flight Feathers: a : Two extre m e l y modi tied remtges adorn the male Standard-winged Nightjar, a s mall, nighthawk like b i rd from centr al Air lea. The second primary on each wing a broad van e t owa rd the lip of a very slender shaft. It i s approximately 11 i nches (28 e m ) l o n/JJ a nd well behind the ot h er win s ieathers. When flying in the twilight with the shafts oi the t wo feath e r s practically invisible a nd their terminal vanes flappin/JJ the starli n g-sized bird looks as tho ugh it wer e be in g pursued by two little bats. Drawing by Charles L Ripper. b : 7Wo e :ocuemely modified r ectrices grace t h e unmistakable rnal e Marve lou s Spatule.t;Jil, a humm ingi)ird from the Andes of n ortherr Peru.. F igure 3-12. Features of Owl Feathers that Produce Silent Flight Owls achiev e very qu iet flight with t wo specializa tions of their feathers. F irst a soft fringe on Rad1ises the margin of the o ut er vane of the first Inner two or three primary feathers s o f tens the Van e co nt ac t between the air and the leading edge of the wing Second, a vel very pile is located on the dorsal surfoce of the i r n er vanes of all remiges a nd to a lesser exte nt, /he tee/rices. This pile a fur-like, filamentous co mponent oft/l e barbs and barbules is very efficient at deadening any scraping sound /hat may be made as the remiges slide againsteilch or h erdvri n g flight. In addition to owls Nort h ern Harriers exhibit this pi/eon their feathers and probably benefit greatly from silent flight as the y cou rse or ho ver over meadows in pursuit of rodents. Pile on Dorsal Surface of Inner Vane of Bird Bioloa'f I

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J.J6 Figure 3-1 3 Modified Contour Feath e r s of Black Crowned-Crane: The disti n cti v e crown of rhis l a r!je A frican bir d is fo rm e d f r o m stiffe n e d s tra w /ik e t:OiliO Ur tenlhers. Pho l o m urt esy o ( i l ic h e/ l e BurgessiCLO. Geor9eA. Clark. Jr. but little supporting data exist. I n Willow F l ycatc hers, Conover a nd Miller ( 1980) found that exper i mentally taping down o r removing the bristles d i d not affect the birds success i n cap turing insects. By using a w ind tunne l however, these researchers demonstr a ted that bristles protect the eyes from fly in g insects and other debris. They r e leased par ticles in f ront of the m ouths of Willow F lycatchers and found that more p a rticles struck t h e eyes of birds whose rictal bristles had been r e moved. Rictal bristles a r e h ig hl y devel o ped amo n g certai n species (such as puffbirds Neotropkal relatives of kingfishers) that regul arly captur e scal y m ot hs, butterflies and other large, n oxious insects; appar ently the bri s t les protect the face and eyes of these birds from their p rey Oohn W. Fitzpatrick, personal communication ) Ric t a l brist les also may help birds detec t move m e nt s of prey h e l d in the beak, f un ctio nin g I ik e t h e whiske r s of some mammals. Down Feathers Do w n feathers are fluffy and soft, typ ically lacking a rachis. I f present, the rac hi s is always shorter than the l ongest barbs. Because the barbu les lack hooks, each flex i ble barb can wave abo u t glvTng the feathers thei r c h aracteristi c downy appearance (Fig. 3-14b ). D own feathers a r e exce l l ent, lightwe i g ht insulators because the barbs and barbu les form a loose tangle of air pockets. Down feathe r s i nclud e the b o d y downs and the natal d owns. Body downs the down feathers of adults, are most commo n in wate r birds s u c h as p enguins l oo n s petrels, a uks, geese, and d u c k s a s we ll as i n hawks-al l of whom und o ubtedl y benefit from the e xtr a thermal rnsu l ation. Some birds n otab l y the woodpeckers, generall y lack body downs. Man y female wat e rfo wl pluck body downs fro m their bellies to I i n e their nests. Of these, the most fam o u s Ts the Common Eider (see Fig. 4-124a). On islands off coastal Norway, people coll ect the down from nest s during incubation a nd sell it. The harvesters avoid h a rming the b ird s and leave e n o u g h down so t h at the birds wi ll co m e back to nest each summer. Some eiders nest under she lters set up b y the harvesters, and a few even nest und e r the r esidents' h o uses. E i der d ow n clot hin g and bedding i s n otor i o u s l y expen s ive because accum ulatin g just one pou n d r e quires down from 35 t o 40 nests, the down must be gathered by hand, and the s u pply is limi ted. Nevertheless, e iders pro vide the h ighest quality down used Tn jackets and s l eeping bags. Comell LAboratonf

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Chapter 3Form and Function : The Ext:emal Bird Natal downs are present only around the time of hatching. They are prominent on newl y hatched c h ickens and ducklings, giving these birds their soft, fluffy l ook. These first feathers character i stically lack barb ule.s on th e outer portions of the outermost barbs a nd are prob ably important for insulalfon, camouflage, and soda! behavior, as discussed below. Natal downs ar ise from the same follicles that l a ter produce contour feathers, and are typically carried on the tips of the g rowing contour feathers. In contrast body downs of adults arise from follicles that produce only down feathers. The otd sayi ng "naked as a jay bird'' is quite correct for young lays, such as the Blue Jay and Steller s Jay, which have no nata l downs af hatching. The newly hatched young of many other birds, including most passerines, h ave a much-reduced nat al down. Clues from em bryonic development however, indicate that the ancestors of these birds had a co mpl ete coat of natal down. The less down a new nestling has, the more easi l y it is warmed by its parent. Therefore, scientists h y poth esize that naked chicks save energy both by not producing down and by quickly absorbing their parents bod) heat, whkh may allow them to develop mor e quickly. Chicks that leave the nest promptly after hatc hing, such as ducks and pheasants, must carry their own insu l ation from the moment of hatching, and so have kept their down coats (see Fig. 8-113) a b 3 Common J>uon!VI/1 Down Fe.lthl"r Many kinds of young t h at cannot fly for weeks after hatching have an i nsul ating cover of downy feathers th at lasts for much of the flight less period -during which the young grow enor mou sly. Presum ably, it is most efficient to postpone development of contour feat h ers until the bird requires them for flight. Hawks for examp le, have a prolonged downy c over in early life. Their coat of natal down is followed by a second downy plumage, consistingofbody downs, which transforms th e appearance of the young (fig. 3-15). The grad u a l replacement of natal downs with darker body downs, and eventuully w ith Juvena l contou r feathers makes these hawk nestlings look like c c l ean, w h ite snowmen, growing increasing l y dirty and angular in t h e winter's afternoon sun. Semi plumes The semiplumes ( Fi g. 3-14c) occur in a continuum of forms be tween down and contour feathers. Unlike contour feathers, t h e bar buies lack hooks a nd thus the barbs do not cling together as a vane but unlike down feathers, the rachis is longer than the longest barb They lie at the edges of the contour feather tracts someti m es visible, sometimes hidden beneath the con tour feathers. Semiplumes provide insu l ation and help maintain the streamlined form in the overlying feathers, func tioning much like tissue paper stuffed into a pa i r of good shoes that are not being worn. Filoplume s Scatte r ed amo ng and usually hidden by the contou r feather s of most kinds of birds are feathers of a third major type known as filo pfumes. Hairlike but relatively stiff, filop l umes are simp l e struct ures-a of Bird Figure 3-14. Specialized Feathers: a : Rictallnistle < on a Common Poorwi/1 .mel from .Jn Arn(ft'ican Robin. b : Down Feather. c: Se.miplume. d; Filoplum e Drawings b c;, and rl Chi!rles 1 Ripper I

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318 Figure 3-15. Nestling Red-tailed H awk in Second Coat of Down: In h,1wks, rhe n a ral down is fu/luwedb) il coa r of bod) down that insulates them during much o f rl!eir long nestlinM stage. Photo co llrtesy of l im Wea1er/CLO. Figure J-16. Typical Powder Down Feather frum a Pigeon: Adilp t ed from Luc,J.s and Srettenheim ( 1972. p. 337, Fig.l27C/. P o w d e r D owns rachis, usu ally bare, with barbs if a ny, onl y on the tip ( fi g 3-14d). These a r e the hairs" that you see on a plucked supermar k et chicken. U n like con tour feathers and body downs, fila p l umes l ack feat hermu scles.They do however have sensory receptors i n the s kin next to their follicles, whi ch moni tor moveme n t w i thin the feather coat ( Nec k er 1 985). Why are such receptors necessary? Fully g rown feathers are dead str u ctures analogo u s to huma n hair and fingernails; therefo re, much or a bird's body is covered by a fle>
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C hapter 3 Form and Fundion: The External Bird its bi ll s moothing the barbs so that the y will lock to get her. The bir d fluffs the feathers in th e sec tion of the body it is preen i ng and turns a nd twi s t s i n a variety of movements wh ich-if one follows the m close l y-are all qu i te ster eotyped, a bou t the same for each part of t he body and each f eat her every time. Preening keeps the feathers neat preserving the i r st reamlini n g a nd insulating effects as wel l as their col o r p atte rn. Preening also r emoves external parasites ( ectoparasites), some of whi ch ar e described below. B irds preen even without sensory stim ulation from the regio n be ing preened, as s hown b y expe rim e nt s in which severing sen sory nerves from certa in skin areas did not eliminate preen i ng of those areas ( Deli us 1988) Thus, p r ee n i ng a nd perhaps other grooming behaviors a r e pra c ticed even in the abse nce of a "ti ckle" or o th er st i mula t i on of th e s k i n T h e advantage of this kind of unstimulated p r ee ning ma y be that the b ird r o u tine l y cleans and sort s through its feat h e rs, r e moving ec toparasites and other d istur bances in the feat her c oat before they become problematic ther eby i mproving the coat s overall san ita tion and hea l th. Althoug h resear c h e r s have not examined close l y th e seasonal frequency of g rooming behaviors for man y bird s t empe r a t e-zon e birds do appea r to groom less i n the colder months. Dur i ng sho rt winter days, s mall birds must spend much of their time fo r ag in g to get e n o u gh to eat so the y have less time to groom. Fur thermore b eca use ectoparasitic insects and mites are cold-blooded (ectoth er m i c), they are presumably less likely to moveontoorbetween hosts w h e n it' s cold. We would expect birds in tropical regi ons w i th little season a l c h a n ge to have more uniform grooming p a tterns, but thi s a pparentl y has not b ee n investigated. As yo u might expect, birds groom more often when they are molt in g A lso, b irds that h ave s p e nt the night incubat i ng eggs ( for example, female passerines ) o f t e n e ngage in a prolonged bout of preening j ust afte r l eavi n g the nest for the first time each morning If you observ e thi s hehav i o r yo u know you' r e watch i ng a n incubating bird. Certain kind s of bird s with strong socia l ties s u c h as parrots a nd crows, a r e w ell known for their allopreening, in whi c h one bird pre e n s a n o ther. Bird s ofte n direc t their allopreening to the back of th e n eck a nd o ther areas that the recipient canno t reac h with its own bill. Allopreen in g presumabl y helps to remove ectop a rasites to keep the plumage i n orde r a nd t o est ab lish and enhance soc ial bonds between birds A ll opreening a lso serves as a n indication of dominance-subo r dinance relation ships, as s ubordinate i ndividuals offer themselves to of Bird 319 Figure 3-17. American Oystercatcher Preening: Wl1en 11 bird gr11s p s a feather near its base, then nibbles do w n tfl e sflaft toward th e lip, r emoving s tal e oi l a n d d i rt. Photo by Brian Kenney.

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3-20 Figur e 3-18. Oil Gland o f H a nd -Held Blue Jay: B y carefvll y the f e
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Cl1apter 3Fonu and Function: The Et.temal Bird one of the two techniques, but some birds such as Blue Jays, use bot h methods. Why differe n t birds use d i fferent headscratchin g m ethods is n o t known so a good research opportunity for a dedicated birder e:>:ists a here. Birds that can't scratch their heads, e ither through ac c id e ntal f njur[es o r exper i m e ntal use of n eck co ll a rs, tend to have moreectoparasites livin g o n their head s (Clayton 1 991). Bathin9 b Another feat h er main(ena n ce behavior is b at hing. Bird s may bathe in wat e r s n ow o r even d ust. In wa ter, the manner of bathin g t e nds to be quite consiste n t wi thin various families. Swallows and swift s drop do w n repeatedl y and s kim the surface of a lake, pond or stream to wet their feather.\. Terns p l u nge i nt o the water from t h e a ir, and kin g-fishers, from a n overhangi n g branch. Many fo rest birds bathe in rainwater or dew t hat has coll ected on leaves. Most songbird s such as American Robins and E uropean Starlingsstand o r squat i n s h a llow pudd les, vigorously rufflin g t h e feathers and s hak in g both wings, creat in g a veritable shower Hummingbirds sometimes d a rt in <1nd o u t and swin g back and forth i n the spray from a garden hose o n a hot day. Common Nighthawks may bathe on the wing during int e nse downpours a lternatel y f lappin g rapidly and ruffling the body feathe r s amid the deluge. A thorough l ywetbird can be q uit e h elp less, and m a n y are unable t o il y eff i cie n t ly, m ak i n g them p a rti c u l arly v ulnera. b leto cats a n d other predators Because birds must dry as soon as possible all have special d ryi n g m ove m ents. After bathing a bird typically s hakes i t s body to t hrow off extra water, wh ir s the w ings, f l uffs its feather s to promote evaporatio n and begins t o preen and scratch its head. Similar body motions a r e used i n snow. Durin g hot weathe r ; bathin g in water might help a bird's body temperature to stay down. Dust-bathing i s most often r e p orte d for s pecies that spend much time o n t h e ground, such as House Spurr ows and Wi l d Turkeys. This beh avior i s not a s ub stitute for water bathing; several families of bi rds do both In dust-bat hin g (Fig. 3-20), a bird usu ally squats or lies down in a dusty area, ofte n il dirt roacl, and drives fine par t icles t hroug h its p lumage by r o ll in g lis body, fluff ing its feathers, w iping wlth i t s head and b i ll or even, in the manner of the Great e r Rhea of South America, picki n g up dus t and throwing it over its body. n1e bird removes 5ome o f the dust by v i o l e nt shaking, b u t often much dust remains, sl. aining the bird's p lumage the c olor of the soli. H and book of' Bird 3 Figur e 3-19 H ead-Scra tch ing M e /hods: /Jinls scratch their heads either by ( a ) bringing the leg under the wing, as Tn nr( b ) over I he wing, as in many tyr.mnid flycatchers. Most spectes use only o n e oi rile rwo I

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3-22 Figure 3 -20. Wild Turkey Dust-Bathing: L yiilg itt the dust, a dust-bathing bird to/Is and wiggles Its body to work the dirt into its feathers, tossing dus r up over back using its bill or wings. Photo by Sandy Porlulka. Georae A Clark, Jr Presumably all kinds of bathi n g can hel p to con tro l ectoparasites, but th i s has not been s tudi ed ex peri mentally. Ectopara sites breathe th r o u g h small holes in their outer skeletons, which a r e vulnerable to clogging with dust. Compar i ng birds with and without oppor tun i t ies for dust-bath ing has s hown that dust -b athing h e l ps to remove substiilnces coati n g the feathers such as o l d oil gland secretions. SunnintJ Sunning may also help mainta i n the feathers (Simmons 1986) Sunn ing birds adopt quite var i ed and extre m ely unusua l postures Commonly the bir d's feathers are fluffed th e tai l is sp r ead against the g r ound, and a wing is extended on at least one side, somet i mes bot h. Sunning birds frequently lie on t h e g round in a wa rm place, with the head lowered and tipped to the s ide, remaining nearly motionless for many seconds or m inutes. Although sunning has been descr i bed for n umer ous species of birds, few experi men tal studies have tested its functions. S u ggested purposes include condi tionin g the feathers by keep in g them supp l e through limited heating; harming o r r eposit ioning ectopara sites; and savi n g e n ergy by ta king up solar h eat th rough the feathe r coa t. Thepossibilrty that birds might sun simp l y because i t feel s good is d i fficu It to test. A n umber of l arge birds including cormora nts, anhingas, pel icans, sto rks, and New World vu l tures stand for many moments with their wings extended to the side in a pose known as the s pread-wing po sture (fig. 3-21). A l thoug h co rm orants and anhingas are closely related, they use the sp r ead -wing postures in slightl y diffe r ent ways. Both types of birds prey on f ish, but th e feathers of anh ingas are more permeable t o water. Thi s r educes th e b i rds buoyancy a nd allows them to swim for long periods with just their necks and heads above the surface Both cormorants and anhi ngas use the spread -win g posture to dry their feathers afte r swimming butanhi ngas take l onger to dry beca u se their permeable feat hers take up extra water. Furth ermo re, anhi n gasgenerale less heat interna l ly, and in cooler a reas, they may use the spread-wi n g posture to abso rb sun li g ht. The difference i n anh in ga and cormora n t energy production is r eflected in the i r geogra phi c distributions-cor morants can live in much cooler r eg i ons th an can anh ingas. AntintJ Like bathing a nd sunning, anling i s believed to help contr o l ectoparasites. In passive anting a bird simply statio n s itse l f among a swarm of ants, perm i tt in g th em to run a ll over its b ody a nd move in and out among the feathe r s ( Fig. 3 22 ). In active anting a bird picks Cornell L.aboraton1 ofOmitholoatf

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up an ant or other che mi ca l l y potent object, s u c h as a millipede, a nd deliberately rubs i t in the feathers Objects rubbed i n the feathe r s dur in g "anting" ( i n its bro ad sense) i n clude insects, p l ant mater i al, an d even ciga r e tt e butts. Ornithol ogists presume that the rubbed mater i als con tai n c h e mical s that are n ox ious to ectopa r asites. B eca use birds somet i mes eat t h e a r thropods used i n ant i ng, it's possible that t h e process also h e l ps r i d a potentia l food item of its most noxious che mical protection Ectoparasites Co n tro llin g ecto parasites is i mportant t o a b ird' s fit ness. Although car ry i ng a few ectopa rasites ma y have littl e effect o n a b i r d a h eavy ectoparasite load can impair a bird's health and rep rodu c ti o n. Sci entis t s believe t h a t ma n y feather-mai n tenance b ehavio r s evo l ved t o control these parasites, e i t h er physicallyorchem ica ll y Many birds, i n clud in g hawks, House Sparrows and E u ropean Star l ings, ad d pi eces o f fresh plants to thei r nests after they complet e H andbook of Bird BioloB'f Figure 3 -21.Anhinga Drying Wings: See text for explanation. Photo courtesy of lsidor Jeklin!CLO Figure 3 22. Blue ja y Passivel y Anting: In passive anling, .a bird squats among a group of ants with its wing 1.1ncl some limes tail ) tearl1ers spread, and lers the ants run in i!nd out of the feathers and over its body. Anting is thought to help in rhecontrol ofectoparasites but is nol well understood. Drawing by Charles I . Ripper.

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3 Geor, A Clark, Jr construction Some of these plants either produce noxious to ectoparasites, or have antibacterial effects. Clark and Mason (1985; 1988 ) found that at least one bird, the European Starling, appears to choose plants specifically for these properties Birds are host to many kinds of bloodsucking external parasites, especially flies, ticks fleas, lice, and mites. The habits and life histories of these parasites are fascinating, although in many cases they remain poorly studied. Many ground-nesting birds carry the same species of ticks found on mammals in the same habitat i the Ruffed Grouse, for example is ofte h heavily infested with rabbit ticks. In North America certain birds especially those that frequent the ground, may carry the tick s that sometimes contain bacteria that produce Lyme disease, a serious human health problem. Another group of ectoparasites that feeds on the blood of mature birds is the hippoboscid flies, which superficially resemble house flies but are vertically flattened so they can slip readily between the contour feathers (Fig. 3-23a ). Nestlings, especially those ofTree Swallows, bluebirds, and other cavity nester.s, often are infested with the large larvae of another type of (ly called a blowfly, which feed on their blood (Fig. 3-2 3 b ). Bird I ice ofthe order Mallophaga feed on feathers and the surface layers of the skin ( fig 3-23c). Quite harmless to humans, a few species do live on mammals, feeding on hair. Many are highly hostspecific ; that is, a given species of louse lives only on members of a single family or genus of birds. Like the hippoboscid flies, most bird lice are flat, and live among the feathers. Most s pecies are adapted for life on specific portions of a bird's plumage, rarely venturing away from the head, neck body plumage, flight feathers, or whatever area the louse calls home One very specialized genus of lice lives in the throat pouches of pelicans and cormorants. Several kinds of mites occur on birds including itch-mites, nasal mites, and red mites. The most specialized are tiny feather mites that live among, on, or even with i n the feathers, feeding on the feather itself or on the skin {Fig. 3-23d ). Some are so specialized that they live only in certain areas of plumage on certain species; one mite species, for example, lfves only on the white areas of the remiges of the Eurasian Nightjar. Feathers prov tde some protection against nonparasitic biting insects, such as mosquitoes. Mosquitoes can often get a blood meal, h0wever, by biting where the feathers are short such as around the eyelid, base of the beak, or on the legs. Mosquitoes can transmit encephalitis viruses to birds, and they sometimes carry these viruses from birds to people. I n humans, the disease can be fatal ; fortunately it is uncommon. Different k inds of birds differ in their resistance to b i ting mosquitoes Active birds such as Whi te Ibises move constantly and so are less likely to be bitten than relative l y s luggish birds such as Black crowned Night Herons. Most insect bites, however occur at night while birds are roosting Cornell of Ornitholoalf

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Chapter 3-Form and Function: The External Bird a H ippo bo scid Fly b. 8 /owflr Lanlae on Nestling East ern B l u ebird IJ/owlly Larvae 3-25 c. B ird Louse d Fea ther M ite Figure 3..,23. Avian Ectoparasites: a; Hippoboscid fly. Note extremely flattened body that allows iltoerawl contour feathers. Hippoboscids, also called # feather-flies/ are bloodsuckers that live on m-any different species of bird!;, especially birds of pre y b : Nescling Eastern Bluebird with two au ached blowfly larvae. These are particularl y common o n of .:avl/ y-nesting birds. c : Bird louse ( Order Mallophagil) from a turkey. These ectoparasites are also fhmened, a11d the y ieed on bitd feathers and skin d: Feacher mite from a passerine bird. Mites live a mons-on, or wit/lin the feathers. feeding on feathers dtld skin. Illustr ations are not drawn to scale. Drawings c and d by Charles L. Ripper. H andbook of Bird Bioloelf

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3 Development of Feathers 8 The skin of a bird, like our own, consist's of two major parts, the in ner dermis and the outer epidermis. Throughout life, the epidermis continually renews itself by the growth of new cells in llslower layers and the hardening, drying and s l oughingoffoftheoute rlayers. During embryonic development, t h e surface of the skin i s covered with l ittle bumps known as papillae (Fig. 3-24a) arranged in the eventual pattern of the bird's feathers. Each papilla is an outgrowth of dermis forming a core beneath a rapidly multip l ying layer of epidermal cells. As the proliferation ofepldermal cells continues, o utstrip ping the dermis, the epidermis doubles inward around the papilla forming an epidermis lined pit the follicle (Fig. 3-24b). From each follicle a succession of feathers is produced by the bird during its lifetime. As the epidermal cells multip l y the papill a elongates into a cone. The outer cell s harden, fuse, and form an epidermal collar thaf surrounds the dermal portion of the original papilla ( fig. 3-24c). Most conspicuous structures in the fully formed feath er o r iginate in this epidermal co llar The inner layers of the collar co ntinu e to grow toward the center forming a tubular series of ridges that eventually soli dify to become the rachis and barbs of the feather. Because the feather grows from its base outward, the outer part is always the o ldest, as in a hu man fingernail. The dermal portion of the papilla remains in the fo lli cle for the l ife of the bird. While each feather is developing, blood vessels extend outward f r om the papilla into the feather shaft. providing a temporary source of nourishment for the growing feather_ When the feather is fully formed, the b l ood supp l y is c utoff as the vessels are resorbed Into the papi II a through a hole at t h e very end of the calamus. On large feathers, you can see this hole with the naked eye, a lthou gh it appears more as a depression than a hole. A growing feather i s surrounded by a thin feather s heath which acts somewhat l ike a mailing tube (fig. 3-24d) When the sheath breaks open, the feather vanes unfurl from the tubular packing into the broad, mature feathe r The unfur ling occur s s l ow l y over many days. Packaging feathers in sheaths permi t s them to grow muc h more densely than they cou l d if each feath er someh ow emerged full y unfolded di rectly from the skin. Growing feathers can be recognized by the intactsheaths, which are typically gray or bluish, and look I ike the fat tips of knitt ing needles sticking out of a bird's skin (fig. 3-2 5). Before the sheath s open, these growi n g feathers are termed pin feathers Look for a pin feather on a supermarket chicken, and break it open. Notice that the material inside is soft and moist. This is the developing feather; on a live bird the cells would be alive and mul tiplyi ng. As the feather g rows, its cells eventually die and become hardened as the sheath splits and falls away. In many cases the oute r (distal ) portion of the sheath dies and breaks open, while growt h cont inues in the parts of the feather still in the s heath. Com ell of OrnitholofJLI

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Chapter 3FOrm and Function : The External Bird a b Follicle d Feather Sheath Feather Papilla I Blood Vessels juvenal Feather Delit'loping Feathrr---RI .' 3 Figure S-24. of a Feat her : a : The skin with a feather papilla beginning t o form. b :As eptderrniJI cells multiply more quickly than dermal cells, the epidermis folds Inward around the papilla, forming an pit, the follicle. cAs epi dermal cells continue to multiply, the papilla elongates to fcxm a cone or p i n feather."The dermis remains as the dermal papill at the base of the developing feather, and is surrounded by a collar of epidermal cells that multipl y to produce most structures in the developing feather, including the thin feath e r s heath and a series oi doughnut-shaped ridges that eventually form the barbs and rac his. The growing feather is nourished via blood vessels that exteod into the shaft. d : The feather sheath grildually splits open from the tip and falls away, allowing the feather vanes to begin unfurling. In this case a juvenal feather has developed and cdrries out the ofd natal d own on its tip. Drawings d1 b and d b y Charles L. Ripper. Handbook of Bird Bcolo8'1 I

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3-28 Figvre 3-25. Nestling ;,, Pin-Fea the r .Stage: With eac h developing feathflf still c ompletf'l )' cmc/osed In sheath. a )IQung l?irci i n the p i n -feat/)er stage looks s nmerhlng /Ike a small porcupine or pin-cushion. GeorBe A. Clark.. Jr. When feather development Is completed, t h e ce lt s cease to multiply. Yet the or i gina l papilla w ith its dermal core and covering, waits deep within t h e follrcle, ready to rest art the process when i t is time for a n ew feat her. Then a new collar, growing upward a nd o u tward, w i l l push out (he old feather. The harde n i n g of a maturing feather fs ca used by formatio n of the p r otein keratin, a metabolic prod uct of the dying ce lls. Indeed, keratin is t h e pr i mary struct ur al componen1 of mature feathers. Originally produced Inside cells, the keratin f r om one ce ll may bond stro n gly with the keratin i n adjoini n g ce lls, developing over time into s u c h familiar structures as scales, claws, and feathers. Avian kerat in s differ in t h eir ami no acid sequences from all othe r known keratins, including t hose in the scales of li ving repti les such as lizards and croco d iles, a n d in t h e nails and h air oi hu mans. Therefore cheevolution of feathers must have in volved maJor evolutionary in n ovat ions (Brush 1993 ) Keratin s are not r eadily digested by any of the chem ical s ordinarily found in t h e digestive tracts of animals, so feathers last lon ger t han most other disca rded animal parts. But we are n ot chest-deep in loose f eathers, even though birds drop billions of feathers annually during molts, so thei r keratin is broken down somehow. Researchers assume that bacteria and f un g i are responsible, but a lmost nothing is known about the specific organisms that d igest feathers in nature. Man y enviro nmental factors can the d evelo pm e nt of feather structure. for examp le, nutr i t i onal deficiencies can lead to minor changes in bar b ule s tructure ( Murphy et al. 1.989). This infor mation is useful to researchers in the f i e l d. For species that periodica ll y can be recap tured researchers can p lu ck feathers and then, when the bird is captured again examine the struct ur e of the r egrown feather to determine t h e bi rd's nutritional state (Grub b 1995). Molts and. Pluma9es A feather is a dead structure; it cannot be repaired if it becomes worn or broken. Yet the feathers of mosr birds especially those livi n g i n open, sandy, or grassy areas, become brittle, faded, and frayed in just a few months. T o restore their feather coats a n d produce fea(hers app r opr iate to the ir age and sex, birds regularly must grow new sets oi feat hers. Replacing all or part of the feathe r coat Ts called molt i n g In a complet e m o lf all feat hers are replaced; i n a partiaJ m o lt on l y some feat hers a r e replaced. I f an ent i re feather is lost b etwee n molts, it g rows back r ight away. Damaged, broken or worn feathers are repl aced only during the regular mo l t cycle, however. Com ell of Ornitholo&l1

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Chapter 3 For111 and Function: The Exterrral Bird During a tyrica l molt, growth of a new feather push es the o l d o n e from it s follicle. In juvenile birds each natal down feather may b e phys i ca ll y att ac hed t o t h e tip cjf its s u ccesso r th e juve n a l feat her, w h ich is the fi r s t true contour feath er; thu s the new juven al feather carr ies th e o ld nata l down o ut as it g rows (see Fig 3 24d). ( N ote tha t the term juvena l is applie d to feathe r s and plum ages, w h e reas "juvenile" desi g nates a young bird; the two word s ofte n a r e confused. )The str eng th of the co nn ection h etween the downs and the contour feat h e r s varies great ly. In some birds, t h e down i s so d elica te that it br eaks at the merest touch and f i nding museum s pe c imen s that s how the co nn ectio n can be difficult-the down has bro ken off e ith er in the nest or during the prepa r at i on of the speci m en. I n othe r birds s u r h as the Eur opea n Starlin g a n d American Robin the connecti on is v ery s trong a nd yo u ca n often see the fluffy natal dow n s s till attached t o t h e head s o f juve ni les who h ave recently l eft the i r nest s ( f i g. 3-26). Because produ c in g new feat h e r s takes a lot oi energy birds ge n er a ll y molt w h e n they are not e n gaged i n oth e r e n e r get i ca ll y d ema n ding activities, s uch as feed in g young or migr a ting. The m o lting pr ocess also r e duces flight efficie ncy, lowerin g a bird's ability to eva d e predators and procure food. Therefore, l o n g -di s tan ce mig r a nts m ay mo l t before t h ey migrate, after they mig rate, or part l y befor e and partl y after. I n the temperate zone, ad ults of m a n y species of North A m erica n so n gbi rd s molt durin g l ate summe r when th ey a r e n o long e r car i ng fo r young bur before fa II migration. Because t e m peratures a r e often s till warm a nd en e rgy demands are r e lative l y low, th i s is a goo d lime to mol t We humans n otice this m oll w hen su m e of our m o r e colorfu l birds acq u i r e thefr subdu ed winter I ones: m a l e Scarlet T anagers b eco m e yellow-green; the bright red head of mal e Weste rn Tanager s becomes yellow; and ma n y str iki ng mal e warb l e rs, such as I h e C hest nul-sld e d Warh ler, Yel low-rumpe d Wa rb ler Magnol i a Warb l e r and Co rnman Yellowthroat. l ose their bold s prin g patte rns. Annual Molt and Wear CLfcles Bird s va r y grea tl y from spec ies t o s p ec ies in t h e number, type, and timi n g of their m olts. Some birds, s u c h as A m erica n C r ows, un dergo o nl y o n e complete molt per yea r M ature crows look mu ch the same before a n d af terthls a nnual m olt; the new fea th e r s are less worn th an th e old o n es, but this is eviden t only a t clos e quarters. Many othe r North America n pass e rines s u c h as th e Ameri can G o ldfinch, unde rgo a complete molt followin g th e bre ed in g seaso n and then a partial molt i n winte r or spri n g Thi s par tial m o lt i ncludes a l l t h e co n tour feat h e r s e x cep t those of the win gs and tail, a nd p rov i des h r i ghte rcolors f o r the breed in g seaso n Only a few species are known to h ave two compl ete mol t s per year Most of these I i ve in har sh hab itats that qui c kl y wear ou l feath ers. Examp les include Mars h Wrens .1nd Bobolinks, which move within abrasive vegetation and African H andbook of Bird Biolo[ill 3 Figure 3 26. Fle dglin g Eastern Bluebird: Note down teillhers still .1/t,?Ched to the h ead ulthis ne.vll tledgecl hire/. Phnto murtesy o/ t!Je North llmenc;w Bluebird Socil!l) I

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3-.:m a c Figure 3 2 7. Tire Effect of Wear on Eumpe.1n Starling Feathers: a: Aftet tlw t.t/1 molt, lk"l>l) /!ffi\VIl Fumpean <;t,lt'litW IJnd1 lcutl) lip> of th< it,, /,!// te.llhe r s give I t c: 6 1 sprin g the fl"illlf'fl. hoft\ It ,, h.Ivc 1\' IJI'IIOft, t tllllthc ,t,tt'linl! ,/ Mlo>!O) P h111 0s ,,
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Chapter 3Form and Function: Th e Extemal Bird Third Winl(lr ( Third Baste:) Ft'rst Winter (First Basic) 3-31 Figure 3-28. C ompl ete Plumage S erie s of the (;u/1: Some birds take more than one )tear to reach their definitive adul t plumage After shedditJg its nalill down, the Herring Cull passes through four different subadult plumages b e lor e reaching the r:1miliar while and gm)' definitive plumage of the adult--at four years oi agel Han dbook of B i r d

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GenraeA. Clari.,Jr. l ong as seven or eig ht years to reach their definitive p lumage. Gfven a choice, many birds such as g ull s select mate s in definitive plumage Sometimes, however b irds in s u badult plumage do get a c hance to breed. Breeding by subadults occurs prin c ipall y among species with relative l y short l ife spans, o r when birds in definitive plumage are i h short supply. In some species, one sex remain s in subaJuh plumage for longer than the other, a s ituat ion termed delayed plumage maturation. TI1e mal e Amer ican Redstart, fo r insrance, does not wear h i s o r ange-and black Jefinit ive b r eeding plumage until his second breeding season; his firstbreeding p nearly identicalto that ofth e adult female, who has yell owish patches, and who acqu ires her definitive p l umage by her fir s t breedin g season. H oweve r at least some mal e redstarts b reed at one year of age, despi t e their subad ul t p lumage. Why plum age matura t ion is delayed i n this species is not known (Morse 1989); the trait is not shared by most other New Wor l d warblers. How d elayed p lumage maturation evolved; and the advantages it brings is a h ot topic of research among o rnith o logicSts. A number of hypO'theses have been p roposed to explain why one sex ( usually the male ) mi g h t r e m a i n in subadul t plumage longer than the other. The "female mimi cry" h ypothesis ( Rohweretal. 1 980) s uggests that dur ing the breeding season subadult males may be abl e to fool adul t male s by mimi cking females. Thus disgu ised, the subadults may b e abl e to de fend their own terr itories or may g<1in access t o adul t territor ies, thereby procu r ing mor e iood resources, or even mating with the adult femal e w h ile her mate i s away. I n contrast", the "status signall ing" h ypothes i s ( McDonald 1989) suggests thatsubaclult plumages acc ur ately co nvey a male's younge r age to adults, thus decreasing the amount of aggresSion it receives from o lder, more dom in a nt males. This h ypothesis is mostrelevanttospedes such asl.o n g-tailed Manakins (see Fig. with well-developed age hierarchies i n which younger males rarely mate1 and i n whic h a dull males have e lab orate p lumages or behaviors that are energetic a ll y costly to main tain. Othe r h ypot heses focus on potentia l advantages conveyed by subadul t plumages in w inter. For instance, Butc he r a nd Rohwer (1988) proposed thal subaclu lt plumages may eithe r decrease a bi rd's co n Spicuo usness to predators ( the "win ter crypsis" h ypot hesis) o r may de c rease male-male aggression (the wi n ter status signalling" hypothes is). In e i ther case, subadults might enjoy higher winter surviva l rates. Butcher and Rohwer s uggested that although the advantages are gained in winter, bi rds m i g ht retain thei r subadult p lumage through the breeding season to avoid the hig h en ergeti c costs of spr ing m olt. (Most birds undergo the i r most exte nsive molt in fall.) Undoubted ly, different species gain different advantages from delayed p lumage maturat i on, but researc hers attempti n g to de t erm ine wh ich hypotheses apply to whi c h bird species have met w ith mixed success, Thewillingnessoffemale birds"of-paradise to mate with males in s ubadult plumage when males i n def i n i t ive plumage are not availab l e may have saved some species of these beautiful birds. Du r ing the early 201 h century, feathers of wild birds we r e i n great demand for deco r ating o(Omitholva'l

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Chapter 3 Form anJ. Functiott; Tlte Bird wome n s hats-a practice no l o nger fashi o nabl e and now banned in m a n y p laces. I n New Gu inea, f or example, killing male birds -of paradise in their spectac u lar definitive plumages (see Fig. 3-1 0) was so extensiv e that these m a les we r e nearly extirpated from accessible a reas. Ordin ari ly, f e ma les do n o t mate with males i n thedu ll ers ubadu lt plumages, butthey had to when m a les in d efi nitive plumage becam e fn s h ort s upply. plumage maturation of young males therefore proved fortuitous ; otherwise, the feath e r tr a d e might have co mpl etely wiped out som e of the show iest bird species i n the wor l d. Pluma9e Namin9 SLfstems In it s broadest sense, a plumage is a bird's e n t ire feather coat; thus, you might say, "The plum ageoft h eAmerican Robin isora n gea ndgray." Some autho rities, however, use the word to designat e the set of feathers producecl in a particul a r m o lt. In this usage, after a p artial molt, a b i rtl simult a neously wear s parts of two d i ffere nt p lumages. I n t his chapter we wi ll use the former definit ion and ref e r to the bird's ent ir e feather coat as its pl umage. Historically, the com m o n practice was tu name plumages for the presumed presence o r absence o f breedl n g act ivil y at the t t me I h e bl rd wore the particular plumage Thus, i n spri11g and s um mer bird s were said t o be in nuptial ( b reeding) plumage a nd in fall and winter, in postnuptia l orwint er plumage. Thi s system was som ew h at m1sl eading, however because different plumages a r e not necessar ily lin ked with r e produ c tiv e activitiesorseasonsofthe year. A m ong bi rds i n t h e tropics, w h e r e there is n o real winter, winte r plumages may becorre i
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I Winter ( Basic) Plumage Figure 3-29. Scarlet Tanager: The adult male Scarlet Tanager alternates betWeen a brilliiJnt red breeding plumage and a dull yellow-green plumage during rhe nonbreeding seasvn. Tile wings and tail remain bi
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Chapte r 3-Form and Function: The External Bird 3-35 Table 3-1. P l u ma g e Nami n g Sytems TRA DITIO NAL SYS TEM H U M PHREY-PA RKES S YSTEM NATAL DowN ( I F ANY) NATAL DOWN ( IF ANY) Postnat al Mol t Prejuvena l Molt j UVENAL P LUMAGE j UVENAL P LUMAGE Postjuvenal Mol t 1st P r ebasic Molt I 1 sT W INTER P LUMAGE 1sT BASIC PLUMAGE 1st Prenuptial Mol t 1st Prealternate Molt 1ST NUPTIAL P LUMAGE 1sT ALTERNATE P LUMAGE 1st Postnuptial Molt 2nd Prebasic Molt 2ND W INTER P LUMAGE 2ND BASI C P LUMAGE 2nd Prenuptial Mol t 2nd P r ealterna t e Molt 2ND NUPTIA L P LUMAGE 2ND ALTERNATE P LUMAGE 2nd Postnuptial Molt 3 r d Prebasic Molt 3RD W INTER P LUMAGE 3RD BASI C P LUMAGE When a bird reaches its definitive plumage, umerica l designations a r e dropped. For this example, we assume definitive p l umage i s r ed afte r t he 3rd w i n t er o r 3rd basi c plumage: Prenuptial Mol t Preal ternate Molt NUPTIAL P LUMAGE ALTERNATE P LUMAGE Postnuptial Molt Prebasic Melt W INTER P LUMAGE BASI C P LUMAGE ETC. E TC. Handbook of Bird Biolo911

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3 Male-Breedtng ( Alternat e) F igure 3 30 Malla rd Pl u mages: The male Mallard in ec lipse phtmage looks remarkab/>' like the female but his bill islighl olive gr een wheretrs the f e male's bill is omnge marAed with il/Jck 1he basic plumage of the female Is iderttical to l1er alternate / breeding ) pluma}:!e. Female-Bmedin g !t\lte mat e/ Male-Eclipse / Busi c) ln any particul ar tract on l y a minority of feathers are replaced at one time (fig. 3 3 1 ). Thus, you will ra.rel y see a land bird missing more than a few wing or tail feathers This gradual replacement of feathers spreads out I he energetic cost of mol t i ng over time, while minimally impai r ing the fli ght insu l a t ion, ilnd other func t ions of the feathers In woodpeckers, for example, the stiffened rect rlces act as a prop to support the bird w h ile i t searches up 3nd down tree trun ks. Molting of these feat h e r s star t s with t h e second innermost rectrices and progresses to t'he outside. The long cen tr al pair of rectr ices is replaced only after the other tai l feathe r s have grown in, so the tai l can serve as a sturdy brace throughout the molt cycle. Many wa t er birds incl u ding loons grebes anhingas, swans geese, ducks, and evan dippers, drop all rhe remiges simult a neous l y l eavi n g the birds unab l e to fly d u ri n g their prebasic molt T hese water birds typ i cally have a high ratio of body mass to wing area; t hus the loss of a sma ll amount of w i ng surface area woul d seriously impa i r flight performance. By replacing all the major wing feathers at once, t h ey avoid Lhe prolonged period of impaired flight that wou l d result if the remiges were rep l a c ed gradua lly. Being completely i l ightless for Cornell of Omitholo[jlf

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Chapter 3 Form and Function: The External Bird Wing 5 I I a time probabl y makes th e s e b i rds more vulnerable to pred a tors but th e y ofte n m oit in secluded p l aces and if they are a ttacked, most c a n esca p e b y swimming u n d e rwater. For m a n y male du cks, recall thatthe preba s i c m o l t in whi c h all the f light feathers a r e l ost p roduces a dull eclipse plumage ; th i s helps them r e main inconspicuous Furthermore, th e m olt i n d u ck s occurs in several stages s uch that th e flig h t feather s ar e retain e d until after the brightly c olored body feathers have be e n r e pla ce d A few groups including pigeo n s parrots and c uckoos replace their tai l feath ers I rr e gularl y I n contra s t, some of the s maller owls, such a s the Northern P ygmy-Owl, the Little Owl, and the Burrowi n g Owl. molt all th e r e ctrices at once. This is also true of some oft he other short tail e d birds-the alcidsand rails-whic h use theirtailsve ry l itt l e in fl ying. Simu l tane ous t ail m o l tis most c onspi c uous in the Boat-tailed G r ackle; th e males of thi s long-tailed species appear l udi c rous durin g t h eir s tub-tail e d per i o d. Females o f a number of hornbi ll spe c ies a l so molt abruptl y I n the s e O l d Worl d c av i ty nesters, the fem a les stay in the tree cav i t y throughou t incuba tion and the early part of n e s tlin g life ; w hile sequ e s t e red the y und e rgoa full molt, includi n g an extended flightless period Handbook of Bird 3 Figure3-31 T ypical Progres sio n of Molt in the Flight F eathers: Most b irds m o l r only a few 11/ ghl f eat hers a t o n e time, i n a n orderly pros ressi o n In th e /ilil, th e c entral feath e r s u s u ally a r e l ust f irst and as th ey g row hac k s u ccess ive feath ets toward e a c h side a r e m nlterl. I n this e x ample, th e centra ltd// (eatht:!rs ha ve c o mplet e l y regrow n w h i l e number s 2 and 3 l1ave only partially re g rown T all fearhers 4 a n d 5 h ave n o t yet b ee n molted. In the W in g m olt b egi n s simul tan eous l y i n th e inner pri m.1rles and th e o ut e r secondaries and proceeds i n oppos i te directio ns, as indica.ted b)' th e arro ws. 4 I

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3 Figure 3-32. Male R hinoceros Hornbi/1 Bringing Food to Imprisoned Femal e: During the inc ubation and earl y nest l i n g s t a ges, the femal e hornbi/1 remains s eale d in h e r nesl c a v ity, depending so l e l y on food brought to her b y her mate Photo b y M. Strangt:f\1/REO The birds plaster a mixture of mud and saliva around the ent r ance h ole of the nest, creating a barrier to exclude predators such as climbing snakes and monkeys. The mal e passes all food to the imprisoned female and young through a small opening ; the femal e and young depe nd on his survival fortheir own (Fig. 3-32). Occasiona ll y a bird will shed man y feathers all at once This shock molt or fright molt has been reported for dozens of species in numerous taxonomic families, but occurs on l y in unusual circumstances. For instance a bird may shed its tail feathers when the tail is grabbed by a predator clear l y an adaptive strategy. I t occasiona l ly oc curs during handling by people, and r eports say that it can be induced by vio l ent natural events such as earthquakes and tornados. The me c hanism of shock moll has not been determined, but clearly some r elaxation of the muscles holding each feather shaft must be involved: under normal circumstances, a force of roughly one to two pounds is required to pull out a sin gle feather! The speed of molt varies to some extent with l atitude and the extent of seasonal change in climate Molt 1s often more rapid, for examp l e in Arctic-nesting gulls than i n closely related gull s of the temperate zone. Birds in the Arctic simply do not have time for a slow-paced molt after breeding, as they must soon head south for the winter. The abundance of food and continual daylight for foraging in the Arctic undoubtedly he l p these birds in gather in g the resources they need to molt rapidly. I n some t ropical species on the other hand, molts may be prolonged. The Rufous-collared Sparrow i n northern South America takes two months to molt. Breeding seasons in the tropics also may last a long time, and the energy demands of some species are low enough that they are abl e to overlap molt and b r eeding activity. Once in a while a bird turns up w ith very few feathers on its head. The head may be bare, with the ear opening clear l y visib le, or may have a short l ayer of barely emergi n g feathers. Generall y the enti r e head from the neck up is bare, but sometimes just patches of feathe r s are missing. These "bald" birds (often Blue lays or Northern Cardinals ) a r e seen most often in the fall altho u gh they occasionally appear at other times of the year. Most bald birds seen in fall are probably juve niles born earlier in the year undergoing their first prebasic molt. For unknown reasons, some of these birds drop a ll of the head feathers at one time and quickly regrow them, rather than losing and replacing them a few at a time. Why birds occasiona l ly become bald at othe r times of year, and why adu lt bi rds are somet imes affected, r emain a mystery. It's possible that some type of atypical mo l t causes baldness in these birds o r that a n infestation of feather lice or feather mites is responsible. Whatever the cause, bald birds certainly command the attention of prehistoric vulture-like appearance reminds us of their ancestral ties to reptiles. CornelL Laboratorq of Omitholo8tf

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Chapter 3Form and Function; The External Bird Nonfeathered Areas we now consider par t s of the b ird norma ll y not cove r ed by feathers s u ch as the eyes, bill, legs, and feet. Frequently, their pe culiar.ities in color or form p l ay a sign i ficant ro l e in the bird's life, and a r e usefu l in identifyi n g particLIIar species. E"'es No thorough description of a bi r d is comple t e without mention of the co lor of its iris (see Rg. 3 34c). Although most birds have a dark, commonly brown, iri s around a black pupil1 m any species have more conspkuously co l o r ed irises-white yellow, orange blue, r ed, or even, as in some grebes co ncentric cir cles of two or more colors. The Yellow -eyed jun co and the Red-eye d Vireo are named for the color of the iris in adu lts, as is the Whitebacked Fire-eye of the Neotropics. Iri s color may hel p some birds in spec ies r ecogn i tion. In Malaysia, mixed f l ocks may include several species of bu l bu l s almost ident i cal in size and plumage color, but quite different in eye color-th e dif ferences may help both birds and bird watchers to distinguish among the species! Sometimes the sexes differ in iris co lor. Mature ma l e Brewer's Bla c kbirds h ave a ye llow iris, but fema les have a brown i ris. The effect of iri s color on socia l behavior has not been st udi ed extensive ly, but whe n iris color differs by age or sex it p r esumab l y reflects different social positions and like differences in plumage color, plays a role in social i ntera c tions. Commonly, if the adu l t has a brigh t iris color, the juvenile's iris i s duller, so iris color can indicate the age of a bir d. For example, juvenil e Red-eyed Vir eos have brown irises during their first f a ll. This difference may help the birds recognize ju veniles, especia ll y when there are no obviou s plumage differences. In some species, eye color cont i nues to cha n ge as the bird ages, A Cooper's Hawk begins life with a bright yellow iris, but as the bird grows o l der the eye changes to l ight orange Rhamphotheca then medium orange, 1 h en dark orange, and fi nall y to a deep1 dark red. This pattern of col o r change is so predictable l hat scient ists can de termi n e the bi rd's apprc)xi rna te age by eye co I or a l o n e ( Rosenfield e t al. 1992 ) Bill The t e rms beak and bill are synonymous. Th e visible portion of the bi ll consists of a sheath of skln, the rhamphotheca which cover s the pro j ecting portion of the b ony j aws (Fig. 3 33) .1n most birds, therhamphotheca is hard and hornlike; it is softer and more leathery in most waterfowl, sandpipers p l overs and pigeons. Alth ough the outer l ayers of the rh amp hoth eca cons ist of dead ski n worn away by bi ll-wiping and abrasion during feeding, the in ner l ayers areal i ve and they renew the ou ter cover of sk i n. At the tip, Handbook of' Bird BloloB'I Figure 3-33. BiiiA. n ato my; The premax illa and den t ary bones which make up most of the hard, intemal structure of the bill, are covered by a thin sheath of skin called the rhamphotheca. In mo st birds, the rhamphotheca is hard and hom/ike but it is softer and leathery in most waterfowl. sandpipers plovers and pigeons.

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3 growth is a l most continuous, but h normally is not noticeable because of a continua l wearing away. If an injury breaks one tip o r puts the two jaws out of line, such that one is not worn away by contact with the other, the bill may grow extremely l ong until the bird cannot eat and starves to death. Species that feed on a soft diet of insects in summer and then switch to hard seeds during the cooler months have seasonal differences in bill length. In House Sparrows, for example bills are longer In the summer months and are worn down by the harder foods and grit taken during winter; these differe nces In bill l ength are small and can be detected only by detailed measurements Capt i ve birds may not eat hard enough foods to wear down their bills properly so their owners often give them cuttlefish bone, which p rov ides an abrasive surface to chew on, as well as minerals. In certain kinds of birds, including r atites, albatrosses, pelTels pe l i cans and cormorants, grooves extend along the rhamphotheca In many cases, the function of these grooves is unknown. I n albatrosses and pelicans however the grooves ca rry salty fluids emitted from salt excreting glands near the eyes (see Fig 4-131 }, guiding them from t h e nost r ils to the bill tip, where they drip away (fig. 3-34 a) (These a r e not the types of grooves for which the Groove-billed Ani is named. ) The nostrils or na res (sing ular: n a r is ) are on the upper part of the bil l, usually near its base. The shape of the nares diffe r s a l ong taxo nomic lines The most highly pelagi c order of birds, w h ich includes albatrosses, shea r wa t ers, petrels, storm-petrels, and diving-petrels, i s c hara cte rized by tubular nares ( Fi g 3-34 b} whose function is uncer tain. These birds often called ''tubenoses," excrete larg e amounts of excess salts in a fluid that is released into the nasal cav ities. Some biol ogists believe that the protection afforded b y the tube r educes heat and airflow at the po int where salty fluid i s excreted from the salt g l a nd. Thus evaporation of the salty flu id occurs at a point fart h er down the bill, reducing the possibility that salts left b ehind after evaporat i on will clog the g l and. Another specialization occurs in some ground feeding birds such as starlings, pigeons and domestic c hi cke ns. These birds have a fixed protective f l ap the o p e r culum, partially covering the nares; this ilap may help ke ep out debris ( Fi g. 3-34c}. Perhaps most bizarre are the kiwis of New Zea l and, whose nares are unique l y s ituated at the tip of their l engthy bills (see Fig. 4-54c). Kiwis use their well -developed sense of smell to probe for eart h worms at ni ght. The nares of h awks pigeons and some parrots are located in a l eathery band of ski n known as the ce re, which extends across th e base of the upp er part of the bill and presumably p r otects the nostri l openings (fig 3-34d ). Many land birds, including hummingbirds, woodpeckers, and passer ines, regularly clean their bills by biU-wiping on tree branches the ground, or other surfaces, especially after eati11g messy foods such as oily insects or suet. Other land b i rds, such as doves, rub off debris by scratc hin g wh: h thei r toes and never have been reported to bill-wipe. Ducks and many other water birds dean their bilfs by bathing and rubbing them against th eir feath ers. Cornell L.abomtonf of Omitiloloatt

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Owpter 3Form and Function: The External Bird 3-41 a A lbatross b Iris \ Northern Fulmar d Chicken Red.tailed Hawk Figure 3-3 4.Adaptationsofthe B i ll : a: A groove On each $Ide olthe albatross bill carlieseKCreted sali)' ltwd from the bird' s naris to thetipoftl1ebi/J where it dripHway. b : In the Northern Ft1lmar, likeotherpelagicbird> termed 'tubenoses, a tubularstruc:wre covers the site where salty fluid is excreted (ram the salt gland. The fluid flows lhrough the tube and out the opening in the end These tubular nares may reduce heat and airfi01.V at the salt gland so that evaporation occurs farther down the bill reducing t he possibility that salts/eft behind will clog the gland. c : In somegroundfeeding birds, such as the d.omestic a tl.1p termed the operr:ulum partially covers the nares, probably helping 10 keep out debris. d : M;my parrots, pigeons and birds of pre.y, such iiS this Redtailed 1-/awk> have a leathery band of skin termed the cere at the base oi the bill, inro which the nares open The cere is thought to protect/he nares. Handbook of Bird BioloB!f

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3-42 Figure 3-35. Puffin Beak s : After breed ing pofflns m o lr th e hri8 htl) colored rhamphotheca and their beaks assum e the more subdued tones of the ne w rhampholhecil. Breed in[>! ( Alternate) Bree
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01apter 3-Form nnd Function: The External Bird B il l color also ma y diffe r by sex. In the European Starl ing duri ng breed i ng sea son lhe basal portion of th e lowe r beak be c omes b l uish in males, and pinki sh-brown i n f emales. T h e bill of the Mallard is olive-green to olive-yellow iq the male (varyi n g with the season ) and b right orange mottled with b l ack in t h e fema le. Bil l color mark ingsse r veseveral func1 ions. T h e red mark. on the lower beak of breeding adu l t Herring Gulls is a tar get for beggf n g n est l ings. Whe n the chick pecks at t his spot the a d ul t opens i t s mouth and disgorges food. In t h e n onbreedi n g seaso n this region of t h e bill b eco me s dark. Nest l ing c u c koos, wood peckers, an d passerines have b r ight l y colored tempora r y en l a r gements called oral flanges ( F igs. 3 -36 and 3 -37) at t h e base of t he b i ll whi c h a r e targets fo r adu lts f eeding the young ( Cla r k 1969 ) Juven iles of cavityn est i ng so n gb i rd s such as s tar I ings t ypic all y have bright yellow oral f l anges; these remain visible i n the d i m l i gh t resu l ti n g when a parent b l ocks the nest entra n ce o n returning with food. Co l o r ful bi l l m arki ngs a lso may serve a social fun c tion, especially in some hig h ly grega r ious b i rds such as toucans whi ch have bold, color ful patterns on ove r sized b i l l s Legs and Feet T y pica lly, t he u n feathered part of the l eg is th e lower portion of the tarsometatars u s s imp l y called t h e tars u s by most ornithol ogists. One exception i s t h e Ost rich w h ose e n tire leg, i ncludin g t h e t h igh is featherless. Many b irds have tarsi and feet of g r ay b l ack, or anot her dark color, but o thers show a wide var i ety of co l o r s and p att erns. Bird watch ers often use leg and foot color to r ecogn i ze particu l ar kinds o f birds: the bright yellow legs of t h e Greate r a n d L esser yellowlegs are a beacon to the i de n tity of t hese bird s whi ch otherwise look a great deal l ike many other members of the san dp i p e r family. Leg co lor a lso is helpfu l in disting u ishi n g among the white egrets. These a 1 1 -white waders look simil ar a t a distance, and s i ze co mparisons m ay b e diffic ult to judge, but their fe et and heak co l o r s quickly gfve away t heir identities Great Egrets hav e ye llow beaks and b l a ck legs; Snowy Egrets, black beaks and legs with brig h t yellow feet; Cattle Egret s yellow beaks and legs; a n d white-phase Reddish Egrets, pi n k beaks with a black tip a n d dark blue legs. In man y heron s a nd egrets, leg c olors become especially brig h t Handbook of Bird BioloBLf 3 Figure 3 -36. Begging Bl ack-andw hile Warbl e r Nestlin gs: At the s ligiJtest /rmt that a parent may have returned with food, hungry young open w ide tu// y displa yi n g the hold o ral fla nges tsee also Fig .J-J 7). rhcse temporar y s\Ve/1-lngs Jl ril e side ofth e mouth dCl tlS wrgets for ildul t s feeding young. Photo courresv of l.
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3-44 Figure 3-38. H ee / Pad of Nestling Tou can; {vl1111y nestling cavity nesters,, such as woodpeckers anclwucans, have an e nlargemenl at the upper end of the rarsus terrnecl lhe heel pad II is thought 10 rPducethe.Jbrasion ofthewrws fmm the cau,gh linins of the nest c,wity. Geor9e A Clark Jr. for the breed i ngseaspn. The bright ora n ge feet of a breeding Green Heron are unmist akab l easltwalks in mudoralongdark logs like the bill, legs change color throug h the s l oughing off of dead outer sk i n l ayers to expose the rep l acement l ayer produced underneath. I n ce rtain cavityne sting birds such as woodpeckers, nest l ings have a special en l argement of the u pper end of the tarsus, the h ee l pad ( Fi g. 3-38). Heel pads probably reduce abrasion of the tarsus ca u sed by the rough lini ng of the nest, in the way that elbow pads protect a hocke y p l ayer. H ee l pads are shed at about the lime th e young leave the nest. A few k i nds of birds, such as ptarmigans and most owls, have feathers covering the legs and feet (Fig. 3-39a) Ptarmigans have extra feathers o n their feet during winter. These p r ovide in s ulation and offer a large r surface for support on snow, like a s nowshoe. Owls apparently have feathered feetto help suppress flight sounds that might alert prey Unlike the s i l e ntly flying noct urn a l owls, dayt i me fishing owl s lack feathered feet a n d their flight i s r e latively noisy. I n most birds the outer end of the l eg has some type of skin cov er i ng that resists abrasion and depending on the type oi bird, may Include scales, papillae, or l eathery skin. Patterns of papil l ae and folds on th e undersides of the toes ofte n reflect the functions the feet must perform.l11e feet of Osprey, for example have spiny-tippe:d papillae on the underside to fi rm ly gri p s l ippery fish ( F i g. 3-39b). I n Ruffed Grouse, an enlargement of scales along t h e sides of the toes creates sup porting winter "s nowshoes ( F ig. 3-39c). I n many birds, papillae patterns on the fee t var y considerably and ca n be used to identify spec i fic i ndividuals (C l a rk 1972; Smith et a l. 1993), much as huma n f i ngerprints are used to id entify individual people. I n the case of rare birds worth tens of thousands of dollars, such as certain falcons and parrots, knowledge of papillae patterns cou l d help identify indi v i duals stolen or i ll egally taken from the wild. The claws at the ends of toes often reflect a bi r d's habits. Species that climb tree trunks s u ch as nuthatches, Brown Creepe rs, and Bla ck and-White Warblers, have claws more curve d than those of nonclimb i n g species (fig. 3-39d). T hese claws he l p them grasp irregularities on bark without noticeably impa i r in g their abi lity to per ch lt is remarkable how well nuthatches ca n climb o n vertical trunks w i thout slipping or fa IIi n g o ff. Th e curved claws of Archaeopteryx are amo n g the c h a r acter istics indicating that it was arboreal in its habits (Feduccia 1 993). Ground-dwelling songbi rd s s u ch as l arks and pipits are not ed for their long hind claws. These conceivab l y cou l d h e l p them to avoid sink ing into mud or oth er soft surfaces, a l t h o u gh this idea remains ---Cornell

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Chapter 3F orm a11d Fwrd i o n : Tire Externa l Bird 3 4 5 a Papillae Ruffed Grous e S u m mer Win tor Nurthern Flicker Swainron's Thrush Purple Gallinule t=igure 3-39. Adaptations of Bird Feet: a : 111e feet a n d legs oi l"'if/J feat/>ers, which apparent l y S
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3 Pec tin.,te C l aw Figure 3-40. Pectinate Claw uf He r un : The mirlrlle rlaw In >om e birrls , scrrMed edg<' a; a preening tool The slwcture Is termeristles. Thi s is reasonable be c ause face a n d h ead feathers-i f t hey h ad t hem-woul d beco m e bad l y soiled when t h e b ird reac hed i nside messy <..arcasses to feed A m ong birds that feed regurg i tated, part l } l digested flsh t o thef r nestlings suc h as pelicans, the youn g ten d to have few or n o feathers o n their faces. Som e vu l tures a l so use their u n feathere d h ighl y vasc u l ar i zed head a nd neck to help reg ul<1te b ody temperature(Arad, M i dtgMd and B ernstei n 1989 ) ( Fig. 3-42). For example, when a T u rkey V ulture i s too hot, it s tr etches out ils n eck a n d in creases t h e f low o f blood thro u g h t hat regio n Excess body heal ca rr ied by t h e b lood is t h en give n off t h roug h the skin, from blood vessels near the skln's surface. W h e n col d, the bird r e tr acts its h ead and red u ces blood flow thro u g h the s uperfi c i al b l ood vessels th u s conse rving body heat. Th e u nfeather ed areas of m os l birds are o n the h ead and neck. Some of t hese areas a r e normally inconspic u ous, but become ve r y pro m i n e n t durin g dis pl ays Certa in North Ame r ican grouse h ave Com ell Lllbomtott t of Ornitholo[J'I

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Chapter 3-F orm and Function: The External Bird Figure 3 -41. HuatzinAdolt s and Young: a: The bizarre, pheasant-sized Hoatzins oiAmazonian South America build their nest in/ow branches overha n ging quiet wate1. b: HoM tins bear claws on thf! leading edges nf their small wings. When disturbed, they leap from t h e nest into nearby or wate1; then use the claws of all tour appendages to climb back up. Handbook o f Bird BtolotJtf 3

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3-48 Figure Turkey V ultur e: Turkey Vu/ turts and many other bare-headed birds can eliminate excess heat b)' stretching ott I their necks to expand tl1earea o(bare s kin and increasing blood llow through the skin of that r egio n Photo courtes)' ol Ray /Vfartorelli!CLO F i gure 3-43. B e arded Bel/bird: n1e Bearded Bel/bird, a jay-sized cotinga of northern South Amerfc.1, featttres a of slender, fleshy waNies, bla ck in color. which suggests ,1 beard Photo by C H. Greenewa/WIREO. GeorseA. Clark, Jr highly co l ored booming s ac s on the sides of t h eir neck (see Fig. 4-97). In Sage Grouse, the sacs lle on the breast and are i nflated by the expansion of the walls of the esophag us. The bare throats of male frigatebirds inflate like huge red bal l oons du r ing courtship d i splays (see Fig 6-44b). Other bare areas change seasonal l y: the enormous orange knob at the base of the bill of the male King E i der shrinks after the breeding season, as do t h e frontal shie l ds of some coots and other members of the rail fam i ly. Bare or sparsely feathered areas of the head often have pec u liar ou t growths of the skin suc h as the comb and throat wattles of the Domesti c Fowl the warty bumps on the face of the Muscovy Duck, or the s n ood of the W i ldTurkey-a limp, red f i nger I i ke p r ojection from the forehead. Pen dulous wattles also han g from the heads of New Zealand watt l ebi rds (see Figs. 1-92 and 9-28) and the spectacula r Neotropical be ll bir ds ( Fig. 3-43). A n u mber of species have feather-free ca s que s on top of the head, includin g t h e cassowaries of Australia and New Guinea ( Fig. 3-44) a n d the Mal eo, a brush turke y ( megapode ) native to the I ndonesian i s l a n d of Sulawesi Brilliantly colored eyelids occu r in birds of many families, including p l overs, pigeons, cuckoos, trogo ns, thrushes and Old Worl d flycat c h ers. I n some, such as the Wattled Broadbill and the Yellow-watt l ed Bulbu l -both of the Philippine I s la nds-the br i ghtly co l ored eyelid is also enlarged and flesh y In some b irds, such as to u cans and some parrots and honeyeat ers, an area a round t h e eye is bare and brightly colored. I n many h e r ons the bare area is between the eye and t h e base of the bi II, and the co lor varies with season Color s The t r emendous r a n ge of bird co l o rs, on both feathered and unfeat h ered parts, suggests immediately that birds have welldeve l oped color v i sion. I ndeed exper i me nts have verifi ed that many birds do see col ors, and the structu r e of their eyes indicates that they may be able to dis c rimi n ate a greater variety of colors t h a n can huma ns. I n addition, many birds can see ce r tain types of ultr avio let (UV) I i ght, which is invis ible to t h e u n aided h u man eye (Fig. 3-45) ( Bennett et al. 1 994). What advantages might t h is give them ?The answer remains a mystery, but ior a discus sion of this topic, see S i debar 1: The Amazing World of Avian ESP, i n C h apte r4. A l together the b i rd-human differen ces in visua l perception are so great that it is har d for us to u n derstand exact l y how birds see the world ( Bennet! et al. 1994). Cornell LaboratonJ

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Ci10{'ter 3-Fonn and Funetirm; The E.1temal B;rJ To get a sense of the full pal eue oi col ors array of pauerns round in th e more than you n eed only skim through a work such as Rirds of the World, by JJmes F. Clements. Strikingly namE>d birds appear o n eve r y page and the names profusion oi col ors: C l aret-breasted FruitDow, Silvery-throated Spine tail R edstart, Purple-bearded Bee-eater, Scarl etho odNI BJrbet, Fire-mned BowPrhird Pink throated Bril Ruhv-topaz Humming bird, Vlo l e r-neckec.J lorv, Opal crow ned Manakin, Cohalt-winged Pearl y-breaS1ed Cuckoo f}uff-throated Purpletuft, LiiJc-tafled Parrotlet, Sapphi r e-rumped Parrotll:'t, Mcllilchi t e Sunhird Gilt-edged Tanager, Glistening-green T,lnager, Citron-he,1ded Yellow-Finch. As these name s imp I )', the assortl'rism Figure 3-44. FeatherlessAdommenlsof tile Southern Cassowar) : Thisfltmm/lan l11rrl display< a l ltt{le IJony llelme/ -f)C)5-"II/y ()mtef rion ,JgaiMtthmn\ /,1/Ion a11d vine:. in the lnrrf s rJin forest hJIJi/,11; groreS!'JiiC', I lopp_\' w,lll/e lipped hrip./11 pmk.i taw .wd nl'c k. lhese lealUres, wmbtnt'l'l with tlw bird:, t:OJIll glossv hlaOmt .JSfNU. Phuttl V)' C. lt.>lpc NIRtO. Figure 3-45. Human Vrsus Avi.1n Visual Spec trum: When white light strikes tl prism lht uilltf('tll Wuelength; 11 wnt,tms are t'Jth hem to J c/1/lerenr il L<>nJler .vavelenslh;; as rerl re IJe ntle..o;s shr)l/et 1\,ll e ii"IIJ(Ih' 'uc/1 .J< vinii-'L /nth<> ,,/mosphere, <111 111 1 ,,s to produce il rainl1011. a: The portion of the stm > 5pec 1111111 1 /o humans. Th1s ts normall y termed ''vlsibhliJ.:hL" b: 1he port10n uf I he speer rum visillldo birds lh,lf can see m .1ddiriun tu '11'1sible light. Handbook of' Bird Biolotl'l

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3 50 ment of patterns is just as spectacu lar: birds are frec kl ed chev r oned, naped, co ll ared, cap p ed, crowned, hooded s hou l dered, browed spectacled, mustached, neck l aced spe c kled str ip ed, blotched, bor dered, banded, vented, chinned backed, cheeked, and crested with this amazing array of co l ors How are all these beautiful co l ors produced ?To understand t his, you first need to realize that sunlight i s a mixture of many different wavelengths of li g ht. Seen all together they look white, but when .a prism or water droplet in the air bends each wavelength to a different degree, the wavelengths separate, and we see each as a different color, as in a rainbow (see Fig. 3-45). When whi te light strikes an object, some wavelengths are absorbed by the object while other s are ref l ected back to our eyes Th e reflected wavelengths are what we see as the object's color. A red ball, a card i nal, or red paint appears red to us because it reflects only red light; the othe r colors are absorbed and never get to our eyes. Birds employ two different systems to break light apart into its component wave l engt hs-pigments and t h e microscopic structure of feathers. Pig m e nts are colored substances that c an i n principle, be extracted from feathers or other parts of the skin. ( In practice their act ual extraction may be very difficult. ) Th e color of pigments can be seen even after the physical structure of the material in which they are embodied-a green leaf a red bowl, or a brown feather-has been destroyed. In contrast, s tru c tur a l c ol o r s depend on the a c tua I physica I st ru cture of the feather to reflect certain wavelengt h s of light. Destroy that structure and you lose the co lor, just as you l ose the rainbow i( you destroy t he prism. Piaments T hree main types of pigments are found in birds; melanins, ca rotenoids and porphyrins Melanins whi ch usually occur as tiny g r an ules in the skin and feathers are the most common. Depending on their c oncentration and distribution, melanins can produce any shade from the darkest b l acks through browns, red-browns yellow-browns, and pale yellows Mel anin color s the all-black Common Raven and American Crow, the reddish phase of the Eastern S c reech-Owl, and the yellowish down of a young chicken. Birds synthes i ze thei r own melanins from amino acids, which they obtain from the proteins in their diet. Melanin provides more than color for feathers th ough. Feathers contain ing melanin are stronge r and more resistant to wear than feath ers with other pigments Some r esearc h ers suggest that the melanin gra nules themselves provide the added stren g th, but others attrib ut e Tt to the higher leve l s of keratin found in fec:tthers with me l an in ; indeed both facto r s may be involved. White feathers, which lack any type of pigment are the flimsiest tt is no s urp r ise, then that most birds espe cially white or lightly colored ones, have dark wings o r wing tips-ex tra protection for the feathers m ostvu l nerabletoabrasion during flight ( Burtt 1986 ) Dark win g tips are especially common in bird s that f l y at Cornell Laboraton1 of Ornitholo&li

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d1apter 3-For m and Function: The External Bird hTgh speeds or spend a l ot of t ime flying, s u ch as gannets, terns, a nd gulls, i ncluding Common andArcti cternsa nd Ringbilled and H err ing gu ll s (Fig. 3-46). Carote noid s produce reels as i n Northern Cardi nals, oranges as in male Blackburn ian Warb lers, and many ye l l ows, especially the bright yellows of blr d s such as Yellow Warblers, go ldfin c hes, and canaries U n l i ke m elan ins, carotenoids are synthesized onl y by plants. Blrds must therefore acqui r e them preformed i n their diet either by eating plants or by eati n g somethi n g that has eaten plants (B r u s h 1 990; Hudon 1991). In some bird species. differences in the specific types o f caro tenoids i n the diets of i ndividuals Inhabit in g different locations prod u ce r egiona l co l or var iat ions. This occurs in the European G reat nt, whose young nre more ye llow underneat h when fed on caterpil lars from dedduous r at h e r than co n iferous wood lands ( Siagsvold a nd Lifje l d 1 98 5). Som e colors, such as the olive-g reen of t h e female Searl et Tanager, result from the Interaction of both melanins and caroteno i d s in the same feathers. The third g r oup of plgments, porph y rins, produce reds, browns t greens, or pi nks in a number of d i ffe r ent avia n orde r s They interact with mel anins to produce the browns of many owls, and area l so found i n pigeons a nd gallin aceous birds. tn eggsh ells, the y may appear pink o r red, or they may be masked by me l anins. Porphyrins are most strik ing, however, in the b r illiant reds and g reens of the turacos a family of 3-51 Figure 3-46. Light Bird s with 0,1rk Wing Tips: Many whit e or /ig/1/-co/ored birds that spend a lot of lime llying have ctark wing lips c:olored with the pigmellf melm1in. Feathers with much melanin are stronger and more resistanr to wear than feathers with no ptgme11ts, or other types of pigments. Species from left to right; Northern Canner Common Tern, /-!erring Cull Americ.:Jn White Pelican Lays an AIIJa(toss Handbook of Bird Bioi oM

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co lorful African b irds related to New World cuckoos The porphyrin pigment turacoverdin, whi ch produces the gree n body plumage of many turacos i s one of the few gree n pigments known from birds. Mosl greens on birds as in the parrots a reproduced as str u ctural col ors that are modified by overlying carotenoid pigments. Porphyrins are complex nitrogen-containing molecules rel ated to hemog l obin, which birds (and oth er living things ) make by modi fying amino acids Althoug h the exact chemical struct ur e varies from pigment to pigment, all porphyrins share one significant feature: they fluoresce bright red under ultraviolet light I f you have eve r seen an exhibit' of minera l s at a natural history museum you may r ecall the da.zz l i ng colors of the fluoresce nt r ocks displayed under u ltrav iolet (or 11black ) light. Feathers with porphyrins glow in the same manner. Abnormalities and Vari atio n s i n Pig m e nt C olor s If you take a ca r eful look at the birds coming to your feede r you will see that not all individuals of t h e same species look a l ike. For ex amp l e House Finches vMy in the a m ou n t of str eaking on their breasts a nd in the extent of the red areas, as wel l as in the exact shade of red. Color variations like these are cotnmon and normal. But sometimes a truly unusual individual shows up: perhaps a House Finch with a w hite h ead, or an American Crow w ith white patches under its wings. These types of co lor abnorma l ities are discussed here. Some odd colo r ations are caused by abnormalities in a bird's pigmentation. The most common cond iti ons involve the reductio n or absence of melanin. Bir
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Chapter 3-Form and F unctiow The Btrd Baltimore Oriole Plumage colors may be altered by a l l sorts of e n viro n mental fac tors. Exposure to sunl i ght, for e)(ample, may lig hten feather colors. Birds in ope n areas that: receive lots of d i rect sunlight, such as deserts, are especiall y susceptible, Consi der American Kestrels, found in a wide rangeofhabi t Jts. B irds from Arizona deserts l ook very m uch like birds from M i chrgan whe n t h eirfeathers a r efresh in the fall. After a few months, however Arizona birds are so much paler t han Michigan birds thatthe two look like dlfferent species. Before such color changes were understood1 museum scientists sometimes classified the sun-bleac hed and unblea c hed specimens as separate races or species. In industrial areas, air pol l ution may affect feathers, givi n g b irds a coating of soot that may mask thelr true colors. When the use of soft coal as fuel was restricted in Pittsburgh. Pennsyl vania in 1'940, the nat ural h i story museum began getting tel ephone calls from bird watchers tryillg to identify "a han dsome little blrd fn chestnut gray, and white with a black bib." Many were disappo i nted to learn t hat the ''neW11 b ird WJS only the male House Sparrow without a coating of soot. Even in relat i vely clean areas, tree-climbing b irds such as woodpec kers and creepers may di rty their plumage by contad with ba rk, Col orful soil s and foods also may stain feat he rs. Birds that dust bathe in soils o( certain consistencies cannot always remove all t h e dust by shaking, a n d may thus acqui r e t h e general co lor of the soil. In southern Brazil for example, certai n Ho use Sparrows may acquire a pinkish tfnge from the reddish soil of the region-a bi t o( a cnange Handbook of Bird BioloB' I 3 Figure 3-47. D owny Woodpecker and Baltimor e Ori o le w i th N o Mela11in: When a genetic mut,1(ii'Jn prevents
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Georee A. Clark, Jr. Wavelength Wtwe len gth : .>E L l : AALl[ !\A& 0\:/Tv: v :vl\J: v Wave 1A Wi!v e /8 ; : : lmttal Wave : : (\/\ : 1\ (\ [ (\ l V]V!V \/\/\& . Wave2A Wave.:?B . . . Wave3A a F igure 3-48. Patt erns of I n t erfere nce f r o m Two Ligh t W aves: a and b = initial wave heights which ma y be positive ( + ) or negati ve ( ): c =wave height resulting from interfereflce ( determines perceived brightness ) a: The combination (or ''in terferenceN) of two light waves ( 7 A and 2A ) in .Yhich crests and troughs line up perfectly results in a new wave (.3A) with twice as high. n1e wavelength which determines the color, remains the sume butt he color will appear twice as bright. b : Waves I 8 and 28 interfe r e resulting in l"'illle 3 B. In this case, however, the wave crests and troughs nearl y cance l each other out, producing very low waves, which will be seen as a dull, nearly black ve rsion of the original color. Again the actual color remains the same be c ause th e wave lengtl1 is unaltered. If wave crests and overlapped perfectly, the result would be a straight line viewed as black. Wavelength i ..; A::2/4 .---'=. ( wave J B ( a+ (b)=e) b from the House Sparrow s usual browns and grays. Some geese, ducks, swans, and cra nes that feed in water containing iron oxide (r ust ) turn r eddish as the iron precipitates out on their feathers; this can be espe cia lly noticeab l e on the heads of Snow Geese. Birds even acqu ire a few of t heir colors w h i l e eating. Berr ies may stain th e feathers around the faceand vent of berry-eating birds; pol len ma y discolor the faces o f birds probing flowers for nec t ar or insects ; and ha l f-digest ed shrimps may turn the pure white fronts of penguins a splotchy p i nk. Structural Colors Two kinds of s tructural col ors occur: iridescent and non irides cent. Both resul t from t h e microscopic structure of t h e feathers, whkh causes on l y certain wave l e n gths of l i g h t to be reflected. Irides cent. colors as on soap bubb les, the "eyes" of a Peacock's p l umes and the thr oats of ma n y hummingbirds, are very bright and change with the ansl e of v iew-so they appear to glisten and shimmer as the bird moves. Ir i des cence is produced w h en l i g h t waves ref l ected off certain str uctura l layers within (lattened barbules "interfere" w ith one a n othe r somewhat the way that wfdening circles from pebb les tossed into a pond interact when they contact each other. Depending on whether the contacts a r e wave crests or troughs, the r esu l t can be tal l er waves, s horter waves, or a complete can cellation of lhe waves ( Fig 3-48). The eye i nterprets these different wave heights as different brightnesses of color. Only Interference patterns can p r oduce the "super bright" colors seen on i ridescent parts of feathers. Cornell Lahoratortt ofOmitholofj'l

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3-Form. att d F rmdi o n ; The Extem a l Bird 3 Feather appei1rs blu e d u e t o sccll tering of blue light w-aves S mall air vacuoles that sca lier blue lit;ht Cells, termed "cloudy cells'' or "11/ue-produring cells, made oi keratin, w hich cont;,in the lightVJcuoles H o l d a Peacoc k feathe r a n d slowl y tum i t from side t o side, and you' ll see a series of glistening colors appear a n d d i sappear. T h is o cc urs beca use atdiffere ntan gles lig h t bou n ci n g off and go ing th r ough the compl ex laye r s in the ba r b u les I n terf e re wit h eac h ot he r i n diffe r e n t ways : at eac h angle some wavele n g ths are brig h ten e d and othe r s are can c e ll ed before t h ey reach your eye. At eac h position yo u see only t h e bri ght e n ed co l o r s ( S idebar 3: Iridesce n ce) I ridescent colors rar e l y occur ol') a bird' s flight feathers probably beca use t h e flattene d barbules r equire d to r eflect I i g h t would not be s turdy enough for fli g h t and because a n y wea r woul d c h ange the feather s truc ture, destroying its co lor (Gree n ewah et al. 1 960). Fur. thermore flash i n g i ridescent colors o n mov i n g wings m ight h inder a bird's abilit y to h i de f r om predato r s Nonir idescent st ructural colors ar i s e w h e n t in y vac u oles ( pockr ets) of air w i thin ce l l s i n the bar bs s c a tt er i ncomin g light (Fig. 3-49 ). According t o the l aws of p hysics. when ever pMicles s m aller a part i cu lar wavelength of li ght are sep a r ated by dista nces g r eater than thatwave len .gth a ll incoming wave l engt h s of roug hl y t h a tsTzeor l arger will be scatt e r ed: absorbed by t h e par t i cles an d re-erni t ted in a n ew !C ontinued on p. 1) H a n dboo k of B i r d Biolo811 Bro1vn Feat/> er nppears brown due to light passing throu g h the brown pigment m elnnin keratin Sheath Melamn Granules F i gur e 3-49. Cross S ec t ion throu11h a Blu e ja y F eathe r Barb: When light is scattered b y air vacuoles in the blueproducinfl ells. the ie,uh er appenr s blue. When light is the feather; the feather ilflpears brown. I n some birds th e keratin layercomainsp i g ment. For m.1ny green b itds, s uch .1s parrots, IMV<' a ye llow pigment here that adds to rheKJtrered blue light t o produce green. Adapted frr>r!l Welty .Jnd B ,wtisM /1988, p 49 Fig. 1-t 9t\J.

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3 Georee A. Clark, Jr Sid e b a r 3: IT\IDESCENCE S a n dij and B ill Podulka Light Source Eyeo( Observt>r 1, To understand the details of how feather structu r e ca n produce iri descent col ors you must first un derslond the physics of how a thin f ilm affects light. For this discuss i on, please refer to Fig. A. When a beam of light ( l l hits a thin, translucent film, suc h as a coat i ng of o i l on water, or the membrane around a soap bubl?le, som e of it is reflected (2) and some enters the film (3). Whenever light moves between media with d i fferent densities, it is bent (ref racted )-as occursatpointA-and the degree of refraction depends on the difference between the two densit ies. Some of the refra c t e d llght 11Yi1Y' lravel on a n d exit the film (4), but some is reflected off the bottom surface (5). Si11ce the eye of any observer is much larger than t h e dista11ce between the paths of light waves 2 and 6, they wil l both be seen atthe same time When these two light waves meet inside th e eye, the com brnat i on produces inter ference and the typ e of interference depends on whether wave crests or troughs arrive at the eye at the same time !see Fig. Whether crests or troughs arrive together depends on the extra distance in the film (A to B tu CJ that light l eaving in beam 6 has lraveled, compared l o l ighlleaving in beam 2. Tha t ex tra distance in turn dl:lpend s on three things: the a ngle at which the incoming light strikes the film, the degree of refract i on, and the thitkness of th e f ilm. In the simplest case, in which light of only one color, such as green, rs involved, the result seen by the observer ( light waves 2+6) w i ll be e i ther bright green (when wave crests meet ), dull green !whe n partial crests and/or troughs meet), or b l ack twhen w<1ve crests ilnd troughs meet and cancel each other out). For a sta tionary observer watching a movi ng fi l m (suc h ils a drlftlng soap bubble), under g r een light the color will ap pear to cha nge f rom brig h t green to dlJI I green to black, as the f ilm moves changing the a ngle at whic h the inco m ing lig h t hits t h e fil n1. When sunlight, a mix of a l l colors, s t rikes a fi l m, at each ang l e be tween the observer and the film just one color will be brightened the o n e fo r which wave crests meet-and n will Air 1\ir be seen to the exclusion of the othe rs. Thi s is why you see a series of colors -as you turn a peacock feather in your hand, c h anging the a ngle betwee n your eye and the feather. The iridescent colors of feathers, like those of a soap b ubble, result from l fght i n terference cre
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Chapter 3-Form and Functi on : Th e & t e m a l Bird Ruby-throa t e d H u mm ing bird 7!::0 I \\ Observer S e e s B r i g ht Red Observer S ees Obserwr Dull Red Figure C. Angles I nterference, and Iridescence: Schematic representation of how different arygles betwe e n the sun Ruby -throated riummingbird t/lfoat and obs erver produce differ e nt interfe r ence patterns anrlthus different brightnes ses of red. Angles and r e sulling imerference palterns Me not nec essaril )' accvrate. l i ght reflecting off the top surfa c e of the v;t cuoles i n I'OU s e e ts the sum of all these layers acting together and the more l ayers involved the b ri ghter the c olor. I f you hav e ever watched a m ale Ruby throated Hummingb i rd p ro b in g a flower, y ou may remembe r h is flashing c h anging c olors, his throat varying f rom brilliant red t o near b l ack. As h e moved he a l t e red the angle formed by your eye, the re flecting surface, a n d the l ight sourc e. H is throat barbules are stru c tured so that interfer e nce pattern s can o nl y brlghte r l the red wav e lengt h s a n d the bri g htness d epends o n the a ngle of view. At some ang les all wave lengt h s cancel each other out, a n d you see t h e thr oat as ( fi g. C) Variations on this struct u ral theme a r e as endless as the array of i rides cent col ors they produce, The mel a nin ma y be sol i d o r air-iilled and may be i n n at dis ks, o r in rounded, h exagonal or flattened rods. Some t i mes the m ela n in gra nu les a r e t igh t l y packed, a t othe r times they h ave sp9ces betwee n t h em, roug hl y forming a g rid The col ors p rodu ced may be as pure and brill iant as the red throat of a Ruby-throated Hum mingbirdormaycont a in a duller mix of wavele n gths--as i n the g r ee n s of som e trogons Some col ors resu l t from a combinat i o n of irid e scent colors--as in the copper ( a mix of red a n d yellow-green iridescence) on som e Afri can sunbi rds. The precise arrangement of the layer s o f melan i n gra n u les r est ri cts Handbo ok of Bird Bio lo&IJ 3 the range o( colors produced Hummingbirds (as mentioned above ) are notorious for their quickly disap pear i n g colors-chan g in g from g lit tering brillia n ce to black w i t h just a s l ight change i n angle. So m e, such a s the R u b y-throat ed Hummi ngbird can o nl y produ ce r ed or b l ack on th e throat feathers but others m ay d isplay severa l c o lors in ad diti on to b l ackness. The col o r s of a p eacock rea the r a r e numerous--ranging from bronze thro u g h blue-green, but they never complete l y disappear to form black. O n e oi the most b eaut i ful birds 1n the world, t h e Resplendent Quetz a l of Ce ntral Amer i can cloud forests varies between gol d-green and b l ue-gree n with a tou c h of violet at times The inte n sity and b eaut y of its 'olors has placed it as the national symbol of Guate m ala; in t he past was worshiped by t h e Mayans a nd Aztecs. A l thoug h some of the most spe c tacular irides cent c o l ors occu r on tropical species man y North Ameri c an birds a lso display iridescence-and some of these can be seen at your feeder. E u ropean Star l i ngs, many grack les an d cowbirds, Wild Turkeys, Ring-necked Pheas ants, and Wood Ducks a l l glitter w i th irid e s ce nt hues. But irid escence is not limi ted to birds Some s nakes (such as b oas), lizards f ish ( rainbow t rout a nd many popular a qu a rium spec les such as n eon tetras ) a n d in sects (especial l y butterflies, moths, a n d beet les) produce iridescence. A l t hough t h e y use d1fferent sub stances and str uctures to form the col ors, t h ey still use the p rinciple of interferen c e from t hin films Perhaps the mostawe-inspir in gas pect ofl ridescence-even beyond the b eauty of the colors themselves-is tharthepurity, r ange, a nd brillian ce of t h e col ors p r oduced by each spec ies aretig htl ycontrolled b y minute stru c tures w hose size density a n d shap e must be highly ac c urate-som etimes t o within 4 ten-millionths of a n i n ch ( 0.0000 1 rnm),

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3 58 Blue a Bmwn b Fig u re J-511. Blue }.1y Feathe r Under Diffe r ent Ligltt Co nditions: a: W/Jm tight refleus off the top surfac:e ot a Blue fay feather, the ieather ,1ppe,1rs bright blue due t o the det.1ilcd struc ture of the fe,11her. b: When light is transmi t ted through a Blue laytemher, the appeal'$ brown due !C> the pigmenf mel text for htrtlrer explanatio11.! Photnscollrte syot Carrol l GeoreeA. Clari<,Jr, d i rec ti o n Th e shorte r the wavelengt h the more s tron g l y it is scat t ere d. In a feather, the
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Chapter 3F o r m and Function: The External Bird 3 -59 a b Figure 3 51. Thrushes U nder Different Lighting Conditions: Black-and white photographs ol Old World thrushes. a : Birds il lu min ated by lig ht conditi o n s visible to hum ans. b: Birds illu min ated only by ultraviolet lig ht (wavelengths 320 to 400 nm). Note that b does not show the birds as they would appear to a bird whose vision is sensitive to both visible and ultraviolet light but does s how the additional ultraviolet plumag e features that mi ght be visible to a bird but not to a human. The way these plumages might actually appear to a bird th a t sees in both the visible a nd ultraviolet r,1nges is p r obably somewhere in between the images s h own in a ,md b Species from top t o bottom are : mal e Eurasian Blackbird Song Thwsh, Taiwan Whistling Thrush, and male Blue Whistling-Thrush. Photos co urtesy of S t aff an And e rsson. Handbook of Bird

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3-60 Geor9eA. Clark, Jr. For in -dept h ell:planat i o n s a n d clear illustrations of how st ruc tura l c olors are produced in birds see Simon ( 1971 ) and Gree n ewal l (1960) Functions o f Color and Color Patterns Feather structure and pigments combi n e t o make birds amo n g the mos t colorful animals on eart h. Th eir bright colors and s tri king pat terns a r e rivaled onl y by thos e of coral reef fishes an d butterflies. For all an imal s includingbirds, color a tion is an evol ution ary co mpromis e between hiding from predators and being con sp i c uous for socia l in teradions such as terr itorial defense courtship, and m ate choice. For most a nim als h oweve r conceal ment i s the more c riti ca l need. just as the du ll cryptic c olors of m os t m ammals, r ept iles, amphibi a ns, a nd fish help them to r emain inconspicuous so, to o do most bird s sport earth tones that r ender them hard t o see. Nevertheless, a l arge numbe r are brightly coloredperhaps because fli g ht a ll ows them to escape most predators, perhaps because bright colors are conceal ing in some habitats ( sunlit, fruih) n d-flower"laden fo r est canopies, for instance ), or perhaps because colors a r e so crucial for b i rds socia l i nteract i ons We probably will never know exac tl y w h y each bird l ooks the w a y it does but we do know that color and pattern, like mos t oth er attributes, resu l t from generations of natural selection. Indi vidua l s whose colors best m eet their needs r a i se m ore young and pass to those offspring their favorable colors and patterns Over time, th i s hand of evoluti on" continues to fine-tune eac h bird's appea r ance. T hus when we. view a bird, we must r e m ember that it i s not a finished product, but one under con ti nu ous cons tru ction Some p atterns remain a m ys tery to u s Why, for e x amp le, is th e Bobolink light above an d dark below, not the reverse, like most birds? With ca r eful observat i o n and interpretation h owever ; we oft en can deduce which selective forces produced the colors and patte rn s we see in b ird s today. Thr oug hou t the fo llowing discussion of bird colors and their iunc tions1 keep in mind that most observat i o n s a n d experiments with birds have assumed that thei r co l o r v i s i o n as well as that of their predators, is simi l ar to ours. Onl y i n the ear l y 1 970s did researchers begin to r e alize that birds see some types of UV light, and that some birds m ay be ab l e to discriminate a greate r number of col ors than we do. Our understanding has thu s been hampered by o ur own perception o f the colors a r o und us. As we strugg l e to g r asp the way the world really look s to birds and their p r edators some of our l ong-held beliefs about the roles of colors and patterns o n birds may be challenge d Coloration and Patterns Predation is the chief caus e of death in m any birds esp ec iall y smaller ones. Avoiding predation therefore ap p ears lobe the main reason that so m any birds h ave evolved cryptic markings Not on l y Com ell Laboraton1 of Omrtholo8'1

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Chapter 3For111 and Function: The Erternal Bird is co ncey its lemm in g prey if it blends into the w h i t e a r c ti c la n ciscape. The o nl y d a t a t o sup p ort thi s idea, h oweve r come from e x pe r iments on cap tiv e B l ackh eaded Culls. which became muc h less effect iv e at capt urin g fish in a tank from the air w h e n the under s ides of th eir o rdin ar il y while wings were d yed bl ack (Go t m ark 1987 ) Differ e nt predators h owever, h ave diffe r e nt v i s u a l capabilities so we mu st n o t assumet h a t all preyappear asco nspi c uous o r as crypt i c to predators as they do to us. For inst a n ce, mos t mammali a n prPd ators s u c h dS c Jts an d raccoons, as well as n oct urn a l av i a n predators s u c h as owls, ap p on tilt! har,k ot illl llmenul/1 Wuodwc:k rende1 1r virruol/y itJVi>i/)/e .1gains1 the leaf litter oft/1 e floor Photo '-'OUI'" It'S\' ot'}ohn Trott/CLO.

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3 62 a c Figure 3-53. Cryptic Coloration of the W illow Pt.1rmigan: a: In win fer, t h e plumage of males and females disappears againsl t h e s n ow-covered tundra. P IJOI O by Dan S tosit s/C LO. b: In spring and fall, J5 the m,Jie molts his pclf c hy l>rown-and-1.vhit e plumage matches 1he pa1chy snow cond ilions of 1he lundra Photo b y johm1y johnson/Bruce Col e man Ltd. c: In s ummer, the female's mottled brown feathers make her nearl y impossible ro see as s h e incubates l1et clutch. Photo cour(f!S)' o(A/ Corneii/CLO, Georae A Clark, Jr "stay put i n it. The p a le Pip i ng Plov e r for example spe nd s mu c h tim e on white sand y b eaches, w h e r e it is diffi cult for eve n the most persistent b ird watcher t o s pot. Many bird spec ies with precocial yo ung-th ose, s u ch as du ck lings that hat c h with feathers r eady to l eave the n est a nd for age with thei r pa r ents-ar e m os t c ryptically colored in the p e riod b efore they can f ly. Then, their best d efense against predator s is t o b e "in visib l e." Y o un g t e rns and skimmer s o n b eac hes, for instance bl e nd so well into thei r background of sand and g r ave l thatthey a r e in dan ger of peopl e stepping on th e m Birds that we t h ink of as ga udy in pic tures or capt ivity may actually blend into thei r n a tural surround ings. A v i sitor to th e tropics m ay spe nd a long time staring at a hu ge s qu aw k1ng tree b e f o r e finally glimps ing o n e of the many l a r ge, b ri ght g r ee n pa r rots within. Even birds as bri ll i a ntl y colored as K ee l -bi ll edTo ucans and Paradise Tanage r s virtually disappear agai nst the sun dapp l ed tr opica l can opy overhead. Di s ruptive Coloration In a dditi on to resembling th e i r g r o unds, so m e b i rd s hav e dis ruptive c olora tion. Like the "ca mouflage of military gear, disruptive plumage has patches, streaks, or other bold patt erns of color that b r eak up the shap e of the b1rd, catching the eye and dis tra cti n g the obse r ver f rom r ecog n izing t h e whol e bi r d aso n e form. F o r exa mple, the two bold, bl ack n eck bands of the K ill d ee r com bined with its brown back mak e i t v irtu a ll y i mpossib l e to distinguis h aga in s t a pebbly fi eld o r b eac h (Fig. 3-54). S imila rly, the dark or light eye lines found i n so m a n y birds a r e thought to h e lp disguise the oth e rwise con spi c u ous eye. Disruptiv e col orat i on has the ad ded advantage of providing camouflage on a var iety of ba ckg rounds. Downy you n g sho r e bird s in the a rctic tundra hav e varie gated p lumages that breakup theiroutlineso muc h that predators (and hum a ns, as well) hav e trouble seein g them i n a ran ge of dif feren t vege t ation types (see Fig. 8-125). Com elL laboratont of Ornitholoe'l

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Chapter3-Form and Fu11ction: The Extemal Bird Counter s hading Many bi rds are h ard to see because t hey a t e darker o n top than below, a pattern know n as countershading Eastern King birds, Northern Mockingbirds m ost gulls, and many of the small er p l overs, sand pipers, and songb.irds are familiar examples (Fig. 3-55). With t h e darker back l it b y the bright sun overhead and t h e lighter underparts i n the s h a d e of the bird's own body, the bird appear s as nearly o n e colo r and unti l i t moves, p r edato r s have difficulty seein g it as a three-dimensior'lal object. In add iti o n w h ite underparts may reflect the co l or of the ground, producing even more effective camouflage. Countershadi n g i s best developed in o p en co untry birds that are vuln erable to distan t predators hunting by s i g h t It also is common in b irds that spend much time on the water, s u c h as l oo ns, grebes, ducks auks, a n d many pelagic birds. Behaviors that Aid Concealment Bird s may i ncrease the benefits of cryp t ic p lumage w ith certain behaviors. S i mply holding s till i s one good way to avoid attracting predato rs. By f r eezing into immob ility and flattenin gagainstthebeach, young terns and gul l s e liminate t h eir shadows and look j ust like bumps on t h e sand. The n octurna l potoos, odd Neot r op lca l r elat ives of nighthawks, also compleme n t t h eir mottled brown-and-gray plumage with behavio r They spend mosl of the day justs itt ing, ofte n perched o n the stu b of a dead tree limb with neck stretched up and l a rge eyes closed 3 Figure 3-54 Disruptive Coloration I in Killdeer: Note how the black neck bands of the adult and rwo c hicks break up each bird's outline, making it hard to distinguish against the bus)!, pebbly background Photo courtesy of M,1ry M. Tremalne/CLO. Figure 3-55 Countershading i n BlackTur nstones: The shadow cast on the light-colored underparts of a st,mding Black Turnstone helps to offset the contrast between the dark upper and lightlowerportions makfngth e bird appear !'IMler Q88insc tht? IJackwound, and more d;((ic uh to see. This effect would not work if the birt;l were li ght above dark below, as demonstmted by the upside down which is much easier to spot in its dark, rocky habitat. This pattern of dark above and light below is knnwn as countershading. and is found in many species of birds. of Bird BioloBI.f

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3 64 Figure3 56 B irdorS t iddTheCommon Pmoo o( Central and Sour/! America, a rel.ltive of North Am e rican nighthawks sponds mosr of ils day motionless, often pernfled at rile e nd of a snag. Photo bv / II. R emse nNIREO Geor9e A. Clark, Jr. looki ng for a l l theworl rl likean extension of the stub ( Fi g 3-5 6 ). Many owls, such as Long-eared Owls and screech-owls, adopt simi lar"stick postures."The f r eez i ng stra t egy a I so works for many p r edators, such as herons prospecting for fish or frogs along a shoreline. In some cases, h owever, movement enhances concealment. American B i tterns b l end the i r strea k ed pattern with reeds by standing with thei r bills poi nted skyward. If wind b l ows t h e reeds the bird, too, may sway slight l y f rom side to side (see Fig. 2 17 ) C onspicuo u s M arkines a nd P r e d ation Many cryptically co l ored birds have conspicuous mar kings that become obvious on l y when the b i rd flies off. Thewhiteoutertail feath ers of juncos meadowlarks and Hooded Warb l ers; the black-and white f light feathers of Wil l ets; the whlte "windows" in the primary wing feathers of nighthawks; t he bright orange-and-white rump patch of Killdeer; and the white rump of Northern F l ickers are examples (Fig 3-57). When such markings are suddenly revealed they may startle an approach i ng predator, lead i ng it to hesitate or to strike i n the wrong place and miss its target. Because many of these conspic u ous markings disappea r when the bird lands, suddenly hiding the bird's position, they also may confuse predators that had focused primari l y on the bold markings d u ring pu r suit. The evidence that this d eflective c olorat i o n serves an anti preda tor (unction is scant however. Birds somet i mes reveal these hidden markings even w i thout flight. A junco or Hooded Warbler hopping on the ground, for instance someti mes spreads and contracts its tail feathers s l ightly flashing its white markings p r ominently. The d i splay of hidden conspicuous marki ngs may actually fun c tion more i n social interactions between members ofthe same species than i n interac t ions between species, but mor e researc h i s needed to evaluate the various possibi I i ties. Prominent markings i n other anima ls, such as insects and f rogs, may warn predators that the individua l is distasteful. However, no ex ample of a consp icuous, distastefu l bird has yet been found. Moreover the few known poiso nous birds, such as certain membersofthegenus Pitohuifrom New Guinea, show noobvlouswarningcol orati on. T hese poisonous birds are reddish brown-no more strik ing in appearance than the non po i sono u s species of t h e same genus i n other parts of New Guinea. R e duct ion of Glare for F oraeine Birds forag i ng i n bright sunlight may expe r ience glare as l ig h t is reflected into t h eir eyes from lightcolored areas around the eyes !ores, and upper beak. The g l are may interfere with their vision, r e ducing the i r foraging effi ciency. Dark co l o r s nea r the eye may reduce s u ch glare, as in t h e face mask of the Common Yel l owthroat, the dark eye stripe of the Ceda r Waxwing, a n d the dark head and upper beak of many flycatchers, including the wood-pewees and pho e bes. Some Cornell L.aborator11 of0rnitholo8'1

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Chapter 3-Form and Function : Tlte &ternal Bird 3 Nonhem Flicker D ar k -eye d junco evidence for this hypothesis exists. When Burtt ( 1984 ) painted the normally dark upper beaks ofWillow F l ycatchers white, the birds foraged in the s had e more often than those Wit h the normal beak color. When the birds with whitened upp er beaks did forage in the sun, th ey had lower foraging success. In addition Burtt (1986) noted that species of North American wood warb l ers with dark upp er be a k s forage in sun l ig ht significantly more often than those with I i g h t upper beaks The Role of Color and P a tt ern in Social Behavior Birds, like humans, may use color and pattern to distingu ish amo n g species sexes, ages, o r individua ls. The m ore that resear c h ers stu dy co l oratio n h owever, the more they realize its importa n ce in male m a l e (or fe mal e-fe mal e) competition for m ates, and in mate choi ce. Many ways that coloratio n funct ions fn i nteraction s between individua l s are dis c ussed below. Handbook of Bird Bioloel! Figure 3-57 Deflective Co l oration in Bird s : Man y otherwise cryptically col ored birds have mnspicvous markings thilt become visible nnly when the bird flies or spreads I t s wings or tail S u ch markings termed d e flective coloration include the white outer tail feathers of Dark-eyed Jvncos, th e while rump of Northern Fli ckers, .1nd the black and white patches i n th e flight feathers o( Willets. Although resear che r s ha1e long assumed these mar kings evo l ved as antlpredatnr defenses-th e birds reveali n g them suddenly to startle or confuse approac/ J ing predators there is little evidence for this. A l ternatively, they may fu n d ion i n socia l i nt eraCtion be t ween conspecifics. O r ,lwings by Ch.ules L. Ripper.

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3 Species Reco gnition A bird must recognize other members of its species ( termed con specifics) to fi n d a mate. Matings between species (hybridizations) often are evol u tionary dead ends either because no young a r e pro duced or because the hybrid offspring do not survive or reproduce as well as offspring from two parents of the same species. Hybri dization sometimes occurs when conspec ific mates are hard to finq. For ex ample, hybr i ds between the Blue-winged Warb l er and Golde nwinged Warbler, known as Brewster's and Lawren ce's warb l ers are selected as mates primarily when pure blue-winged or golden-winged individuals are not available (Ficken and Ficken 1968) Hybrid pairing between a Blue Jay and a Flor i da Scrub-Jay occurred when the scrub-jay was the last female of its species remaining in the coasta l scrubs of north eastern Florida. Hybrids occur frequently in captivity, where the choice of po tential mates is limited. This is especially common amo n g ducks. For example t h e Wood Duck of North America and the Mandarin Duck of Asia do not hybridize in nature part l y because they never meet Th e y have hybr idized in captivity however, when their mate choices wer e r estricted. Because individua l s that mate with their own spec ies u s u a ll y p roduce more young this tendency is strongly favored by natural se l e c tion. As a r esul t birds have evolved many different me c hanisms to ens u re thattheymate with the correct species. Appearan ce, vocaliza tion s courtship displays (see Ch 6 Co1,1rtship Displays), anatomical and p h y s iological differences ( size sperm-egg incompatibility)1 and other behaviors probably a ll p l ay a role. A l though researchers have long assumed that col o r and pattern both fun c tion in species recognition devising expe r iments that clear l y dis t inguish their importance diffic ult. Therefore little supporting data ex ist forth is idea. Moreover, when obvious species-specific ma r k ings such as the red epaulettes of the male Red-wi n ged Blackbird, are exper i mentally c overed up, the sexes do continue to establis h pairs ( Searcy and Yasukawa 1983 ) i these experimen t ally altered males are recogn i zed as conspecifics by the o th er ma les. Interesting l y t h e al t e r ed males were less able to defe n d their territo r ies. Clearly, species recogn i t i on invo l ves a var iety of cues a c ti ng togethe r b e havior plays a key role and species specific color patterns also influence how consp ecifi c s treat one another. Age Recognition As discussed earlie r many different birds ( gulls Ame ri can Red starts, Red-winged Blackbirds, and others) have distinctive subadu l t p l umages before the y become sex u ally mature. We know that birds recognize age differences b ecause, given a c hoi c e they usua ll y select mat e s in definitive p l umage. But we do not know for certain if the y c hoose mates on the basis of plu mage or some oth e r indi ca tor of age. Subadult plumages clearl y serve other functions besides mate sele c tion. Com ell LaboratOt1f of OrnitholoBtt

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Chapter 3-Form and Ftm dion : Tire & ternal Bird Se)( Recognition T o a bird looking for a mate, knowi ng the sex of another indi vidual is key, but sex recognition also is critica l in numerous other soc i al interactions including b i rds defending terrltorres or mates. In species i n which t he sexes differ dramatically i n appearance, such as North ern Cardina ls, American Kestrels and Red-winged Blackb irds, males and females are easy to distinguish. Dif ferences between sex .es are more subtle in othe r species. I n many woodpeckers, for example, the amount of red on the head reveals the sex. I n the Downy, Hairy, and ladder backed woodpeckers only males have r ed on the back of the head. In others s u ch as the Red-bellied Pileated, and Acorn woodpecke rs, males have more red on the h ead. Birds undoubtedly use the same plumage cues t h at we do. I n Northern Flickers, for example only ma les have the black malar ( whisker ) stripe (Fig. 3-58). One researc h er (who probably also drew mustac hes on posters ) painted malar stripes on females and their mates chased them away (Noble, 1936)! When students work ing with a flock of California Quail dyed the p l umage of the fem a les to resemble that of the males the ma les treated their fo r mer mates as males. In species w1th similarl ooking sexes, ma les and fem a les seem to recognize each other by behavior. Note that birds do not require different p l umages t o recogniz e theoppositesex Abouthalfof all songbirds, for exa(np l e have similar p l umages i n both sexes. In these species, males and fema les recogniz e each other by behavior. Thls fact r eminds us that sexual differences in p l umage may arise fo r a var iety of reasons besides mate selection; rea sons that re l ate to the different ro les played by each sex-In cou rtship, nest attendance, a n d territorial defense for examp le. Individual Recognition To us, one Black-capped Chickadee or Yellow Warbler l ooks much like t h e next. O ccasio nally we might r ecognize a bird with a distinctive color abnormality ora missing feather and with mu c h work we can l earn to r ecognize individua l s of some spec ies, such as Downy or Plleated woodreckers, by differences in the patterns on the backs of their heads. Among wintering Tundra Swans i n western Engl and, researchers ca n distingu ish hundreds of individua l s mostly by varia tion s i n thei r bill markings. But individual recognition in most species rema ins a mystery to us--unless, of course, we have colorbanded or tagged b i rds for personal identificatio n. Many birds, h owever, clearl y recogn i ze other especial l y their mates. How? Birds probab l y identify familiar individuals the same way we recognize other peop le, by subt l e differences in color, head and body s h ape, facial features, posture, andvoice.Andsomeareverygoocl at this-a Nor thern Pintail can re cog nize its mate 300 yards away! Ha,dbook of Bird Biolo[jlf 3 67 Female Male Fig ure 3 -58. Northern Flick er M a le a nd F e m ale: Northern Flickers mal use tha b/,lck malar lw/lisker) stripe, found only on the m,J/e, to determine the sex of a bird When a researcher painted malar stripes o n femnles, their m ates chased them away! ( Noble 1936!

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3 f i g ure 3-59. M a l e and F e mal e House. Spar row: The blac k hib of the m a l e H o o se Sparrow, thought c o have evolved thr ollgl> $Biwal selection appears to act as an Indicator of mal e quality. Males with larger bibs are more dominant. hold better ter ritorii:>$ a n d copul a t e with f e m ales o ther th a n their maces more ofte n than do mal es with smaller hibs. Drawing by L. Ripper. Several studleshave demo n s trated that bird s us e co lor and pattern to r ecogn i ze individuals When Ruddy Tumsto nes-shorebirds w i th h i g hly variab l e p lumage-were shown model s that mimic ked the i r neighbors or str a ngers they reacte d aggressively o nly to the s tr angers ( W hitfi e l d 1 986), strong evidence t h at they could distingu i s h the m by appearance alone. In addition, several colonially nesting species, including Rin g-billed Gul ls, ca n pi c k their own yo ung from a "crowd'' of young by their f acia l markings. Flock Attr action Individuals of gregarious species s u c h as gu l ls, ga n nets swans, egrets, vu l t ures, crows, or blackbirds oftei1 locate other i n dividua l s or feeding flocks by sight. Mostofthesesp eciesareblac k white, or black and-white-conspicuous colors that show up well from a distance and may aid f l ocking (Savalli 199 5) Sexual Selectio n Throughout t his section we h a ve dis cussed how birds may use differe n ces in appearance to avo id mating with oth e r species and to recog nize eac h other in various ways. But the more we l earn about birds, t h e more evidence we find tha t s uccessfull y co mpeting for a mate within the s p ec ies may b e o n e of th e most important functio n s of dist i n c tive colors and pattern s ( But c her a n d Rohwer 1989 ; Savall i "1995) Well over a century ago, Charles D arwin r ec ognized t hat cer tain i n h e r ited traits s u c h as the gau dy plumes of a peacock o r t h e r ed epaulettes of a Red-winged Bl ackbir d do not n ecessari l y prom ote ind i v idi,Jal Instead t hese features improve a bird's chance of acquiring a mate and therefore in a population beca use more you n g arepr oc! uc.ed t hat bear th e advantageous tra its. Darwin gave t h is process its own name s e x u al s e le ctio n alt h ough it is in fac t a specia l type of natura l sel ection. Sexual selection can o perate in two related but dlstinct ways. Flr s t il ca n pro mot e tra it s t h at inc r ease a bird's ability t o compe t e with other member s of its sex t hus gai ning favor with or access to mates. As an examp le consi d er t h e b l ack bib of the male Hous e Sparrow, thought to hav e evolved t h is way (Fig. 3-59 ). R esearc hers hav e demonstrated that ma l e House Sparrows with larger bibs are mor e domi na n t hol d better q u a li ty territories, a nd chase and cop ulate with females other than their ma tes mor e often than males with small er bibs The black bib, by itse l f doe s not bnng these advantages, b u t serves as an accurate way for a male to visua lly s i g n a l his qu a lity to o t her ma les, without fig h ting. Presumably, males I hilt ca n avoid th e risk of In j u r y assoc i ated with fighting have an evolutio nar y advantage over those who m ust fight. Similarly, the red epaulettes of R ed-winge d Blackbi r ds p robably evolved because th ey g ive male s an advantage in male-male compeHtion for territories and females c h oose their mates on the basis Com ell of Ornitl1olo[j'l

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Chapter 3-Form aru:l Function: The External Bird of territory quality. A second way that sexua l selectio n can operate is by directly increasing an indMdual'sattractiveness to theoppositesex. Female House F inches choose mates with the brightest red co l oration and fema l e Great Snipes (an Old World species) choose males at least part l y by theamountofwhiteon their tails. We assume, therefore that these features-bright r ed H ouse Finch feathers, and white in Great Snipe tails-have evolved through selection. A trait may be attractive to members of the opposite sex for anumber of r easons, most of which are discussed in C h apter 6. However, directly related to p l umage cotor is the suggestion by Hamilton and Zuk ( 1 982) that birds in good health, or with fewer ectoparasites1 may be better ab l e to sport brightly colored feathers than are less hea lthy birds. Indeed, bright col o r s actually might have evo lved as a n honest indicator of heal th. Th erefo re, in choosing their mates males and fe males should select the more brightly colored individuals. A number of st u dies have supported the relati onship between health and bright colors. For example, in House Fin ches, males with brighter feathers are apparently in better nutr itional condi tion (Hill and Montgomerie 1994) and the colorful combs of chickens and wattles of turkeys fade i n brightness when the birds become s i ck (Stephen T. Em len, personal communication). Why don't birds "cheat" and produce colors or markings that advertise a higher quality than the bird actually is? In most cases, pro docingtheattractivecolors bears a cost which only birds of high qual ity can afford For example House Sparrows with large bibs may be cha l l enged by others with large bibs, and if they don t have the fighting ability they claim, they may be badly beaten in a fight. And unhealthy or otherwise poor-q ua l ity individua l s may be unable to spare the en ergy needed to produce and maintain brightly colored plumage. Sexual selection is most apparent when i t produces extreme and colorfu l plumages, which usua l l y occurs in species in which a few males mate with many different females as in peacocks and the gaudy bright-orange South American Cock-of-the Rock. But it also can ope r ate in species with the most common type of matingsystemmonogamy in w hi ch bfrds appear to form a pair bond with only a single mate. As researchers look more closely at these species, even sampling the DNA of you ng an d adu lts to determine the paternityofthe young, they are finding that ma les and females of many spec ies thought to be monogamous commonly copulate with individuals in addition to the l r own mates. In some cases, birds may use plumage colorati on as a quick way to assess the quality o( thei r potential consorts. Sexual se lection ca n even operate in species in which a single male and femal e truly do pair, as birds with more "attractive" plumages may acquire a better-quality mate or may be chose n earlier in the breeding season Sexual sele c tion i s discussed in g r eater depth in C h apter 6 We have now scrutinized the "outsides'' of birds from beak to loot. This close look has revealed how exquisitely natural sel ection has fine-tuned birds to meet the demands of their physica l and socia l env i ronments, from the way thatbarbules interlock on a hummingbird Handbook of Bird 3-69

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3 70 Georse A. Clark, Jr feather and spar r ows sputter abo u t during dust baths to the "snow shoes' of a Ruffed Grouse in win ter and the cryptic bwwn strea k i n g o n an Ame r ican Bittern. We do not know the sign ifi cance of every structure or color pattern we've consid ered and some may remain a mystery fo r ever. But the more we find out about each pattern the bet ter we understand how evo l ution works and why birds behave as they do. These are j ust some of th e reasons w h y bird s a r e s uch a rich a n d Importa nt g roup to study and e n joy e n d l essly Cornell L.aboratorlj of Omltholostt

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What's I nsicle: AnatomLf and PhttsioloBLf Howard E. Evans and} B. H e iser Much of the thr il l we experience watching birds is in seeing them fly, listening to their songs, d i scovering them at their nest, or simply watching them go about the ir dai l y rounds carfng for their p lumage and feeding. Rarely do we consider just how \he bird's body actuall y accomplishes these wonders. Exactly what are the various parts and pieces thalgo together to make a bird-and how do t hey perform, i n concert with o n e a nother, to produce the marvelous lives that give us so much p leasure? That is the subject of this chapter-the anatomy and physiology of birds. The subject is so vast that we can bare l y scratch its surface. The topic issomewhatsimplified because much oithe form and function of birds is very muc h l ike that of our own, four -legge(l terrestJial However birds do have senses and capabilities that we can onl y imagine, so d i fferent are they f r om ours. Most of the distinctive featur e s of avian anatomy and physiology are adaptat ions to flight: not only are birds ligh t in weight but the demands of flight make birds some of the h ighest energy users for their size in the animal kin gdom. Thi s energy powers flight ; heats a small easily cooled body; and supports the highly active life birds live even when not flying. While expl oring the anatomy and physio logy of a group of organisms, one often finds that the study of one specialized charaderistic leads to another and then to
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4-2 Cell H o ward E Evan s andJ. B H eise r tru e with birds, howev e r so i n t i mate l y are t h e i r a d a p tat i o n s inte r con" nect e d ; flight affects e v erything a b o u t the m Thr o u g bout th is c h apte r we will take a functi o n al a p p r oac h con ce ntr a tin g in eac h s e ctio n o n a n a t ornlcal struc tur e s with simi l ar functi o ns; these have b ee n g r o up ed t oget h e r i nt o fu n c tion a l syst e ms. As i n all l i vin g things, these syst ems a r e u ltimate l y compose d of cells t h e b asic units o f life Ce l l s w ith r ela t e d and o f ten ve r y simi l ar c h a r acteristi cs a r e agg regated t o form tissues. Tissues, ofte n o f quite d ist"fn c t ive c h arac t e r and fun ction, combine t o form d iscrete o r gans A g r oup of o r ga n s whose vario u s function s a r e coor d in ated to ac complis h o n e or m o r e of t h e basi c functi o n s of life i s r ecog ni ze d as a n organ syst e m F o r exa m p le ca rdi ac mu s cl e cells t ogethe r f o r m th e s mooth mu scle t issu e oi t h e h eart, whic h toge th e r w i t h h eart v a lves and t h e i nn e r an d o ute r cover in g of the heart, for m m os t of the heart o rgan. The h ear t b lood vessels and the b lood t o gether co n stitute t h e ci r cu lat o r y sy s te m ( Fig. 4-1). In thi s cha pter we discuss t h e impo rtan Hea t u res that are "in side" a bird co nsid e rin g th e internal o rgan syst e m s o n e by o n e t o u n d e r s t a n d t h e com po n e n t p a rts. Interact i o n a n d i nte grat1o n of these syst e m s a r e of vita l importan ce and a r e r e p eated l y p ointe d o ut. The fun c ti on of eac h syst e m (its p h ysio l ogy) is th en in ves ti ga t e d with sp ecia l attention to f l ig h t, r epro du cti o n and m eta b olis m ( en e r gy use). Th e syste ms-disTissue Organ Organ System CardiacM u scleCel!s -- Smooth Muscle of Hearl (Hearl Valves anrl Surrounding Membranes / HEART--... Con nective ITssue Cell $ --- Connective Tissue --.. (Ower LD)'ctive tissue, smooth muscle tissue, a n d epi t helium Together, these three cissue types make up t h e organs known iiS b l ood vessels. Another circulatory organ, the heart. is composed of smooth muscle t{ssueas well as heart valves ,1n d membranes. (The latter two compone nts a r e real/>' not Ussues or orgM1s, bot organ parts.) The heil/1, b l ood vessels, and blood fa liquid /issue composed of white and r ed b l ood cells together make u p the c i rculatory system. Corr lell of' Omith olo!Jtj

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Chapter 4Whats and PhljSiolos!J c ussed are: the s keletal system ; muscular syste m (excluding the skin mu scles that m ove t h e f e athers); nervou s sys tem including the sense orga n s ; endocrine system; circulatory system; respiratory system ; di gestive syste m ; and urogenital syste m The sk in a nd str u ctu res thalare produced by the sk in s u c h as feathers, col o r pigments, scales, claws, beak, waltles, and comb make up the integumentary syst em which was con sidered i n C h ap t er 3 This chapte r c oncludes w ith a look a t bird m etabolism. At the end of the chapte r is a tabl e s ummarizin g the major a n a tomica l differences between b i rd s and m a mmals arrange d by organ system. You m ay wish to ref er to th e table from time to time as a qu ick review of eac h system. The Skeletal The s keletal system compos e d of bone a nd car tila ge as well as associa t ed joints tendons, and ligaments, s upports and protects the soft struc tures of the body; provides for th e att
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4-4 Rock Dov e Howard E Evans andJ. B. Heiser But if too much calcium i s taken from the bones during eggshell for mation, the bones may become fracture-prone. Much of the del icat e balancin g act that makes possible both successful reproduction and the continued existence of the parent bird is co ntrol led by the e ndo crine system (see la t e r i n thi s chapter) arid it s regulation of calciu m metabolism, especiall y through the dynamics of livi n g bones. Two general features were acquired by the skE>Ieton of birds durtng the evolut ion o f Right. One is r i g i dity and the other i s lig h t ness (fig. 4-2). Rigidity of the skeleto n is the result of various fusions of n eigh boring bones, particularly partsofthevertebral column Consequently; b irds ( unlik e most ot her vertebrates) a r e notoriously stiff-backed As compensati o n they have lon g and highly moveable necks. Their body rigidity str e n gthe n s the skeleton for the stressful actions of flying and landing as wel l as running and jumping. Likew ise, fusion of the skull bo nes a llows the use of the beak as a lever or as a "hammer and chisel11 Weight Reduction Aided by Ughltveigfll /:Iones of Skull and Toothless Be11k Laq;e Keel on Sternum for AU.Jchmcnr of Flight Muscles Figure The Avian S kel e ton a nd its Adapt a tions for Flight : Most of the dis1/nctive features of a typical bird skeleton such as the Rock Dove ( pigeon / skel eton shown here are adaptmions fOr flight. Weight is reduce-d l>y hollow bones, 11 lightweight sku//, a toothless beak and ,;r reduced numbet.ofbones in the t;Jil and hand regions. Rigidi ty Is achiev6'!i through the fusion of many bones, including the pelvic region the hand, and portions oi the vertebr.JI wlumn. In adrlirinn, modified join t s allow tire wings to lock open providins rigidity at certain times during flight. Sltengtllls added IJy struts inside the hollow bones; backward-projeding, laterally flattened and ossif i ed caudal projections {Uncinate processes) on each rib thai overlap the adjacent db; and laf8e1 strong pectoml girdle bones which support the chest CiiVity-particu/arl y rl11ring flapping flight. Fin L./Vpper. Inset photo of R oc k Oove in flight by Marie l?eacL Cornell Lahorator'1 of Ornltholoti'1

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Chapter4-What's Inside; Anatomtt and PhtjsioloBtl as in woodpeckers. (How the woodpecker protects its brain from the vio l ent impacts of 1ts hammering is still an open question.) Lig h t ness comes from cavities or spaces that deve lop within almost all bones as a bird grows. These spaces con n ect to the respi ratory system and thus conta i n a ir We cal l such bones pneumatic ( noo-MAT ik) and speak of the s k eleta l system as being pneuma tized Because they are.fille d with airspaces and not bone and marrow, bird bones are l ighter in weight than s imilar -sized bones of other vertebrate g r oups. For example (Fig. 4-3), a male Mallard and a mal e mink 111ay both weigh about two a nd one -half pounds Gust over one kilogram) and be nearly the same l engths ( not cou ntin g the tai ls), but they appear quite different in "size"-the duck has a much greater volume. T he bird's l owe r density is due in part to t h e bird's h ollow bones. Actually 1heskeletons of the two a nimal s are ver y s imilar in weight (about2.25 ounces 160 to 65 grams I when clean and dry). But almost every b o n e of the bird is larger in some or a ll dimensions, w ith more surface area (or muscle attachment. The airspaces in skull bones arise from nasal passageways, where as those in t h e vertebrae, stern um ribs, pel vis humerus, and femur are connected to either the air sacs or the lung s directly tsee Fig. 4-82b} The largest a nd most effide nt flying birds, such as the a lbatrosses and frigatebirds, have interconnected air spaces passing from the humeru s to t h e tips of the digits across all ofthe join t spaces. In contrast, a pen guin, a flightless bird that swims w ith its s hort but powerful wings s il much larger volume ;md thus lower body densitY, due in part to its lightweight, air-filled bones. I

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4 I Howard E. Evans J. B. Heiser sw ift s that fly fast perhaps to allow the head to be smaller and mor e c ompact as a n aid to streamlin in g Other fastf l y ing birds suc h as shoreb irds, also hav e red u c ed pneumatization. Extensive skull pneu ma t ization is also decreased in so m e birds that dive from the air into water, suc h as terns and kingfishers and in woodpeckers that "hammer'' wood with t heir bills and need very strong skulls. Another distinctive and uniquely important tissue of the skeleta l system i s cartilage the same tissue found in human joints. Cartilage like bone, is a ti ssue with living cells embedded in a nonmineralized matrix capable of growth or resorpt i on as well as transformation into bone. In the growing bird emb ryo the initia l skeleton entire l y of ca r tilage ossifies (becomes bone ) very rapidly around the time of hatching and continues ossi f ying at a slowe r rate throughout life. A similar se quence occu r s in other verteb rates, including humans. Bone also can be formed directly i n tissues without going through a carti l age stage. S u c h direct ossificatio n is seen in tendons of the hind-limb muscles in most birds, and is familiar to aficionados of the turkey drumstick. Tendons, which con n ect mu scles to bones, and ligaments, whic h connect one bone to another ac ross a joint, are soft, pliable, and above all elastic tissu e s when they are not ossif i ed. The} have few livihg cells and a restri cted blood supply whic h exp l ains why they he a l from I n jury so slow ly. By conventi on the skeleton is divided into an axial ske l e t o n and an appendicular s keleton The axia l skeleton consists of the vertebral column of the neck, trunk, and tail, and the exq ui s i tely c omplicated skull, w i th its associated hyoid apparatus ( the suppo r ting framework of the tongue). The appendicular s k e leton consists of the sternum or breastbone the pectoral gi rdl e with wings and the pelvic gird l e with legs. Shown in Figs. 4-4, 4-5, and 4-6 are the articu l ated ske l etons { that is, the bones a r e joined together as they would be in life) of a domes ti c c hi cken, a Budgerigar ( a type of parakeet ) and a Golden Eagle. Y ou may wish to remove these pages a nd keep them readi l y at hand while r eadIng about both the skeletal and muscular systems. The chicken has its wings extended as if it were about to take off in flight. This is the standard position used in mounting or illustrat i ng a bird for anawmical study The parakeet has its w ing s folded in a normal perching position, a nd the Gol den Eagle has its left wing lowered and pu l led s l ightl y away from the body. Referfo these drawings frequently as yo u proceed in you r reading; they wil l o rient you tot he parts being d i scussed. You will note differences between the three species 0fbirds il l ustrated. The ske l etons of all bird species differ from one another in ways that are not apparent externally but are often sign ificanl to evo l utionary and systematic ornithologists. If you have at hand the actual ske l e ton of a bird or eve n some i solated bones, so much the better, for you will be able to see how they appea r 1n three dimensions. ( Perhaps i t would be useful to plan on a whole ro ast chicken dinner before read i ng furlher! ) Cornel/l..Qboratortt of Ornithologtt

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Chapter 4What's Inside: Anatom11 and P htjsioloB'f 4-7 Cranium Unc in ate Process Pubi s Figure 4-4. Skeleton o f the Chicken: Viewed from the l en side the c h icken skel eton is s h own wit h the J ell 1Ving raisttd over the body. Compar e wnh Figures 4._s and 4-6, in wilich different bird species in difii.
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I 4 Howard E. EvansandJ. B Heiser Figure 4-5. Skeleton of the Budgerigar: The 5keleton oi this Budgerigar {a species of parakeet) is viewed from /he left side, in a normal perching position, with the /eli wing folded against the body. In this view the clavicle and coracoid we /,;dden by the folded wing, but notice the large keel on the sternum indicating that the bird is a strong, t7yer. Note too, the relatively small pelvic girdle and lessdeveloped leg and foot bones-
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Chapter4-Wlults Inside: Anatomtt and 4-9 Scapuli! Carpometacarpus Figure 4-6. Skeleton of th e Colden Eagle: This skeferon is viewed at an angle : from t/ 1 e rea.r ilnd slightly to the left side, and from sumewhat above The feel are not shown The lett wing is lowered and pulled away from the /.Jvrlvslightly, t o demonstrate the great mol?llity of the p ectoral girdle (see Fig.4-16). Notice the massive wins anrlleg bones, evidence that It is a powerfol flier with equally powerfollegs used (o capwre Its prey. T h e robust skull wit h its massive hooked beak is ) et another acf
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I 4 F igure 4-7. Age-relat e d Changes I n tir e Ossitication and Pneumatization of the Passerine Skull: The cranium of a newly fledged passerine is composed of a single layer of cartih1ge and bone. As the young bird ages, a second layer develops under the llrs4 the two layers being slig/Jtly separated by air spaces and ioined by small columns of ossifying bone. The development of these lay ers is called s kull pn eumatization a,nd is followed b y full ossif ication, usually complete by the time the bird Is one year old. Althou gh there is variability amonc species, the process typically follows one of rwo patterns. In the peripheral pattern pneumalization develops from the outer edges of the cran ium inward, \vhereas In the median line pattern pneumatization starts along a centra( line and develops on both sides of the cranium si mvltaneous[y. l)npne um a tized areas of a passerine skull appear pinkish In colo r where.1s pneumatized a reas appe;lr grayish or whitish and de velop smalll'l hire dots .15 the bon y col umns ossify. I f the head feathers of a bird in the hand ate parred to the skin overlying the sku!& the degree of skull co l oratio n m,,y bl:' visii1/e. Experi e n ced bird bar)ders use skul/ ossification and pneumatizc11ion to reliabl y determine the age of passerines captured in the fall, a (echniqu e knovvn as si(U/Jing. Ada pled from Pyle eta/. (1987 p. 9 ) Periphera/1 Pattern "'-':\ Howar d E. EvansandJ. B. Heiser Entire cranium pinkish in cole>r Entirely t.mpneumatized Fledglings (JuneJuly) ""' Median Line P.mern t.arge pinkish Jteas small gr
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Chapter 4Wfwt's lnside: A n atollllf and Pht.tsiolo!jtf a Dorsal View Cranium l1. L atera /View Ct'allium The skull (Fig. 4-8) i s composed of a brainc', is f'Omposed of several bones liM/ are so c:ompl ele l v lirsed in the c1dult1Jird rhatthe boundaries orsutures, between them am n() longer visible NDticc the largeor b itsin which thee)esreside The skeleton of the upper be,lk consists of thf' nasal region the n ostri ls, ,1nd the fused premaxilla ry hones. upper beak connects to the rest of tlw skull a r the t1exible cra niofa cial binge talso called tire n well as the ear openirrJ::s. which a r e slight/)' ""'/ W>n(r;llo I he orhits. Cnmpare rhi s view In thatfJfthe chic/am in Figur e 4-9. t\llost obvious isl/le differ-ence in S'hape l>etween the pretl]a;.:illa I ilnd denr ar y bones o( the two species. The BudgerigJr l1.1s J wong hooked heal. tvpical oi and parakeels, used lor rracking hard seed., whereds rile chit ken has & stmight srout beak for peckinfi ot (oodon thegrouttd. Drawings from Evans (19961. Ear Opening

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I 4-12 Figure 4-9. The Avian jaw and Cranial a. Opening the Jaws Kinesis : Sf,own lmre i< I) l;tteral view or a c hicken skull, Theprema .villary bones of the upper articulate with the era-Prema'!illa nium at the flexible craniofacial allowing the upper jaw to move 111 the same time as lhe lower jaw-a process known as cranial /linesis. The bird's low er jaw co nsists of left and right dentar)' bones fused ac their tip. nle lo ver jaw is linked to the upper jaw via the arti cular bone and the adjacent quadrate bone which pia)' an essent ial role in cranial kinesis. a. Ope ning the jaw s : The pro cess of Iliff opening begins when a set of muscles acrs co clrop the lower jaK As the lower jiJw moves dowmvard, t/1e articular bone applies pressure on the quadrate bone causing the quadrate ro 11. Closing the jaw s rotat e such th.ll its lower surface moves Forward. As it moves t h e quadrate pushes a.sainst tw o sel$ of bony rods, the palatine and the jugal arch which push aguinsl the premaxillary bones, raising the upper Jaw wh i le rho lower jaw is being depressed. b Closing the jaws: To close the bTl/, another set ol muscles depresses the pre m a ,vi/lary bones while it raises tlw lower beak. Adapted from King and McLelland ( t97 S p. 17). A merican Woodcock Cornell L:iborat"orq of Ornitholo8'1 Howard E. E vans and J. B. H eiser Figure 4-10. Cranial Kinesis in Action : The upper ;aw of birds, unlike t/1e upper jaw of humans is capablenfmnvemen t giving the beak a pincer-like motion known as cranial kinesis (see Fig. 4-9) The degree to whrch cranial kinesis oc curs in vario u s species is related tn their feeding habits. In/h e Ostrich a grazing bird, cranial kinesislspoorl y developed: to feed on grasses anrl other vegetation this species does not need to o pen i t s beak wide. In contrast the American Bittern has co n siderab l e kinesis open ing its !?eak wide to seize a frog. In the American Woodcock, movement i s g reat est at the tip of the beak, allowing the bird to grasp earthworms while the beak is immersed in soft soil. h)' Charles L. Ripper.

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Owpter 4-What' s Inside: Anatom11 and Ph4siolo94 4-1 3 beak and lower beak when refer ring to the i n tact, living bird. a. V entra l View of Rock D ove Hyoid A p p. 1 r a t u s The lower jaw articulates with the moveable quadrat e bone on each side of the sku l l; this articulation allows the n1outh to open widely ( Fig. 4-9) Because the quad rate bone can also pivot forward at its ar ticulation with the sku ll it allows t h e lower jaw to be protruded while the upper jaw is raised by extreme extension at the cranio facial ( nasal-frontal ) h i nge. One set of mus cles attached to the q u adrate, cranium, and lower jaw opens the bill by s i multaneously lowering the lower beak and rocking the quadrate forward, forcing the upper beak upward Another set of muscles closes the bill by depressing the pre maxillary bones and at the same time raising the lower jaw. This flexibi lity of the Jaw joints, wh1ch al lows the upper jaw to be raised at the same time that the lower jaw Is depressed, is ca l ied c ranial kinesis. Movement of the bird s vp per jaw contrasts sharply with the fused im mobility of our upper jaw in re l ation to the rest of our sk ull, and is associated with the forceps-li k e f u nctioning of the beak to grasp food ( Fi g. 4-10). No living bir d has teeth, a l though several birds parti cu lar l y fish eaters such as the mergansers have serrated bills. Teeth (Structura l l y like those of o t her vertebrates) were present1 however in th e most ancient Jurassic birds of Bavaria such as Archaeopteryx, and continued to be present in Cretaceous birds of North America, s u ch as Hesperornis and lchthyornis. T hese ancient teeth are but one of the many characteristics that birds inherited from their ancestors. Through natural selection birds subsequently discarded teeth in favor of the lighter bill. The largeorbitorcavityfor the eye is so deep that the eyes almost meet on the midline of the skull. Only a thin, sometimes i ncompl ete, i nterorbital septum separates them. Aside from the beak, the orbits are the most prominent feature of the bird skull. I n Figure 4-8 notice how the orbits crowd the braincase backward. The ear o p ening lies close to the lower r i m of the orbit on each side. In owls, the open i ng to the ear is at a slight l y different level on the right and left sides. This asymmetry allows for a more accurate pinpolntf ng of the direction of a sound source by increasing the disparity in arriva l times of a sound at t'he two ears (see Fig. 4-47). Hyoid Apparatu s Between the two halves of the lower jaw is the h yoid apparatu s a series of articulated bones that support both the tong u e and the muscles that provfde for tongue movement ( Fi g 4-11). Handbook of Bird Biolo94 Cartilages of the LJrymr F igure 4-11. The H y oid A p p arat us: The bones ilnrl cartilaginous structures form ing the skeleton IJ{ the tongue ate collec tivel y t ermed the hyoid apparatus. Muscles attached to this compound st(l)cture axlend and retract th e tongue. a. Ventral View o f Rock D o v e Hyoid A p paratu5: Not e 1he IWO hyoid h orns each r;a mposed of two bones 1vhich extend backward from the tong u e b one and continue beneath the skull, curving VPI"arrf i!fDUIJd the back of the heiJd in some species. Drawing by Charles L. Ri pper. b. L ateral View of Budgerigar Hy9id Appa ra ( us: The length of the hy oid horm varies con side rabl y among species. I n 1he Budgerlgac the horns are shore indica t ing that these birds use tileir tongues to manipulate food within the mouth rather than extending th e t ongue to feed Tl1e tongue bone itself may be speaPshaped as in the Rock Dove; blunL as In the BudgerigiJr ; or ilexible, t15 in humminf:jlllrds ; the differences reflec t the different s tru ctures and f un c tion s of' th e tongue. Thl' hyoid appilratus surrounds ,llld is atlilcl1ed to the larynx Adapted from f:wms ( 1996 )

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Figure 4-12. The Hyoid Apparatus and Tongue Protrusion in the Northern Flicker: /tr woodpeckers, a highly pro trus lble tOIII:iue Is an essential foodgatlt ering tool Many woodpecker species drill h o les i n dead trees and then probe with their t o n gues for insects. Others s11ch as the Northern Flicker illustrated here. feed o n the ground, using their tongues to extr.1ct ants from su bter ranean tunnels. Woodpeckers have elongVirh elaborate musculature enabling t h em to greatly ext end rheir tongues--in some species up to (our times the length of the b ill a. Tongue R etracted: The long, s l ender hyoid horns are s h eathed b y muscle for most of their length. Anchore d by mus cles in the lower beak the horns run sepi!rotel y on eit h er side around the back o( the head o ul!;id e the skull the n together enter the right 11ostri/ ( see dorsal view), a tt aching to lhe ske l eton of the upper bea/1. b Tongue Protruded : When the muscles of the sheath conttact, the hyoid hom s are sq u eezed lnr.o ti ght contact with the skull a nd pushed forward, pmtwrling the t7icker's tongve from its mowh. Adap t ed from drawings by Charles L. Ripper. Howard E. Evans andJ. B Heise r Th e term ''apparatus" is a collecHve n a m e for oil the bones and ca1li I ages that composeth i sV-s hap ed s tru c tur e. The muscles attac h ed to the bones of the h yo id ex tend and retract the t o n g u e. In Fig ure 4-11 b note that each h orn of the hyoid fs corn posed of two bones that extend backward ( caudally) b e neath the skull and then curve around the back of the head. The horn s a re p a rti c ul a rl y long in woodpeckers and other birds that ca n extensively project the tongu e ( Fi g. 4-1 2). The Eurasian G r ee n Woodpecke r has t h e longe s t h yo id h o rn s for its body size, and presumably ca n extend its tongu e the f a r thest. Short h yo id horn s1 as in p a rr o ts, indicate that the birds use the i r tongue to m anipulate food within t h e mouth rath er than extending it to co ll ec t food In birds that ea t worms a nd g rub s the bone that supports the tongue-calle d th e to n g ue bone or e n tog l ossa l-may b e spear-shaped, and the integu mentar y portion of the tongue m ay bear spines; in birds that manipulate seeds or fruits, the entog lossal i s blunt and padded by the tongue tissuei a nd in n ec tar feeders1 i t is flexib l e and cove r ed b y a bru s h-like t o n gue. More will b e s aid about the tongue in the discuss ion of th e digest iv e system Ve r t e b r a l Column The ve r tebra l co l umn, commonly ca li e d the "backbone/' is nota single bone b u t a s e ries of co mplicated unique l y art i c ulating or rigidl y fused vertebrae (sin g ul ar ver t e b r a ) that var y in numbe r a m ong spe c ies. As in oth e r verr e brates, the verteb rae a r e named by reg i on ( and a. Tongue Retraded 1-fyaidt"iom Sheathed In Muscle b Tongue Protruded Cornell ofOmitiJOiom Tungu e

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Cilapter 4 What's Inside: and a. Lat e ral View of Cervi cal Vertebrae HEAOOFBIRD Cervical V erte bra A b Ends of Cervical Vertebrae Anterior Centrurp End of Next Vertebra "' Posterior Centrum End of One Vertebr.J Cervica l Vertebra 8 ., PosteriorCcmtrum End: ( Concave Dorsoventrally Ante r ior Centrum End. Concave L aterall y c. Coupling Me c hani s m Cervfcnl Vl:rlebra A .. .... Cervi c al VerteiJr;J 8 4 TAll O F B I RO F igure 4-1.1. Cervical Vertebrae and Flexi bility of th e B ird Neck : Birds iilre well known for the flexibility of their necks, facili tated by having a large nwnl1er of i nt erlocking cervi c al vertebrae that C (nlddle -shaper/1 In a lilteml direction wl1erflas the posterior end of the c entrum is con cavP in a dor.;o-ventrol direction (see b/. This condition ofrhe centrum ends is t ermed hetero coelous. ( Note chac1he verlic-
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I 4 H oward E Evans and J. B Heiser unique among livi n g vertebrates, a n d immediate l y iden tif ies isolated bird vertebrae. The f irst cer vical vertebra, termed the atlas i s and a rti c u lates with a p r om inent protrusion the occipital condy le o n d1e base of the skull (Fig. 4-14a). The atlas is named for the d i vin it y f rom Greek mythology who supported the sky, i n all u s ion to the vertebra's support of the skull. U n iquely the atlas has a hol e or notch on the ventral s ur face of its central opening (th e vertebral canal} into whic h the peg-like dens of the second cervica l vertebra, the ax is, f its. The dens, which embryo logical l y as part of the atlas, is attac hed to the skull by a ligam e nl. Thus, as in all terrestrial vertebrates, the first two cervica l vertebrae, t h e atlas and axis, are highly modified for the articu lation of the skull wit h the rest of the vertebral column. The remaini n g cerv ical vertebrae have e i t her short, f used rib r emnants (fig. 4-14b) or may a. A tlas and Axis of Rock Dove Fisure 4-14. T yp e s of Vertebrae: a Atlas an d /\xis of Rock Dove: The cervical vertebrae, forming the neck, var y in number among bird species. The two cervical vert ebroe closest to the head are .
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Chapter 4What's Inside: Anatomtt and Phttsiolo911 b. Cervical Vertebra of the C h icken, Lateral View c:. Thorac:l<; Vertebr,1c and R ib Altac:hment Fused 2nd-5th Thoracic Vertebrae (Notarium) ANTERIOR c/. T()e Fit3t through S i xth Thoracic Vertebrae of the Chicken t \NrRIOI? POSTERIOR c2. Lateral View of Three Thoracic Vertebrae of the Rock Dove witl1 RlbsAtt.Jched Facets lor Rib Attachment Vertebral Rib POSTERIOR DORSAL VENTRAl. d. Anterior View ofn1oracil Vertebra of the R ock Dove with Rib Ar(ached Handbook o( Bird 4-17 I

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4 Howard E. Evans and J. B. Heiser bear small moveab l e ribs. In either case there is an openfng between the vertebra and !he base of eac h of the forked ribs. When cervi c al vertebrae bear moveable r ibs, they a r e d i fficu It to d isti ngu ish from tho racic verteb rae, and t h e term "cervicodo r sal" vertebrae may be used. If the rib articulates with the sternum, either directly or by a l igame nt it is considered to be a thoracic vertebra. Thoracic vertebrae ( fro m t h e tho rax or chestregion ) can be dis tinguis hed from othe r ver tebrae by t h eir facets for rib articu l ation (Fig. 4-14c). They a lso are character ized by we ll -deve l oped spines ( spinous processes) on their dorsal s urfaces for the attachment of deep back muscles. Most bi rds have between fo ur and six thoracic vertebrae; the Rock Dove has five. Some of the t h oracic vertebrae may become fused wit h one another to form a ' not a r ium' for added rigidity of the b(lckbone, a benef i t in f l ying and l anding. In Figures 4-6 and 4 -20 n ote thesy nsacrum anot her ture of the bird's vertebral col u mn. I t consists of a fusion of a variab l e n umber of thoracic ver t ebrae with all of the lumbar, all of the sacral, a nd the f i rst few caudal vertebrae. This rigid segment is i n turn fused on eit her side w ith the ilium bo nes of the pelvis. The number of vertebrae involved in the bird s synsacrum var ies among species from 10 to 23. T h e tail of a bird co nsists off rom four to nine free caudal vertebrae and a terminal bone called the pygost y l e formed by several fused ve r tebrae (see Figs. 4-4 to 4-6). The pygostyle is the shape of a p l owshare and provides attachment for the fli ght feathers of the tail. On top of the pygostyle rests the o11 g l a nd. The ribs, together with the thoracic vertebrae above and the sternum be low, form a bony thoraci c cage ( r ib cage) enclosing the heart, liver, and lungs, as well as the thorac i c a ir sacs (Fig. 4-15). Each thoracic rib has a dorsal and a ventral part with a hinge between them The upper or vertebral rib a rt icu lates with .a thoracic vertebra; the lower segment or s ternal rib articulates with the sternum This hinge d arrangeme nt allows t h e thorax to be expanded and compressed for breathing, and thus act as a bellows. The sternum moves downward a nd forward for expansion during inspi r ation then upward and back ward for compression dur ing exp i ration. The pattern of inhalation and exhal atio n while flying may be quite different. During flight pectoral muscles spread the furcu l a a n d thus participate in b r eath i ng (see F ig. 5 5). Projec ting caudally from the vertebral segment of each rib is an uncinate process that overlaps the rib behi n d it and h elps to str e n gthe n t h e rib cage (see Fig. 4-5} ("Process," i n the a n atomical sense, means a projection or extension from a bone ; unci nus is Latin for ' hook.") Appendicular Skeleton The a ppendicular s keleton consists of the bemes o f the w ings a n d h ind limbs, togelher wlth thelr supporting pectoral and pelvic g irdles, and the sternum wh ich artic ulates wi t h the pectoral g i rdle as well as w ith the axial skel eton. Cornell Laboraton1of' Orni tholow1

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Chapter4 -What's Inside: Anatonu1 and Unci n ate Process Pectoral Girdle Locationoi He level of the fi r sttlwracic The thomc:ic cage consists of t h e ribs connec.ted to the thoracic vertebrae above Mld to 1/Je sternum !breastbone ) below. II forms a llexible but s r rong protective enclosweforchebird's heilrt, liver, lungs, and thoracic air sacs, Each rib consist s of two hinged section!;, the upper vertebraf rib and tilt!' lower sternal rib. The h i nge allows the thorax to expand and contr.Kt durins flrf'athing Fmm each vertl;'bral rib an uncinat e process projec/5 hack ward nverl,lpping the rib behind it and thereby s tr e n gthening the thoracic 01ge. Notice the latRf! ilfli!a created by the kt-'81 (c,lffna} of thE' s ternum, which i:; the site of attachment oi the powerfu l f light The spinal cord is located i n the vettebral Cnal a tube" for m ed by the openings oi success-ive l 'ertebrae. Adaptc..-d from (1996).

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4 Fi g ure 4-7 6. The Avian Pectoral Girdle: ThepectoralgirrileconslsiSofthreebones sc.1pula,. and the cor;tcoid.ln most birds a s fn the Rock Dove pidured here the cl.wic/cs are fused to form the V-sh.1ped furcula or The scapula and comcoid meet to form a cupshaped depression, the glenoid fo .o;.<;a, w h ich receives the rounded e n d or the hu merus lom1 ins a balland-socket joint th.Jt enables the humerus to rotate freely .1round t he shoulder joint. The upper end oft he coracoid articulates with the clwlcle as well as with thf' scapula, and at thisthrf'f'oiVJ Y joint is an opening tem1cd tire foramen lriosseum (a/so known .1s the triosseal canal or supracoracoid foramen). Through this opening p.1sscs tire tendon of the suproc:oracoideus, a powerful flight m uscle that raises th e w ing (see Fig. 5-G) n1e lm-ver drawin g s hows t h e positio n ofthepectoMI girdle (shaded areas) with i n t he skeleton ol a Colden Eagle, seen in postetiolatcral view, with the left wing lowered mle furc ula is not visible .) This view Illus trates that the only bone-to -bone ronn ection between the pectoral girdlefand h e n ctthe wing) and the .1xial s kel eton is the junction between the base of each coracotd .mel tlte sternum. Further conn ee lions iJre provided by muscle s that /loltlth e sCJpula in place agains t the rib ca ge This arranRement c reat es a (ret.' floa ting" pectoml girdle, allowing 1/r(' extreme mobilit y so essential to fliMh t M.1in drawing reprinted from Ma11u
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Chapter 4What's I nsicle: a11d Phttsiolo[jtl pu ll i n g oppositely o n the w in g du ring fllg ht. The broad base of each coraco i d b o n e fits into a g r oove on the cranial e n d of the sternum. At its oth er end, the co r acoid meets the scapula at t h e s h ou l de r joint to form a shallow depression the g l enoid fossa, with wh i ch the base of t h e w in g articu l a tes. The uppe r end of the coracoid bone articu lates n ot o nl y w ith the scapula, b u t a lso wi t h the clavicle, f o r ming an ope n i n g a t the t hreeway joint throug h w h ich the t endon of a powerf u l flight m uscle passes. Thi s s upracoracoid (meanin g ''to go above t h e coraco id") muscle raises the w ing, t h e open ing, called the fora men triosseum or supracoracold foramen, serves as part of a pu ll ey system a l l owi n g the downwar d f orce of t h e contract ing supracoracoid muscl e to be r edirected to an upward p u ll o n t h e dorsa l surface of the win g (see Fig. Bones ot the Wing Evolution has modified b ird forelimbs (Fig. 4-1 7 ) by reduc i ng the num ber and le n gth of the bones that correspo n d to those of our pal m (metacarpa ls) and our f i ngers ( d i gi ts-made up of phalanges ) The wrist has been reduced 1 0 two carpa ls, the radi ale a n d u l nare, by formation o( a fused carpometaca r pus in w h ich several of the wrist bo nes have bee n fused with som e of t h e palm bones. All fly in g bfrds Bird Hum a n Digi/3 IMitwr Digit / 4 1 17..The Bones of Human and B i rd FtJre limb : The forelimb of a t'lylng bird and,, human
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4 Figure 4-18. Wing Spurs: Spurs are outgrowths th a t may occur
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Chapte r 4Wl1at's Inside: Anatomtt and Phttsiolotjlf Ratit e : E m u Carinate: Rotk Dove Sternum with Well -deve l oped Keel a fact s tron g l y indicatin g that their a ncestors c ou l d f l y (see Ch. 5, Loss of F l ight). I n pengu in s the bones a r e simply s h o r tened ilatten ed, broadened and generally strengthen e d into paddle-li ke flipp e r s suit ab l e for flight underwater. Amon g th e r alites (see Fig. 5-48) the wing bones hav e degenerat ed in both s i ze and strength especially in the kiwis of New Zeal and w hose w ings a r e m ere s tub s hidden beneath the feathe rs. St e rnum The st e rnum o r breastbone of all flyin g bird s has a midve ntral k e el o r carina to w hich the p ecto r al b reast muscles attach (fig. 4-1 9). A general term for birds with a keel is quina tes, The rel a tiv e size of th e keel i s directl y corre lat e d with t h e deve l opment of th e pect oralis muscle, which pro vi des. power for the downwa rd wing stro ke pro p ellingthebird upwa rd and forw a r d in fli ght, Thereforeon ecan j udge, by looking at a bird s sternum the r elative d eve l op m e nt of its p ec toral muscles a n d consequ e ntly its flyi ng ability. A hummingbird has th e l a rgest kee l of any bird relativ e to its body size, and i-s tr ul y the "king" of the carin a t es Its f l y in g ability is no surp r ise. The sternum of l a r ge f l ightless birds such as the Ostr i c h Emu, rhea and cassowa ry, as well as some others isfl. a t and plateor Suc h birds that lack a keel are often co l l ectively spoken of as ratites (fro m the latin for raft or fl at-bottomed boat), but thi s term m ay l ack taxonomic o r evo l utfona ry H andbook of B i rd BioloB'I 4 .23 Figure 4-19. The Sternum in a Fly ing Versus a Flig!Jtless Bird: In flying IJirrls, t he s/ernum h8:5 a midv entral keet or mrina-a ridge o( bone that projec t s out from the s ternum and to whic/1 the pectoral flight mu scles attach. The size of the keel is close/)' related to the siLl!' oft h e pectoral muscles and tiiUs r eflects thebird's flying allllity. Birds with a kref, web as the Rod Dove (inserl, ure t ermed carinales In f/lgh(less birds. such us the lirnu s h ow n here the Is small and shape d like a very shallow bowl. It complme l y a midvcmral ktJI.'I, reflectincthe r ed u ced .1nd poorly developed pectoral muscles ,Jssociated with the bird's (lightlessness. Birds lack ing a kee l are termed ralites. Note r h.11 in both dmwi ngs, mrrespnnding parts of the (thar is I hose not includi ng/h e keel) a r e stippled. Emu reprinted I from Manual of Ornithology, L>y Noble :S. Proctor and Patrick I Lynch witll pe-rmission of the publisher Copyright 7 993 University Press. Inset dr,;w. ing h)' Charles L. Ripper.

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Rock Dove Free C;wda I Ve!tebme figure 4-20 The Avian Pelvic Gird le: n1e pelvic girdle s i 10WII above in dorsolateral co nsists of three bo nes 011 eac h side of the body: lho ilium ( plural: ilia), the ischiu m and the pubis. Theil ium forms the cranlnl and lateral part of the gird l e and is c;umpletel y fused with the ischium, w!Jich the lateral part The ilium has a cup-shaped d ep r ession (Or the attachmen( of (he ( upper leg boru!), The Ions. thin l)u/Jis runs backward .1long the outer most edge of the ischiut n In 1/1e p elvic region, !he vertebrae are fused into the r;g;d synsacrum consisting of a few thoracic vertebrae all the lumbar and sacral vertebrae, and the first few caud al vertebrae. n,e Fila a r efused with thesyn sacrum on either side oft he bird's body, forming a stro n g but lightweieht stwc ture for /he al/ac hm e nt of the muscles oi tl1e legs, tail, a nd.lbclomen, and provid ing prot ection for the ,1bdon r irml orgaos. The right clrawing shows the location oi the pelvic girdle a11rl synsacrum within the skeleton ola Golden i n dorsolrl!eral view. As a demortslriltion of how t/1e lorm of the pelvis is influe n ced b)' ftmct fun, c ompare the size uf the pel vic girdle of the ground-dwellitlg Emu (Fig. 4 -19) with that ola flying bird :such is /he Budgerl8llf (/ilg ot-5). The huge pelvic gird l e is evidert<:e that legs, not are its me11ns of transport. Rock Dove pelvis by Charles L. Ripper. Right drawing adap t eel from Proctor ,Jild Lynch (199), p. I 391. Ilium Howard E. Evatrs and J B Heiser Loc ation of the Pelvic Girdle and Synsacrum in the Skeleton of a Golden Eagle signifi cance because it is un c lear w hether these b irds are closely re lated. The la c k of a keel o n t h e sternum of A rchaeoprer yxprompts som e paleon t ologists to assume that thi s ancestral bird glided from e l evated perc hes, and was in capab l e of flapping f l ight. Pelvic Girdle T h e p e l v i c g i rdle o r p elvis (fro m the Latin for ''basi n ") is formed by three bones on each side of the body: the ilium, i schium (ISK-ee-um), a nd pubis (Fig. 4--2 0 ). The right a nd left ilia a r e f used to the series o( fused vertebrae of that region, the synsacrum to for m a rigid support for each hal f of the pe l vis. In a ll birds except rheas, the pe l vi s is ope n below be.cause the right a nd l eft i schia a n d pubes do n o t meet. In female birds this open pelvis facilitates the layi ng of eggs that a r e large r elat iv e to the s ize of the par e nt. Bones of the Hind limb The hind limb like the fo r elimb, Is composed of a series of bones arti cula ted end t o end (Fig. 4-21 ) The femur or thi g hb one i s relatively s h ort in a ll birds and is usu ally less than half the length of the next bone fa11her down the leg (the tibiot a r s u s ) in large wading birds. The small head ofthe iemu r fits deeply Into t h e h i p j oi nt's socket or acet abulum. At the lower e nd ofthe femur the p a t ella or kneecap (an ossification in a t endo n ) glides i n a deep g roove and adds stabi lity to t h e knee joint. When the knee is be nt the pat ella raises the tendon away from the kne e joint. This increases the tendon's angle of p u ll o n the lo wer leg, makin g the p ullin g muscle's actio n m ore effective The tibi ot a r s u s ( drumstick bone ) is usu ally the bird's l o n gest leg bone. I t is co mposed of the tibia fused at its outer ( distal) end with the proxima l tarsal (ankle) bo nes. Thespllntl ik ebone a rt ic ulatin g with the lateral condy l e (a process) at the dista l e n d of the femur is the fibula, w hose distal e n d (nearest the ankle) does not ossify in birds. Cornell Laboratortt of' Orn!tholoBtt

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Chapter4 Whatsln side: Anatonu1 and Phalanx with Attached '-.... Bird 1 (/-fa /lu x/ Figure 4-21. The Bones of the Human and Bird ( Left) Hind Limb : The legs of,, bird a nd hum an are compar ed Iii demo n strate tl 1 e cnrrespondent e h e tween the Tl1e wpper lttg of the bird ret;embles that ui the human i n basic structure, illthoug h the l e ngth s of the bones dif(l:'r. For instance tile femur or thig hh one is rel.7tive l y short I n b irds, and the fibula is mu c h reduced. The tibiotarsus consisting of the tibia fused to the first few ankle (tarsal/ l:iones, may be ver y lung in some wadi n g birds The bird's lnw e r leg ,md t'ool have been greatly modified thr oug h natural s elec tion The elongat ed larsomef.a lars!Js is made up of fused metatarsa!IJunes(tlw sole of the foot in humans) and (forming the human heel). The en d oft he Mrsometatars(ls most closely approxi mates the in humans yet is elevated s u c h that it may b e 4-25 Hvma n misidentified as the knee., giving the mistaken impre;sion tha t a bir d s point hackwarrl! The act(la/ knee is often par t I ) hid den by l ... athers. All birds lad ; m outennost fift i J toe The most common i lfrangement of the /t>ur avian toes ( digits / is sh01v n here, with one tne facing 11acJ. warrl and three facing forward. The r /Mrward-facing toe termed the h all u x corresponds t o the human big toe ( d igi t 1 1 i n the t'ingers, the of birds a r e comrosed of hones called phalanges. Each tOC! has one m ore phalan than Its positlannvm iJer, witll tht terminal phaliJn x IJearing ,1 claw. The onl y portions n( thP terminal p hal ,wges vlsih le In I hi> drilwing are the claws. F r om The Cambridge Enqodo p edia of Omilho logy, edited by Michael Brooke a n d Ttm Birkhead. t 99 t Copyright Cambridge Press, reprinted with permi;sfon. Hnrrdbook of Bird Bioloeq I

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4-26 Figure 4-22. Leg Spur of a Chickem Malesofcertainbird>, notabl y c hick e n s peafowl, and other pheasai!L relatives develop bon y o utgrowths of the lower tarsometatarsuS' known as leg spurs, which clre used as wellpons during ag gresslve interactions with rival males of the sam e s p ecies. From Lu cas and Stetten l leim ( 19 72). Howard E. Evan s and J. B. Heiser Th e tarsometatarsus represents the fusion of the second, third, and fourth m e t atarsa l s (w hi c h form lhe bones of the foot's so l e i n hu mans) with the distal tarsal bones. Thus sepa r ate tarsal (; mkle) bone s d o not ex i s t in birds, and the joint of th e ankl e is known as an intra tars a l joint. leg spurs have deve l oped as weapon s o f off e nse or defense in mal e c hi c kens and other pheasantlike bird s (Fig. 4 -22) They g row from a spu r papilla of the skin that stimulates bone d evelop m en t on th e lower cauda l s urfa ce of th e tarsometatar sus. P eafow l use th eir spurs quite aggressively, as do game cocks. All b ird s la ck theouterrnostor fifth toe(see Fig.. 4-21 ). The number of bones or phalanges in the four r ema inin g t oes i s n ea rl y cons tant eac h toe having one more pha l anx than its ordinal ( position ) number. Th u s toe numbe r o n e (co rresponding to th e innermost, "big toe" o f humans), also known as the hallux, has two phalanges, toe number two has three and soon.A numberofbfrds w ith widely different habits h a v e on l y thr ee toes, the h allux having been l ost e v o l utionari l y Th ese include s u c h flightless r u nning birds as rheas, Emus, a n d cassowaries; s horebirds such as the Lesser Golden Plove r and Sander ing ; and two tr ee-climbing birds, the Black-backed and Threet oed woodpeckers. ln add i t ion so m e birds suc h as th e diving petrels and the auks, murres, and pufiins-all n otab l e for their ability to swim underwa t e r-also h ave l ost the hallux. The Ostri c h is the sole bird with onl y two toes, as both th e outerm os t and the innermost toes h ave been lost. The Muscular Th e r e a r e three gen e ral t ypes of muscles-skeletal, smooth a n d cardiac-distingui s h ed by their fu nction s h a pe, and microscopic s tru ctu re. Skeletal Muscle Skeleta l m1,1s cle s m ove the bones and const i tute whatwecall the "meat'' of a n anima l whether it be r ed as in steak white as in c hi c k e n breast or a n y intermed i ate col o r B eca use skelet a l muscle action i s under conscious c ontrol, ske l eta l muscles are often cal l ed voluntary muscles. S kelet al muscle i s a tissue com posed of contr actile ce ll s (cells that ca n c ontra c t ) w ith nuclei n ear the cell s ur face. Skel eta l muscle cells have c haracte r is tic a l ternating d ar k and I ight striatio n s ( stripes ) atright a n g l e s to the length of the cell, which a r e v i sible und er a microscope (a fter the cells a r e put through a standard laboratory procedure that s t ains them using dyes that m ake diffe r ent s ubstances turn differe n t col ors) Th e l ong, cyl indri ca l ce l l s a r e bound toget her as muscle fibers that ca n s hort e n w h e n s timul ated b y a nerve Impulse. Once a muscl e fiber contr acts it mu s t b e forcibl y stretched to regain its resting" l e ngth ; f n other words, muscles ca nn o t push," they ca n on l y "pull." Thus muscles are ge n e rally arranged in oppos in g p airs; o n e to stretc h the --------------------Cornell Lnboratont of OrnitiJOiotJll

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a Flexor C o ntracts Pulling H o n e 8 T oward Bone A b. E.vt ensor C on trac t s Pulling Bonl' 8 Away from B o n e A other and perform the opposite act r o n on their portion of the body ( f i g 4-23). W h en muscles contract they p roduce both movement a n d heaL-actual l y more heat than work! I n effec t muscles are the furnaces of the body and the heat they produce is distributed by the blood movi ng th r o u gh the c i rculatory system. Shivering-uncoordi nat ed muscle fiber contraction Is a way to produce heat without dir ected moveme n t by muscle c ontract i o n To keep the heat generated by exerc ise or shivering from escaping t h e body, birds may fluff their feathers trappi n g a layer of insu lat i ng air. Each ske l etal muscle consists of severa l h undred to several thou s a n d m uscle fibe r s bound together by connect ive tissue ca ll ed fasci a T hese bundles of fibers have two sites of attachment to the skeleton ( and occasiona ll y to other struct ures); one is called the o r i gin, the other, r he i n s ertion Usua lly a muscle bridges one or more joinr s produ c ing movement at t h e joint when it contracts. By convention, the end of th e muscle whose po i nt of att<'lch ment moves least during contract i on Ts designated as the ori gin. The connecting fasci a may be in the form of a t endo n (which in bird l imbs may ossify ) or i n t h e fo r m of shiny, broad .sheets called apo n e uros e s Every muscle is i n nervated (supplied w i th nerves) and ke p t a l ive by these nerves. I f the nerve to a mus cle is cut, the muscle will eve n tua ll y shrivel and atr ophy ( dfe ) unless new nerv e f i bers g row into it, a process that usua l l y t akes several weeks Skel etal muscles are often given names that indicate their fun c tion locat i on, shape or derivation. Most anatomical terms were fi rst created to des c ribe human anatomy, then un c r i tica l l y to birds at a la ter da t e. Thus, man y inappropriate names for bird muscles haw had to be changed to more p roperly reflect the i r evo l utionary origin and av i an f uncti o n (see Baume l eta I. 119931-the Handbook of Avian Anatomy--listed with refere n ces). H andbook of Brrd Bioloat t 4-27 Figure 4-23 How Muscles Actl o M ove B o d y Parts: Skeletal muscles duough t herr attachment s to hones, c1re (or moving the body parts. Musde>, howe ver, can o nl y pull-they cannot push-soskeletal are .lr ranged in pairs. one opposing the pullin g action of the other, to produce smooth oi the l>on.:s. Each mu scle usually bridges o n e or more joints IJetween bones moving the joint when it contracts Each mu scle has two points of ,Jftacllme/11 t othe$ke leton, its origin and I t s i nserti o n n11! origin fs defined .1s the e nd oitlw muscle whose point oi, JIIadlme/11 moves the least during the muscle's c ontractio n M u scles are termed flexors or ext e nsors depending on the aclfons they exer t on the body parts. T hi s figure shows thP actions of two IJypothetical /Jones and muscles a Flexor Contract s : I Bone B is pulled toward Bone A ( a movemont termed lle;
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4-28 Howard E. Ev"ns and J B. Heiser Skel etal mi,Jscles t hat move t he wings and limbs ( Figs. 4-2 4 and 4-25) act antagonistically so th a t when one contracts, the other relaxes in a conti nuou s fashion, producing smooth rather than jerky movement. (Handy examples are the muscles of our upper arm. When we raise a cup to our lips, we bend (f l ex or close) the elbow joint by contracting the biceps muscle that crosses the inner or flexor surface of the elbow. In the process the antagonistic triceps muscle---which crosses the outer or extensor surface of the elbow joint-gradually rel axes, allowing the arm's extensio n to be contin uous and smooth The reverse is true as well. When we lower the cup a nd open the elbow joint, the triceps muscle con tra cts, w hil e the biceps relaxes. ) The large breast muscles of birds the pectora l is a nd supracoracoideus, are good examp les of antagonistic muscles (see Fig. 5-6) Al though they I ie in similar positions on the keel of the sternum the y hav e different actions. Thi s is because the tendon of the $ Upracoracoideu s passes through the fo ram e n triosseum ( "foramen" means ho l e ")1 an opening at the shoulder insertion formin g a pulley system that redirects the force of t h e supracoracoideus. The pectoralis attaches to the ventral s urfa ce of the humerus and draws it and the wing downward. The tendon of the supracoraco ideus passes through the foramen trios seurn and inserts on the dorsal surface of the humerus so it c an ((lise ( e l evate) the wing. Thus the two primary oppos in g muscles fo r flight the pectoralis for the downstroke and the supracoracoideus for the upstroke both originate on the sternum one on top of the other. Even in the chicken and turkey not known for their flying prowess, the pectora l muscles account for about one fifth of the bird's weight. Because of the pulley function of the forame n triosseum the large flight-powering muscle mass can be car ri ed entirely below the supporting wings during flight-a con siderably more stable weight configuration than if the wing elevator muscle were situated on the back above the wings. Because it takes the most force to get lift (and thrust ) from the wing' s downstroke, the pectoralis muscle is the larg est muscl e in f l ying birds. I t is placed s uperfi c iall y thus its bulging during contraction is not hampe r ed b y overlying muscle. For more 1 nformat1on on the fl1ght muscles of birds, see Ch. 5, Functions of the F l ight Muscles. Refer to Fig ure 4-26 for more information on the major skeleta l muscles of birds. Smooth Muscle S m ooth muscle a lso known as involuntary muscle because it is not controlled consc i ously i s composed of spindle-shaped cells with a centrally located nucleus and no evi d e nt pattern of striations a long the cell. Smooth muscles are found in th e walls of hollow organs such as the stomach and blood vessel s larger than capil l a r ies. Smootn muscle cells are especially c haracteristic of the vessels of the arteria l system but a lso are found in the venou s system. Smooth muscles are innerv a ted by a separate, non-voluntar y ( autonomic) portion of the nervous system and also are under direct c h emical control from Cornelll.nboratollf of

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Chapter 4 -What's Inside: Anatomtl and Extensor Metacarpi !Extends Hand / Biceps Brachii (flexes Forearm/ Semitendinosu s Flexor ( Pulls Thigh Backvvard) -Gastrocnemius (El origimtle; abovli! the e/b<;,w, insens on the carpo m etaC.1f[IIIS hy a long tendon and extends the h.1nd. IL< antagonist, the flexor dlgi l !rllm superf1dalis Otlginales below the elbow, inserts on the carpomelac:.Jrpus, ilnd flexes /he h,llld D!CJwin81Jy Charles l. Ripper Figure 4-25. Selected Muscles of the Avian Leg: Shown h e r e are some o{ the I ) ire/'s les nwscles and their arrangements lor moving the lees Jnd leer. a. Muscle s and Tendons in Natural Position: Tht" il iolibialis e x ten so r origina ting from t/11{1 pelvic girdle inserts ill the k11ee wh!' r e illilis the th igh (mm the midline of th e hody
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4.3 0 Depressor Cauda e Fig ure 4-26. Selec t e d Mu scles of the Rock Dove: This drJwing shows many of the superficial muscles o(ih erighl side in lateral view. Notice the co mplex network o i s m all muscles along the neck, the multifid is c ervicis each s urrou ndin!J and con trolling a cervica l vertebra all(/ thqscontributing tu the neck's ne.)(ibility L ong muscles, the semispinalis anrllh e l o n g u s co IIi move the neck up a nd /;>ack, a nd down and forward respectfve/ )1. In t1ying birds, suc h ,Js tllis Rock Dove, the p ec torali s and the underlyin g s upra coracoide u s muscles, which provide the po,. r e r for flapping the. Wings, m a k e up b et>Veen :w a nd JO percen t o i the body weight ,1nd thei r importilnce cm1 clearly be seen her e The muscles of the for instance the ser
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Chapter 4What's Inside: Arratomtt arrd PhtjsioloBtt substances circul ating in the blood. Smooth muscle is also found in the respir<'!tory and urogenital systems, i n add i tion to th e digestive and cir culatory systems already mentioned-all systems and organs that are concerned with vital l i feprocesses andover which the bird has littl e or n o control. Smooth muscle occurs in the skin for the movement of feathers in birds and for the movement of hair i n huma ns-sometimes causing "goose flesh ." Smooth muscle i s also essential in the eye for changi ng focus. Cardiac Muscle C ard i a c mus cl e is a special type of smooth muscle that forms the bulk of the h eart. The muscle are a rr anged i n a fused network and have cross-str i ations but cent r a lly located nu clei. Card i ac muscl e has an inna t e rh ythmic ity-theability to contract without being stimu l ated by n erves. Actually, the heart o f an embryo begins to beat rhythmically before any n erves hav e grown to r each it. The nerves that do reach the heart are part of th e autonomrc nervous system (see l ate r in this chapter), but the y do not start the contractions oi the heart. Instead they r egulate and modify the rate of the beat. The Nervous The nervous system is responsib l e for all the bird sees, hears smells tastes, feels, thinks and does. Thus the nervous system transmits sen s ory stimuli, evokes appropriate motor responses, and regul ates a ll internal body functions. Th e structural parts of the nervous sys tem are similar in all vertebrates but they differ in their degree of complexity.. Mammals have th e most complex brains of all verteb r ates, wherea s the av i an brain ha s tradition ally been conside r ed less compl ex. Calling so m eone a "birdbrain" is generally not intended to b e compl imentary! However, rather than be i ng les s compl ex overall the bird's brain is differently organized than t hat of a mamma l. In othe r words the brain of birds is composed of t h e same basic "component s" as that of m ammals-due to inh eritance of the basic structure from our common ancestor-bu t the avian bra i n is ''wir ed'' d i fferently. To appreciate how any an i mal perce ives the outside world, we must conside r its simp l e sensory nerve endings and complex sense organs which are constant l y gat h e r i n g and transmitting information about internal and external conditi ons. Birds have some sensory capabilities for species re cog n i tion and orientation, especially in migration a n d homi ng, which we do not yet fully und erstand (see Ch, 5, Orientatio n and Naviga t ion). These include the bird s a b i lit y to see u l traviolet light and the probab ility that t hey ca n hear in frasound and u l trasound. The c e n t r a l n e rv o u s syst e m consists of the brai n and s p i n a l cord The p eriphe r a l nervous syst e m consists ofbundles of n erve cell fibers, called n erves and co l l ections of n erve cell bodies c l ustered in aggre gations called ga n glia The c r a nial and spina l nerv e s serve various very specific parts of the bod y Th e auto n o mic n e r vous syst e m con s ists ot Handbook of Bird BioloBq 4

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4 Figure 4-17. Neuro n Stru c t ure : Tl1e n e u ro n or nerve cell is the basic: com ponent of tlu< nervous system. The two fundamental t ypes o( neurons sensor)' and motor. differ in lheir fun c tions, bill have the same basic structure, Ench consists o( a cell bo d y many rootlet like evtensions called dendrites and,, very long, n1ble-like e:.:tension the axo n which is surrounded a long Its emire l enf?lh b y a fatty, insul' Charles L. Ripper. Myelin Sheath Nerve Impuls e j (rom Spinal Cord .1nd Brain Motor Neuron Howard E. Evarts andJ B Heiser Nerve Impulse to Spinal Cord and Brain Myelin sheath Muscle Sensory Neuron those nerves that r eg ul ate t h e smooth muscle of the viscera g l ands a n d blood vessels. One cannot tell the difference betwee n cra nial spi nal, and autonomic n erves b y a n y mean s other than t h eir origi n desti n ation, and fun ction Physi cally, a ll nerves took a l i ke. The Neuron The basic uni t of t h e ne rv ous system i s the n euro n or n e rve cell ( Fig.4-27). W h a t we ca l l a n e r v e i s a collect i on of specialized portions of many nerve ce l ls, s urrounded and bound toget h er by connective tissue (ce lls that gtve suppor t and prot ection) and large e n OL!g h to b e seen by the n aked eye. The s i mple s t n eu rons have a cell body with l o n g, rootlet -like exte n sions (ca lled d endrites) at one end, a nd a cable-l ik e exte n sion (called th e ax on ) issuing from the o ther end. Bioelectric impulses l n erve impulses ) travel a long n e urons from one end to the o th e r A bioelect ric impulse con sists o i a wave of c h a n ge in e lectri cal c h a r ge sweeping along the s urfac e of the n euron due to i o n move" men t across the ce ll m emb r a ne. Tran smiss i on of an impulse from one neuron to another takes place ac r oss a s m all gap, o r syn a p s e u sual l y fro m the axon of p ne n euro n to o n e of the dendrites of ano ther T h e cell body o f a n eu r on is microscopic i n size. yet its axon, a l so mic ro II L.ahoraton1 of Ornitholo&11

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C l1apter 4Whats Inside: Anal'omtf and PhtjsioloB\1 scopic fn diameter, may be seve r al feet in length. A w r app ing of ce ll s contain i ng fatty mater ial called myelin surr ounds many axons. These mye l i n sheaths function in part, like the insu l a tion around househo l d wiring. Because the fatty coats appear pa l e o r white, nerves s t and out visually from mos t oth er t issues. T he deposi tion of myelin ( m yelina tion ) in the nerve sheath is im porta n t i n the functio ni ng of the nerve iibers. I n hu mans, myelination beg ins in the emb r yo, generally i n t h e mor e primi tive nerve pat hs, reach in g the more advanced paths after birth. For examp le, mye l i n a tion of the most importan t motor pat hway-the nerves that govern walking-begins after birth and proceeds most rap idly between t h e ages of 1 2 a n d 1 6 months. T h e h uman infan t beg ins wal king w h en myel i na t ion of tha t motor path way develops to a certai n point, a n d not before; so a c hild cannot be taught or forced to walk u n til h is nerves and muscles are capab le. We assume the process is sim i l ar in b irds. The parent b ird never "teaches" the n estl i ng to f ly, The youn g b ird flaps its wings, stretches its legs1 stands f n t he nest, and illes only w h en t h e nerves and muscles have developed to a ce rtai n point. After mye l i n ation of t h e nerves govern ing f light is co m p l ete, not h i n g, except conii ne m e n t or in j u r y wil l keep t he bir d from flying. S en sory and M o tor N euro n s Two types of neu r o n s a r e d i s tingu ished not on t h e basis o f struc tural differences, but on the function and direc t ion of the impu lses they carry (see Fig. 4-27). A sen so r y n e uron con veys impu lses t o the spinal cord and b r ain. T hese impulses are i nterpreted as sen sations, whi ch may be conscious-such as visua l images of food i tems, so u nds of a pred ator, or pai n from a n injured wlng-or t h ey may be subconscious i m pu lses from muscles, tendo ns, and j o i nts informi n g control centers of the position of t he limbs and musc les. This g i ves the bird a ''body parts-posit i o n sense," and allows it t o s t and o n one leg o r fly without vis u a l cues. These l atter i m p ulses are called proprioceptiv e mean i ng muscle sense" o r tendo n sense." Position sense is very importa n t for proper fun ctioni n g of skeleta I muscles. Because of the propr iocept i ve neu r ons, yo u can move you r a rms and legs with your eyes closed a n d sti l l k now the i r exact position. I magi n e how i m portant these neurons and the knowl e d ge t hey p rovide must be to a b ird flying at night, or to spec ies that l ive deep i n caves. M otor n euro n s convey impulses from the b r ain and spina l cord to s t imulate a muscle to con tract o r pe rmit it to rei a><, o r to cause 3 g l and to secrete. For examp l e u pon seeing a banana split, most of u s iee l a sensation of delight resu lting from sensory neu r ons sending an image message t o the brai n The bra i n will l i kely se n d a command by motor n eurons to t h e salivary g l a nds, mak i ng o u r mouth wate r even befo r e t h e first bite. The motor ne r ves stimula ting skeleta l muscles are ca ll ed vo lun tary m otor nerves because t h ey are under consdous contro i T h ey a r e of v i tal importance t o the well -bei n g of the muscle If a motor nerve to a ske l etal m uscle is cut or dies of polio virus the m u scle is paralyzed of Bird Bioi oM 4

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4 Figure 4-28: A Simple R eflex: A nerve impulse fr o m the skin Is c arried b y il sen sory neuron to the spinal cord There it transmitted ac;mss a s y napse between the sensory dendrit e s and rhe dendrites of a motor n e uron through w/Jic!J il trav els t o a musde where it s t i mulates in s lant avtomati c a c tion. An example of a s impl e i s t/1e un conscious way we pull our hand a w a y from a hoi surface; our an' n mu scles-conttact auromati c all y to wirhrlr R w ou r l1and before our brain tells us the wrfac e I s hot. 0Tawing b y C h arles L Ripper. Howard E. Evans andJ B. Heiser and no longer can be moved voluntarily With the passage of time, such denervated muscle waste s away and its fibers degenerate unles!> they are kept alive by r egrowth of nerve or art ifi cial I stimu lation. D estr u ction of nerves within the brain andspina.l cord is usually permanent; ove ral t littl e or no regeneration o c curs a l though some clusters of neurons deep in the brain show some small regeneration potential. If an axon outside the brain and spi nal c ord i s severed, however, it wi II regenerate The growth is slow about 0.04 i nches (one mtllimeler) per day in humans. The length of time between the loss of innervation and the re.estab l ishment of nerve cont act determines whether the muscle will function again. A wild bird is so dependent on f l ight that it will die from an accidentall y denervated win g before any significant regeneration of nerves can occur. The e xistence of sensory and motor neurons provides a basis fo r the simplest kinds of behavioral act i ons, call ed reflexes ( Fig. 4-28), which may be either automatic or l earned. Sensory neurons carry im pulses from a ll parts of the body to the central nervous system. There, neural activity is transferred by synapse to a motor neuron that stimu lates instant a c tion (the refl ex ) in the muscle or g land it governs. One example is the speed with which we withdraw our hand from a hot stove; the arm muscles automatically contrac t to withd raw t h e hand before our brain tells u s th e stove is hot. Identical a utomatic reflexes protect the b1rd from injury; l earned reflexes prov i de greater scope for other, more compl e x act ivities. For example, flying is d ifficult for a young bird just out of the nest ; it has trouble taking off and l anding properly Graduall y with continued practice, the many mus cular con-Spina/C ord tractions necessary for flight are coordinated Then the bird can turn its attention to other th ings-to catching food watching fo r predators and even to navigating," a complex process tha t we still do not fully und e rst a nd Reflexes are usually muc h more complex than we have described because the motor and sensory neurons involved have interneurons within the spinal cord interposed between them (Fig. 4-29). Inter neurons allow for transfers up and down the cord to other regio n s as well as between the l eft and right sides of the body. Furth e rm ore the Com e ll Lnboraton1 of Omid'IOIOBLf

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Spi n a / Cord lntem e uron s Sensory Neuron neurons i nvolved in reflexes connect in the spi nal cord with additional neurons that carry sensations up to the brain. They also synap s e with still other neu r ons t hat bring impulses directly from the brain. Brain input often modifies a r eflex action. For example when a professiona l chef grabs a hot pan h e may not re lease it instantly r n a ref l ex action as most people woul d. I nstead his bra i n may te ll him to hol d on even thou gh it is hot, be c ause it is important to the success of h is job. "Wirlng diagrams of the nervous system from its i n puts to its outputs thus become exceedingl y complex, even at the s e rel atively simple reflex levels of n eural i ntegration and behavior. I magine what occurs in the nervous system of a Clark's Nutc racker as it recal l s th e location of a pine nut stashed months earlier and then flies directly to the site and retrieves It! ( See F igs. 6 12 and 6 13.) Central N ervous The central nervou s s y s tem ( CNS ) consists of t h e brain and the spinal cord Both are composed of millions of neurons receiving sen sory information relaying it to many other CNS centers and sending out motor impulses. Within the CNS c l usters of nerve ce l l bodies ( equlvalent to the ganglia of the periphera l nervous system lPNS]) are ca l led nuclei, a n d b u ndles of axons and t heir myeli n sheaths ( equiv alent to PNS nerves ) are called trac t s (fig. 4-30). The many adja c e n t tracts within the CNS are known as "white matte r because of t h e color of Bird BioloBlf 4 Figu re 4-29: A Compl ex R eflex: A nl!!fv'(l impulse fr o m th e skin i s carried by a se n sory n euro n into t h e spina l cord. Tlmwg h S)'llilpses w ith inle rn e uron s Wilhin Ill& spinal cord, 1l1e impuls e m ay b e tran smitte d fr o m o n e sideofth e b o d y to th e o ther, up .1nd do w n l h P corrl o r 10 and fro m th e bra i n lnt E rpt e tiv e input iro m th e ce ntrn/ nervou s syst e m k H ins t a nc e i n the i o rm o f e x p e rien ce and m e m o ry, miJy modif) th e r e fle1< ac t ion Drawin g b y C h arles L. R i pper.

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4-36 Figu r e 4-30. Organ i zation of /he Vertebrate Nervou s System: The brain and spinal cord together are termed the c entral nervous system (CNS). Tile peripher.1/ nervou s system !PNS) con-sis.ts of afl other nervous system struclures--the cranial and spinal nerves and their associated ganglia. \ 1\fithinthe CNS, the axons (fibers ) o( neurons are gathered into tracts clusters of neuron cell hodies are termed nuclei The col/ertive name li;lr CNS is "white maller. from the white color of' /he axons' myelin sheaths. The colleclfve 'lilme (or CNS nuclei is "gray matter. tram tl1e darker co lor of cell bodies. Within the PNS, the terminology is differenr Neuronal axons are gat l wrcd into nerves bundles surrounded !J>' a prorective connective I issue thM ,1re oftel) large e nough 1 0 visible lo (he n.1ked eye. Neuron cefl bodies arf coll ected inw rounded ageregations c.11/ed ganglia (sinsulirr, g.,ng/ionJ, Howard E. Eva1'1S and J. B. Heiser CENTRAL NERVOUS SYSTEM PERIPHERAL NERVOUS SYSTEM tflr.1in and .Spin.11 CufU/ lA/I Ot/wr Norvuus System Structtm:sl Neuron s form Tracts Neuron A xons fonn Nerves Tracts collectively form Wlrite Matter Ne uron Cell Bodies form Nuclei N euro n Cell Bodies form Ganglia Nuclei colleclive l y form Gray Maller of the myelin sheaths. Areas without mye l in where n erve cell bodies are concentrated are darker and called "gray matter." In addition m il lions of non n eura l ce lls (neuroglia ) fo r m a s upporting and p r otect ive fe lt-like bed for the neurons. Surrounding the bratn and spina l cord are vascularized membranes cal l ed meninges. T hey consist of an outer fibrous dura and inner arachnoid and pia layers, tight l y applied to the surface of the bra i n and cord (see Fig. 4-33). This complex of non ne u ral tissues provide s u stenance and waste removal for th e cells of the brain and spin al cord-vital f un ct i ons because no blood vessels p e netrate these organs to pe r form those duties. At the same time the meninges estab lish a blood / brain barrier that p r otects the de l icate CNS f rom many pote ntiall y toxic substances c i rculating in the body. Brain Th e bra i n of a bird i s short, bulbous, and very l arge in relation to the size of the skull (fig. 4-31). Most of th e brain lies caudal to the orbits and it f ill s the cra nial cavity completely. The skull isthin and the neck vertebrae exceptionally f l ex ib le, ther efore the brain and ce rvi cal spi n a l cord ca n be Injured easily, as illus t rat ed by the number of birds that die after f l ying h ead l ong into windows. The main features of the bird brain are sim i la r to those of the mammal brain: the two large smooth cerebra l hemispheres of the forebrain ; the two larg e optic lobes of t h e midbrain; a n d a. s i ngle large, median cerebellum of the hindbrain with lypica l transve rse folds. Between the forebrain and tht:! midbrain is a r egion thatserve.s ilS the brai n's ce ntral switchboard for all incomi ng and outgoing nerve impulses.Theventral portion, the h y p o thalamu s (wh i c h con tain s the pituitary g land ) plays a major role in the hormonal control of body processes (th e endocrine system ) The forebrain, spec i fically the forwardmost portion known as the telen ce ph alon, primitively associ ated with the sense of smell (ol fact i on), i s narrow rostrally and wide ca udall y w h ere iloverlaps and partially hide s the more caudally positioned optic lobes. The for eb rain of modern bTrds consists of two smooth cerebra l h em i spheres, pointed at ro s tral ends where the olfactory nerves from the nasal cavity en ter. The cerebra l hemispheres are coordinating and contro l centers for most of the bird's complex behaviors including memories and learn ing. Of a II birds, th e l a r gest olfactory a rea is that of kiwis-primitive, Cornell Lnborator14 of' OrnitholoBI1

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Chapter 4 What's Inside: AnatOITuf and Phttsiolo9'1 a. Location of the Br.1in Within the Skull b. Structure of the Brain / ,.' XII Spi nal Cord X &XI 4 Rock Dove Cerebral Hemi;,phere Rock Dove Lobe -..,-II Optic TrJct ( Optic Norve } Gland \1 I T/Jrough XII= Cr.:tnial Nerve Endings Fi gure 4-31. Location an d E:dernal Structure of th e Br ain: a. Location of the Brain Within the Skull : The hird'sbrain is posi tiotwd tow ard the rear of the skull, behind tlw large eye sockets. Theorienti'ltionotthebrait1 in the skull varies considerahly, but in tnilny species it is oriented nearly vert/CiJII)t, as i t J the Rock Dove shvwn here, in c untr:rst tv the classic mamnMiian orienl i rtion in whic h t he brain lies lwriznnttJI!y. b. Structure of the Brain: The Dove brain is shown here in lateralvie"'t. Dominating the forebrain are the l arge smoo th cerebral hemispheres which coo rdinate and con trol co mpl e x behavio rs. At the anterior end of the {Jemisph eres art' the small olf.Jctory lobes, concerned with thesenseofsme/1. The midbrain is dominated by the large poi red optic lobes which receive the optic tr,1cts from th e eyes. Upon exi tin g the eyes. t i Jeoptic tracts partially cross each other within the optic chiasma ( n ot visible ) before entering the optic lnhes. Thus part of what/he right eye sees goes ro rhe left side of tiJe brain and \ l ice versa. The pituitary g land Is a tl lChed to the ventral side ofthebmin by a st11lk, IVhich not visible here, On rhe dorsal surface 01/he llinc/IJrain is t h e ldrge deeply told ed cerebellum which controls muscular courdinil t fon .ttld has importanr roles in posture illld proprioceprion rthe seMe of the position ,md ,lctivity of the 1/miJsl. Ventral tu the cerebellum Is I hi" medul/.1 oblong a ta, wherli' the nudd of most of the cranial nerves are l oca ted, ilndti-om which thest' nen 1es ex t end out to the head nt:!Ck1 ,mel tlwrax The crania/nerves are numlmred I rhroit gh XII; onlyth eit ends are illustrated. n1e medulla oblon gata r a /so cal l ed thiS' bra in SIIE'm) ex tends Ciludafl)l to become the spinal cord. Modified from Manua l uf Ornithology b y NobleS. Proctor and PJttick } L y tlch, with pemdsst'on of the publisher. <..opyright /993 \al e University Press. Handbook of Bird Biolo[ilf

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4 Lateral View, Right Side Reptil e Bird Mamnml B Ce>rebra/1-/eml.te>ba l/um l!i!il Opticlobe ( bare/)' visiiJ/e in f11,1mmc11J Olfactory Bulb Howard E. Evans and J B. Heiser ilightless birds of New Zealand. They are th e o nl y t h<1t have their nostrils atthetip of the b ea k rat her than n eare r th e baseofthe beak. Th is posifio1i facilitates efficient o l f ac ti on, as th ey feed b y probing into the forest leaf I i tter. The tubenosed seabi rd s and some New World vultures a l so h ave specia l nasal passages and/or re l ative l y l arge o l factory areas and excellent senses of sme l l. Most b i rds, howeve r appea r t o h a v e few olfacto 1 y talents d epend ing muc h more on vision. The bird1s midbrain or mesen cepha l o n i s the r egion where visua l mputs are regulated and sent to o th er parts of the brain for integration into a respo nse lo w h at has been seen It cons ist s primarily of two greatly e nl arge d optic lobes, which receive t h e optic tracts from the eyes. These connedions between the eyes and the brain are call e d tracts rather than nerves because th ey ( and the sen siti ve layers of the eyes) are outg1 owths and modified exte n sions of the brain r at h er than bundles of peripheral sensory axons. Exiting the eyes, the tracts cross each other berore ente rin g the brain. Thus, what the r ight eye sees goes to the l efts ideofthe brain and vice versa as in humans. The l arge optic lobes of birds are relatively much l arger than their corresponding pati in mammals (fig. 4-3 2 ) On the oth e r h and, the auditory ( h ear in g) and vestibular (ba l ance) compone n t s of the avian midbrain a r e not as consp i cuous as they are in m amma ls At its cauda l end, the m esen cep hal on is joi ned tu the cerebell um. The ce r e b ellum is attached to the dorsal side of the brain ste m ( m edulla oblongata ) by two pairs of stout n eural tracts Th e cerebellum con trol s posture and the moveme nts o f the legs and wings; it thus r eg ulates the h igh l y comp l ex muscular actions necessary for ilight. The I Jird s ce r ebellum is large relative to o t her porti ons or the brain, when rompared to mammals doubtless b ecause o f the demands of flight. Much of the m edulla oblongata is hidden from dorsal view by the l arge cerebellum. The medulla extends cauda ll y thr oug h the forame n mag num, the l arge open in g a t the rear of the s kull where the medu ll a bends sharply and n arrows to become th e spinal cord.lmportantne r vcs h ave thei r nuclei ( reca II that t hese are aggrega tions ofcell bodies) w i thin the medulla and extend from it ou t to the h ead, n eck, an d t h o rax Spina l Cord The spina l cord passes t hrou g h the n eck and trunk in t h e pro tective, but in some region& hi ghly fleJ part>ofthe !>rain 'hilded identically in each. D ifferences in the proportions of vari o u s !)rain parts rellect !he Vdr)'in!J ahllities, needs, and habits ul' !he different vertebrate groups ForexampiP the optic loheso(birds Jre 'f'/,1/lve/y much larger !han those of mammals whose optit lobes are obscured by the large complex cerebral hemispheres. This shows the importanet ofslg/1110 i>lrtls, The hird:' cerebellum is (!/so relative/)' farge co mpared to that of mammals, rellccling tflt imponance ofblllance cluriny fiiRhl. Note the r elative differcrJC('S in the si:t.esoft heolfactur y lobes: while small in birds the y me welldt!vl'ioped in fish, reptilos, ancl mammals, e\ ,idenc:e /,J/tCr three have a sense of smell superior to that of!Jirds. 1\rlnptm fmm Poug/1. janis. Jnd 1-/ciser ( 199'1, p. 1 01 l Ccmell La bora of' OmitholoB'I

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F11sed Thoracic Vertebrae Ventral Root in volved i n flyin g and wa l k in g. B eca use of t h is 1 n de p e nd e nt spTn al cord f uncti on, w h e n a bird is decapita t ed, it s legs a n d wings con tinue t o func1'ion for a b rief period ( t h e prover bia l runn i ng aro un d l i k e a chicken with its head cut off") Along its course, the s pinal cord gives off s p i n a l n erves b e t ween t h e vertebrae Each spi nal n erve has sepa r ate sen sory a n d motor seg me nts that exit f rom the cor d b u t they a r e com bi n ed i nto one spi n a l n erve outside the vertebra l ca n al. A t both t h e l eve l of th e w ings and t h e h i n d limbs t he sp i n a l nerves a r e l<}r ge a n d j o in eac h otherto for m com p l ex webor ne t-lik e struct u res calle d ple x u ses out s i de t h e ver teb r al cana l (Fig. 4-3 4 ) The brachial plexus of t h e win g i s associated with a cervica l enla r ge m en t of the sp in a l cord w i thin t h e ve r tebra l ca n al. The lumbos a cral ple x u s of t h e h ind l imb l ikewise co r respo n ds to a l umbosacra l enlarge m e n t of th e s pinal cord. W h e th er o n e o f t hese sp i nal cor d swelli n gs is the sam e s i ze or l a r ger than the o th e r depe n ds on a bi rd s ma in typ e of locomotion. In a b i r d t h a t r elies o n wa l k i n g, such as a k iwi, the num ber a n d s i ze of th e nerves go in g to a n d from t h e legs i s ce rt a i n to be large, as are the lum bosacra l e nl a r ge m e nt s of the spina l co r d. I n a bir d tha t seldom wa lks, s u c h as a n a lbatross, the cervical enlargeme nt of the spina l co rd a n d t h e n erves going t o the w i ngs a r e larger A featur e uni q u e to birds is a n rhomboid sinus-on the d orsa l m i d l i n e of t h e l u m bosacra l e n l a r ge m ent, w h i c h contains a gelatinous mass of sup po rti ng n eurogl i a l ce lls. T h e mass i s ri c h i n t h e nu tr i t ive s u gar glycoge n a n d t hu s i s know n as t h e g lyco gen body The f un c tfo n of thi s structure i s still unk nown P erha p s i t is a n e n ergy r eserve th at susta in s the reflex activity n ecessary for r oos tin g o r other chronic l eg posturing, such as du r i n g long flig hts. H a ndbook o f B ird Biolo&' f 4-39 Figure 4-33 The Spinal Cord in Re l ation t o t h e V e r tebrae: The spinal cord lies within the protectiv e confines of the vertebral c:an,1/, a bony tube formed II)' the interconnecti JB vertebrae. This drawing shows the sed ion of s pinal cord IVi (hin par/ o( the thoracic r eeion Of fha vertebral co lumn. Surrounding t i l e spiMI cord are rhe merringe wJscularized that nourish the nervous /issue. They consist ol a fibrous <>Iller lu)ler, the d ura, and rw o inner layers, the a rachnoid and pia. The spi nal co r d itself c .1n be seen in c;rosssection show ing the while miJIIer made up of nerve axon>, and the gra y mat ter, made up(){ n erve cell bodies At regular intervals ,,long its /eng/11, the spinal cord gives off bundles of sensory and motor neuron; thllt exit from the cord in pairs betwe e n the ver tebrae; these are termed the dorsal and I entral nerve rooLS, respectively. These bundles o ccur symmetrically on both the left anrl right sides oft h e spinal cord. The members of each dorsal -ventrtJI pair uf roots immediately co mbine to form a single s pinal n erv e which Innervates nearby m uscles or organs. Associated with the spina/nerves is a c hain of sympathetic ganglia running parallel ro the spinal cord on each side, These ganglia contain the cell bodies of sympathetic neurnns, [Mrt of the autonomic nervou s system (see Fig. 4-35). Adap t ed from Proctor a n d L ynch (199 1 p. 241)

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4 F i gure 4-34. The Spi nal Cor d Showing Nerve Plexuses: At t wo locations ;rlong the $pinal cord, spinal nerves exirin !f the cord are par/icul.1rly l,,ge and joined into co mpleA webor net-like su uctuh% called plexuses. The bra chial plexus is fourcf i!t the level of the wi ngs, and is associated with a swe ll ing of The spinal cord calle
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Chapter 4-What's Inside: Ana and Ph11slolo9'1 II. Optic Nerve This large "nerve'' of vision is actually a sensory tract from the gan glion cells of the eye's ret1na, rather than a standard nerve. The opt ic, nevertheless, is by tradition enumerated as one oft he c r ania l "nerves." All visual sensations from the millions of closely packed visual cells in the retina of a bird are transmitted to the brain over these robust cables. Each optic tract enters via its own optic foramen into the skull. It then crosses to the opposi reside of the brain atthe optic chiasma and enters the brain. The optic tracts are larger than any other c ranial "nerve." As would be expected, the optic nerve is particularly large in visua l predators such as hawks, and small in many nocturnal birds Ill. Oculomotor Nerve This motor nerve moves the eye by co n tr olling contractions. of some of the muscles that run f r om the bony orbit to the surfa c e of the eyeball.ltalsosupplies the eyelid muscles and the tear gland of the ni c titating membrane. The nerve originates in the midbrain and branches to its target structures after exiting the skull. IV Trochlear Nerve This small motor nerve c ontrols just one eye muscle not inner vated by the oculomotor nerve. It originates on the dorsal surface of the brain stem, and exits through its own foramen in the skull. V. Trigemina l Nerve This second largest cranial nerve has both sensory and motor co mponents. It divides into ophthalmic, maxillary, and mandibular nerves after exiting from the brain thus its name, which means triplet. The ophthalmic nerve is sensory from the nasa I cavity (fo r nono l factory nasal sensations), eyeball (for nonvisual eye sensations), upper eyelid forehead and upper beak. It is very important to ducks and geese, in which i t innervates the specialized bill tip organ: a concentration of touch or mechanoreceptors with which the bird seek s submerged aquatic vegetat ion by feel. The maxillary nerv e is sensory from the skin of the face, upper jaw upper eyelid, and conjunctiva (eye covering tissue). The mandibular nerve is sensory from the lower beak and cor ner oft he mou th, and motor to the muscles of lower beak movement which correspond to the chew i ng muscles of mammals. VI. Abducent Nerve This motor ner v e stimu lates the one r e maining muscle of the eyeball and the two skeletal muscles that pu ll the nict it ating membrane across the eyeba II. V II. Facial Nerve This moto r nerve stimulates the muscles for protruding the tongue (muscles attached t o or assoc iated with the hyoid skeleton), the de pressor muscle that l owers the lower beak the c onstrictors of the neck and the muscle that tenses the col u mella ear bone (see Fig. 4-48) I t a lso may carry some taste fibers from the tongue. Handboak of Bird 4.41

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4 42 Howard E. Evai'IS andJ B. V III V estjbulococh lear Nerve Formerly calleci the a u ditory, acous t ic, or statoacousti c nerve, thi s is the sensor y nerve for balance a n d hearing, as the L atin n ame implies. I f is composed of two parts: t h e vestibular part for balance a nd the coc hle ar part for hearing. The vestfbul a r part Tnnervates the region of the inner ear that detects the directi o n of g ravit y as well as acce l e r atio n s in three-di mensi onal space. The coch l ear part contai n s axons co rnin g from a distinctly different region of the inner ear r e s ponsible fo r t h e sensation of sou nd (see Fig. 4-50) No part of this n erve ever leaves t h e skul l. IX. G lossoph ary ngeal Nerve This sensory and motor nerve innervates the tongue, pharynx esophagus, and thr oat. I t also carries fibers from a specialized gan g lion O l i t h eir way to cert-ain b l ood vessels, and motor fibers to the salivary g lands of t h e tongue ><.Vagus Nerve This is the m lljnr viscera l sensory and motor nerve to the ab. dom1nal orga n s It arises from the medulla by a series of segment s in close associatio n with the glossop h aryngeal and accessol'y nerves, with which it exchanges fibers. After leavi n g the s kull, the vagu s sends fibers to the pha r y n x and larynx befo r e passin g down the neck o n the s urface of the jugular vein. Within the t h orax it branches to the heart and lungs before sendin g branches t o the gizzard, liver, a nd i ntestine. XI. Accessory Ne rve Thi s n erve is of v isceral m otor function and i s distributed in the head r egion with the vagus to inn e rvate the cons tri c tor muscles of the n eck. n exit s from the skull with the vagus. of Its exit site and iunct ion i t i s i ncluded i n the "cr a ni a l '' nerves, bu t i t has a very circuito u s origin w ithin t h e upp e r neck that is tho u ght t o reflect an anc i e nt evolut i o nary "ca pture of a spin a l n erve for "crania l n erve funct ions ." X II. Hypog lossal Nerve The h ypoglossal n erve joins wilh crani a l nerves I X and X to f orm a co mbin e dtrunk that con tro l s moveme nt of the tongue, larynx trachea l muscles, and syringeal (of t h e syrinx) muscles. The tongue in most birds Is much less muscular and mobile than that of mammals, a n d thus requires less hypoglossal con trol. Parrots, however have highly manipulative tongues, and thus the brain stem nucle i for t hi s portion of a pa rror's h ypoglossa l n erve a r e large i n s ize. T h e syri n x is uniqu e to birds, and in t hose that have comp lex songr the hypoglossa I b r anch that s upplies I t fs of major importa nce (see Syrinx, l ater in this c hapter). S pinal Nerves Spinal nerves are paired in a ll cases-on e on each s id e of, a nd a l tac hed to the spina l cor d. They a r e sensory a nd moto r to a very specific (and usu a l l y closely adj acent) r egion of skin muscles, and Cornell Laboratortf of Omit:holoBq

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Chapter 4-What's Inside: and Pl1tjsiolo8tf organs. Their numbers vary directl y with the number of vertebrae in the vertebra l colurnn, which is genemlly related t o the size of the bird. For examp l e, the Rock Dove has 39 pair.; of spinal nerves; t h e Ostrich has 5 1. Spinal n erves differ in size according to their particular function. T h e large spi n a l nerves gover ning th e muscles of th e wings and legs fuse and b ranch to form networks or plexuses. Although we mention the spina l n erves here, in con jun ctio11 with the cent r a l n ervo u s system, they a r e actually part of the peripheral nervous system. Subd ividing the nervous system into two parts the ce11tral and peripheral-makes it easier to organ iz e the material for study But it is important to understCincl tliat n either the central n ervous system nor the periphera l nervous system can function by itself. Both are s impl y parts of one elaborately Integrated system t h at also includes the autonomic nervous system Autonomic Nervous The auto n omic n e rv o u s syste m Is not a ser ies of discrete and distinct structures as are the other systems consider ed here. Rather it i s a concept designed to facilitate understanding of the visceral nerve networ k and its physiologica l responses t hat operate w i thout conscious control. The system, which controls the "guts" as opposed to the "meat of the bird, is much more compl i cated than we describe. To most of the "rules" we present here, there are some exceptions. Even the most basic premise that the system i s without conscious control is not totally true. We know, for instance that some people c an voluntarily alter their heart rate and b lood pressure, and contr o l gastr i c secretion. Nevertheless, the concept of an autonomic nervous system is h e lpful to understanding how birds work. When first described the autonomi c nervous system was though t to be exclusive l y a motor system to the smooth muscle of various stru c tures But we now know that some of t he n erves involved c arry sensory iibers as well Each motor componen t of the autonomic nervous system is a two neuron cha i n, with a synapse between the neurons ( fig. 4-35).Th i s contrasts with the voluntary motor nerves { such as those of reflexes discussed above ) whose single cell bodies lie within the CNS. From the cell bodies ofthese vo l untary motor nerves, axons tun directly to the target muscle without any other peripheral neuron interposed. Thus the autonom i c 5 ystem while potentially a bit s lower than a simp l e voluntary reflex, i s capa l;>le of a great deal of subt l e modification outside the CNS. As in mamma ls, the bird' s autonomic n ervous system can be di vided into two segments on their regions of ori gin from the c e n tralner vo u s systerr as well as on thei r functions. The two divis i ons are the p a ra sympathetic system, with nerves originati ng in the crania l and sacral regions, and th e sympathe tic syst e m w ith nerve s ori ginating i n the thoracic and lumbar regions. Th e p a r asympathetic syst e m has its o ri gin in cranial nerves Ill VII IX, and X as well as from three sac ral spinal nerves. These n e r ves act o n smooth muscle to promote feedi ng, egg laying and other ''pea c e-of Bird Biolotl'l 4

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4 Figure 4-35 The Autonomic Nervou s System: This compleA br;mch of the nervou) ))!)tern controls the automatiC wnclions of the body's ;ntemal O!Jiims, .1ctinR primarily unconsciously. It con sist s of two subsystems, each of which innervates the same organs, but with op J1f1Sing effects. The sympathetic systom lions under conditions ofstre.> -fnr sp&>cling vp a bird's heartbeat Howard E. Evans and J B Heiser Cerebral Cerebellum .111d bteathing ratP hy means of the Lacrim.JI GJ;mct-----';...,"_,. neurotr.msmiuer epinephrine (adren-aline), to prt'(JJre for tigh t or flight The paras ympathetic system calms the bird, promoting feeding_ digestion, ;md other rt.'la\ ed activities. All s consist nf two neurons m sencs, but the organization of these neurons differs between the sym patheti c and parasympat h etic systems. Symp.1thetit neurons {Solid lines ) from the thoraci c and regions uf the spinal cord. The cell bndle> of the first sympathetic oeutons have migrated ovtslde tlw I cort.l. gathering int(>/1 sy mpathetic ganglion near the entml surface o( each vertebra ( see Fig. -1-JJ). A ch.1in of these ganglia runs the length of the pinal cord. The axons of the first sympathetic neurons run from the S)'m-p.thetic ganglion to ;mOiher g:mglicm (ope n clrdes) closer to the org;m being innervated, where they synapse with the cell bodies of the second sympathetic S tomach ncurons whose axons provide the tltMI link to the Wrget organ Par asympilthetic ncnmms (dashed lines ) origindte in the vagus .md o ther cranial nerves, ;md in the sacral region of the spinal cord. Celll>odlt.os of the first parasympathetic lnte!:ttnl' neurons rf!!iide within the brain or spi-n.l/ cord . mel their axons run a lithe w.1y to the organ, sometim<.>s a sreJt synapsing IVilh the second para;ympathetic neurons ( not shown). lcxated In or ne,Jr the target organ. --Sympathetic Nevron; ----Parasympatl1etic Neurons ; 0 Ganglion of Sympathetic Ganglion Cham (Cont;litls Cell8odi('S of Full Sympafhelic Neuronsl Ganglion Cont.1ining Cell Bodies of Second Sympathetic Neurons Cornell L.aboraton1 of OmttholoBtt

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Cllapter4-Wlmt's Inside: Anatomq and Phttsiolog'{ f ul ' activity Parasympathetic n erve stimul atio n quiets the bird. Some parasympathetic nerves carry impulses that reduce the h eart rate; others promote gastric secretion a nd peristalsis, thereby facilit a tin g digestion. In the parasympathetic system, the cell body of the first n euron lies withi n the brain or spinal co rd. Its axon must then pass into the organ being inn ervated before it meets the cell body of the second n euro n F i ring of the second neuron causes contraction of the smooth m u scle in the wall oftheorga n.Thusa vagal neuron ach for examp le, i s a ver y l o n g neuron indeed, leaving the brain and r eaching all the way to the wa ll of the stomach, where it synapses wlrh the second neuron of the pair In the sacral region the distance t hat the first n euro n has to reach is much shorter because t h e target organs are closer to the n erve or i g ins i n the s pina l cord. The sympath etic system co n s ists o f nerves that leave the spin<1l cord f r om t h e thoracic and l umbar levels. Sometimes called the ''fight o r flighe' system, it functions in e mergen cies. It s neurons speed up the h eart rate, i ncrease the b l ood pressure, provide deeper breathing, and allow for g reat e r muscular co nt raction. The sympat h etic system a lso dilates the pupil of t h e eye to produce that look of being "wide-eyed with frig ht." When the sympatheti c system i s activated, digestion s lows o r stops, and the bird may vom it or defecat e to better prepare its body for fight or flight Numerous seabirds, frightened at the nest, defecate or disgorge the contents of their c rop s or stomachs, som etimes most effective l y in the di r ection of the intruder! (See Ch. 6, Sidebar 3, Fig. D.) Vultures do the same from the air. In the sympathetic system, the cell bodies of the f irst neurons have migrated o ut s i de the I cord, w h e r e they for m visib l e nod u les close to the ventral surface of the vertebrae. These nodu les ( called sympat h etic gang I ia)appear as a chain because their axo n s may travel up or down paralle l to the vertebral column but just outside it, before passi ng to the i r target organs by runn i ng a l ong the surface of b l ood vessel s.Thece ll bodies of the second axo n sln a sympathetic c hain are grouped in v i sible masses, also called gang lia, on blood vessel s very close to the organs hefng innervated. As an examp le <.1 large c r a nial cervical gan gl ion is located on each side of the h ead/neck junction w here axons fro m the first n eurons (comi n g from the thorax ) synapse with the second neurons, which Innervate arter ioles of the head, caus ing their c onstr i ct i o n a n d therefore a n increase in blood pressure. The Senses V ision Sight is very important to b irds, which are thought to have the best vision among vertebrates. To provide w i de views and bright images, eyes must b e large Indeed, a bird's eyes a r e so la rge that someti mes their weight may equ a l or even exceed, the weight of the brain. The largest eyes of any land animal are those of the Ostrich (fig. 4-36), nearly two inches (50 mm) fn dTameter!Some birclshavethemostacute 4-45 I

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446 Figure 4-36. The Larg e Eyes of an Os trich: Among vertebrates hirds have the best vision, reflected by the fact that birds eyes are large sometimes equaling or exceeding the weight of the brain. TheeyesoftheOstrich, nearl y two inches (50 mm) in diameter, i/re th e l arg est of any land animal alive today. Photo b y H. Cruickshank/VIREO. Howar d E Evans atulJ. B Heiser (sh arpest or best r esolv ing) v i s i o n i n the an i mal k i ngdom. T h e Gold e n Eagle exceeds the vis u a l acu i ty of humans b y two or three times and i s capab l e of spott i ng movements of small prey such as r abbits from mor e t han a m il e awayl Unfortunately, t he desire t o know how o ur v i sion (or any of ou r other senses) compares w i th tha t of b i rds is fraught with obstacles. First of all, there are approximately 10,000 different species of l ivin g birds worldwid e a nd no blanket s t ateme nt ca n e n compass the v i s u a l abi I i t ies of them a ll. Second, we canno t experience the perceptions of other organ isms. W e must use indirect means-comparative anatomy, physiology, and behavior-to compare a bird's capabil ities to our own. Thi s is a trick y business but worth the try just how do avia n eyes stack up to ou r own? L e t's begin by examining eye struct ures. Th e Structure of the Eye In add i tion to the familiar uppe r an d lower eyelids, birds have a nictitating membrane or third eye l id. I t moves sideways across t h e eye, at ri g htan gles to the regu l a r eyelids, clean ing the eye's s u rface and keep i ng it moist ( Fig. 4-37; see also Fig 1 4 ) In so m e aq uati c b i rds s u c h as loons, cormorants, diving d u cks, and alcicls, the nictitatin g membrane has a specia l w indow-like area in the cente r These birds presumab l y "wear" their n ictita t i n g m emb r a nes as swi m gogg les to impr ove thei r u n derwater v i s i o n. Dippers, such as the Ameri can Dip per, h ave a n opaque, whit e thi r d eyelid w hich cu ri o u s ly. can be of n o use in sea r ch in g for prey und erwater. On each side of the eye are two t ear glands, w h ich m oisten the eye and nouri s h the cornea. One is the lacrima l gland, wh i ch lies i n t h e lower p art of the orbit and has many ducts that e nter t h e space betwee n the lower l id and t h e cornea. The other is the gla n d of the Cornell Laboratont ofOmitholoBIJ

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Clwpter 4-What's Inside: Anato11111 ar1d Phttsiolovtf third eyel id whi ch sec r e tes into t h e s p ace b etwee n the th ird eyelid and the co rnea. Tears fro m bo th glands drai n into lacr i m a l ca n a l s in thecorneroftheeye n ear thebeak an d n ostr11s to ente r the nasal c a vity. n,e eye b all (Fig. 4-38) has a tou g h oute r laye r of con ne ctive tissue, the sclera which i s s tiff e n e d by a ring of bon y scle ral ossicles (Fig 4-39) n ear t h e front of th e eye. Scleral ossi c les are p r esent in the eye balls o f all birds lizards, t urtles, and fi s hes. The a nt e rior surface of t h e opaque white sclera is s p ecialized as t h e tr a nspar ent cor nea, whic h a ll ows light into the eye. The l ayer d ee p to the sclera a n d c ornea is the vasc ul ar choroi d which forms the i r i s ( L a t in for "rainbow"), the co l o r ed p art we see w h e n we l oo k at a n eye (see F i g 3 34c). Th e Iris, which cont a ins smooth mu scle fibe rs, e n circles the o p ening o r pupil (see Fig 4-40) reg ula t in g its size and thus theamountofli g ht ente rin g the eye. W i t hin the eyeba ll the l argest cavity, the vitreous chambe r i s fill ed with a clear j elly-like hla teri a l the v i t re o u s body which in fl a tes' the eye and mainta in s its s h ape. Projecti n g into the vitreous b o d y fr o m th e site w h e r e th e optic n erve exits the eyeba ll i s a non-sen sory, vasc u l ar s tructure of th e choroid ca ll ed the p ec t e n. The pecten i s believed to n ou ri s h the r etina a n d to con tro l the p H ( acidity ) of th e VIITeou s b ody. Th e p ec t en takes m a n y i o rms, but ills present i n a ll birds and known elsewhe r e o nly f rom some r e pti les. The l e n s n crystallin eli ke s tru c tur e composed of regu l a rl y ori ente d layers of collagen fibers, i s the primary m o di f i er of focus. II i s spherical to ovoid in s hape depend in g o n the species and is u nusuall y soh and pl i a b l e i n compari so n with that of other vertebrates. Th e lens is esp ec i ally soft and plia b l e in man y d i v in g birds allowin g it t o be squeezed and stre t c h e d to a vari ety of s hapes, so It can achieve th e best po ssib l e vision under a vari ety of ci r c umstan ces. T h e l ens is held in place bet\.veen the v itreou s c h a mber an d the iris by ciliary processes O nl y in bird s do these processes attac h directl y t o th e l ens Ciliary muscles a tta c h to th e p r ocesses m oving the m w h en they contract. The l e n s -distortin g power o f these mu scles makes possible th e var i able-foc u s in g power s o f the l e ns. A small cha m be r in front of the l e n s i s pa rt ia ll y d i vided in two by the iris: a narrow po s t erior c h ambe r be tween t h e l e n s and iris; and a larger anterio r c h amber b e t wee n the iri s and th e cor n ea. Both c h ambers a r e fi ll e d w i th a queou s fluid, a ce ll fr ee fluid s i mila r to blood plasma (see Blood, later in thi s c hapter ) whi c h is co n s t antly produ ced from the blood and sec r eted into the posterior c h ambe r The aqueo u s fluid fro m the post e rior c h amber passes through the pupil into the ante rior c h amber n o uri s h i ng and removing wastes as it flows It then drains fnl o sinus spaces and veins at the base of the i ris to r e-ente r the blood. H andbook of Bird Biolo8'1 4 Figure 4-37. Great H orned Owl Show-I ing Nictitating Membran e: The nicti t .ltlllfl membrane, or third eyelid lies between the bircl's regular eye/icls ancl t/1e sur(ac e of the e ye. II moves ac ross the ev right an g l e slolheeyelids, cleanins ancllubri c atins the eye's outer surface.. In this ph oto i t i s visible halfwa y across the eye o f an immature Great Homed Owl. Photo b y Lang E lliatt/ CLO

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4 -48 a. Entire Eye Sclera b. Enlargement of Retina Optic Tract Figure 4-38. T11e In lema/ Structure of the Eye: The eye is positioned with the a nt erior .surface up i n both nlthese crosssec tiona/ v iew s a Entite Eye: Theeyeco n sistsof thr eemain layers, the sclera, cho roid and retina, which specializ-e to form various other stwctures. The tough, whitish oute r layer of r;onnective ti s sue is these/era. Toward the ante rior e nd oft h e eye1 the is stiffened by a b o n y ring of scleral ossiclcs, and across/ h e antednrsudace oft h e eye Ills m od it/eel tn become the (raMparent coroea The middl e laye r is the chotoid pi g m e nted <1nd ric hl y supplied with .blood vessels. I t forms the iris, the c olored part of the eye pupil ( see F'lg. 4-40). The c horoid a lsn forms the ciliary processes which attach to the l e n s a nd are moved u y the ciliary muscles thus altering the sllapeoft h e crys.-1.11/ine lens to fows imiJ8eS. The innermostl,7yer rs the retin;1, co n sisting of fisht-se nsitive cells ( see b). The larsecantral cavity within the eyeball, the vi t reous chamber is f/lltJd with a cleur, ;elly-likema teri,JI the Vitreous body, givf n g I he eyeball rigidity: T/Je pecten l'ound in a/( birds and a few reptiles, projec t s into L e n s Howard E. EvansandJ B Heiser Vitreous C hamber Filled with Vitreous Body the vitreous body, and is thought to n otlfish the retina and co n trol the acidity of the vitreous body. In front ofthe len.s is a small chami.Jer filled with aqueous fluid blld divid e d into /he anterior chamber and the posterior chamb er The .1queous fluid, a cell free fluid simllnr to blood plas ma, provid es nouris hment and removes wastes. b. Enlarge ment of Retina; The retina is mad e up u f light-sensitive cells, the rods and cuiJts, w hi c h contai n the visual pigments. Cone s are r espo nsible for visual acuity and the sensi n g of co/or iniormation. Rods are r elative/) insensitiv e to color, but the y d etec t low levels o( lig ht and thus are more Important than cnnes t n no cturnal birds. Neurons synapsing with the rOd> and co nes form the optic tract (also called the opt i c nerve), which forms a blind spot lwhe r e images cannot be d e t ec ted) on tl1e retin,7 as i t The poin t in the retina where the co ne.< are concentrated and vision i s sharpest is known as the cent r a l fovea. Main dr.1wing adapted from Proc t o r a n d L y nch (1993, p. 25 7 ) Inse t b y Chtisli Sobel. Com ell LAborotortt of' Omitholo8'1

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Chapter4-What'S Inside: and 4-49 The innermost layer of the eyebal l is the pigmented ret ina which consists of the lig h t-sensitive cells th e rods a nd cones. A bird sees an object when li ght from that object is refmcted as i t passes through the cornea, lens, and fluid filled c h a mbers, focusing an image on the r etina There, the rods and cones absorb some of the light's energy, are stimulated, and transmit the resultin g s i gnals to the brain via nl')rve imj:>I,Jises. Acuit y ( resolving power) depends on c lose pa ck i ng of the bright-light-sensfliv e cone cells. Th e packing of co n es in some regions of the ret in a of raptors may be as much as 650 million cells per square inch ( one million per squa r e mila. Cross-Sectio nal Views of Eagle and Owl Eyes limeter)! This Is five times the packing in the human retina. I n addition to being responsib l e for acuity, cone cells encode Information about the spectrum of colors conta in ed in the I ight focused on th e retina. Birds hav e four to five dis tinctive light-sensitive cone pigments plus specialized oil droplets in some cones that ma y function as filters, alterfng color sensitivity in the same manner as yellow, pink, or some other color of sunglasses. Humans have but thr ee lfght-sen sitive cone pigments and nothing comparable to th e avian oil droplets. Th e rods of birds are very sensit i ve to light en ergy, but are not capable of differentiating much in way o( co lor information Beca use they are good at detecting low POSTERIOR light levels rods are more i mportant than cones in owls and other nocti,Jrna l birds. We humans essentially lose our color vision from dusk to dawn seeing litt l e color differentiation even under brfght moonlfght, because t h e light i s too dim to stimulate our cones. b Ow/Skull Each rod o r cone cell has synapses w ith a compl ex of nerve axons, many of which pass to the brain. As i n all ver tebrates, the nerves from the sensory cells lle between the rods and cones and the pupil, blocking some of the light that would otherwise rea c h the sensitive cells. This appears to be a n inefficient way to construct a light -sen sit i ve organ, as the sensory ce ll l ayer actua lly interferes with vis i on. This arra n gement however, results from the evolutionary history of the vertebrate eye-evolution genera ll y works by modifying existi n g structures not by crea tin g new ones that are perfect for the job at hand Where the nerve l ayer is thinnest vision i s best. The axo n s of the neurons lead i ng from the rods and cone s pass over the surface of the re tin a and join to form the optic n e rve This nerve leaves the eyeball by penetral'ing the ret ina, choroid, and sclera and thus forms il "blind spot" in the midst of the retina where no rods or cones a r e present to ca pture light fall ing on that spot. In contrast, most birds likemostmammals, have in the ce ntral part of their retinas an a r ea, the centra l fovea where the cones are most con centrated and the neural layer thinned for the sharpest vision. Hawks and other fast-f l ying diurna l predato r s have, in add iti on, a nother s u ch area, the tempora l fovea in the posterior quadrant of the retina. of Bird Biolofjlf Figure 4-39. Scleral Ossicles: The eye's oute rmost layer, the sclera, is slifi'enetl by bon y rings called s cleral ossicles. a. Cross-Section
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4 50 Figure 4-40. Accommodation-The Mechanics nf T o shar p! > fn. r u s v arying dista n c e s o n the r etina, the e ) e c h a n ges the c urv.Jlltr e t 1 f the lens b y contracting and relaxing the ciliary w hi c h m o v e /he dliary processes 1 vh1c h e h a n ge the s hape of th e l e n s. These focusin g rl(ljustm e nt s are re(erre d co a s accommodation a Dis tant Vision: T o l o c u s dist.111t o bj ec t s the l en> flo/lens; al the s.1me lime, the pupil becomes wider. a/lowing more light into the eye b. Close Vision; r-ordoseobjcc/5 the l e n siJec:omes more rounde d ,md th e pvpi/ narrows. Drawings b y C harl es L. Ripper. a. Distant Vision; Pupil Wider; Lens Flatt e r How Birds See Howard E. Eva/15 andJ B Heiser b. Close Vision: Pupil Narrower ; Lens More Curved How does a bird use the structural featu res of Its eye to see? What information ca n help us jud ge how well birds see? Let's begi n by exam in in g t h e p r o cess of focusing. To allow t h e retina to obtain sharp images at varying distances the eye c h anges the c urvature of the lens (Fig. 4-40). This i s accomplished by the action of the ciliary muscles which move the ciliary processes, which exert p r essure on the lens. The len s flattens t o foc u s on objects far away a n d becomes more r ou n ded for objec t s close at hand. The c urvature of the cornea changes as well. These focusing adjustments are termed accommodation. At the same time1 the amount of light ente rin g the eye is regulated by changing t h e size of the plipll-opeh ing it for more light and closing it when there is too mu c h light. This is achieved through the act i o n of muscles i n the 1ris, w hi c h open and close the pupil j ust as the d i aphragm in a came r a contro l s the size of the aperture The next time you have the opportunity to examine a b i rd closely (try a parrot with its l arge easi l y observed eyes), watch t h e rapid c hange in its pupil diameter. The pupils first narrow to better see you in the foreground and t h en widen to keep tra c k of conditions fart h er away If you watch a f ri end doing the same visual task, the muc h s lower r esp onse ofth e human pupillary action will become evident. Many birds 5how a remarkab l e range and speed of accommod ation keep i ng obje cts ih focus at rapidly c hanging distances. A s tooping falcon for e x amp le, can keep prey in focus until it is in its talons. A warb l e r flying swiftly thro u gh a forest sees wel l enough ahead to avoid the trunks and bra n c hes of trees in its pat h. Some birds, on th e other hand are nearsighted (myopic), For e x amp l e1 penguin5 a r e notab l y myopic on land because the structure of their eyes is better sui ted to s eeing objects such as food in the water. (Water s refract i on of light Is so simil ar to thai of the eye tissues t h emse l ves that, when a bird is submerged, accommodation requires large, sp h e ri c a l inflexib l e lenses and corneas. ) Based on t h e presence 'and compl exity of th e cone cells, most d i urnal bird species are believed t o h ave very good color vision Ex perimenla l res ult s c onfirm thi s assumption, as color vision has been de m onstrated in a diverse set of birds including penguins pigeons Come II labofatorq of Ornitholoetf

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Chapter 4What5 Inside: A1wtom11 and Phttsiolo8tt ducks owls, hummingbirds and a number of passerines. Nocturnal species s u c h as owls probably have l ittle if any, color vision. In ad dition, many birds apparentl y ca n see certain types of ultraviolet l igh(, which is discussed in gre.1ter detail later in this chap ter. Many birdsindeed, many other vertebrates-see th e world very differently than we humans do, not because of differences 1n the internal anatomy of th e eye, but because of the placement of the eyes in th e he ad (Fig. 4-41 ). Many animals have primaril y monocular v i sion. This occurs when the eyes are situated on the sides of the head such that an object in the externa l environment can be seen only by one eye or the other but not by both eyes at the same time. In Contrast, when the eyes are located toward the front of the head, objects are seen with both eyes s imultaneous ly, resulting in binocular vis i o n The d i fferences between the two are rather like the difference between go Ing to a regu l ar movie versvs putting on t.hose r ed and b l ue glasses and watching a 3-D movie. Why then, is n't all vision binoc u l ar like ours? As with many biological alternatives, !rade-offs are involved. Monocular vision ca n be advantageous because it results in a w id e fi e ld of view, sometimes as much as 340 deg rees, which allows an anima l t o see both in front and in back at the same t Jme.ln co ntrast, a nimals with binocular vision, including humans have a much nar rower field of view because the visua l fields from each eye overlap extensively. Owl s with their binoct dar vision, can onl y see through a field of view of up to 70 degrees. A 8 A 4 Figure 4-41. Monocular Bin ocular Vision: The placement of the eyes on a /;Jird's h eild .'I !Teets the size and degree or overlap o( the right vi sual fields which determines rhl! extent uf binocular vision and thus depth per ceptfo n The circles shown here are the visu,ll fields of an American Woodcock t iel/) and an Eastern Screech-Owl trig hi/ at the horizont;J/ plane cor responding t o the line between point$ A and 8 marked on each bird. The eyes are on the sides of its /wad, giving it a field ofviewslighllygreatert.han 180degrees for each eye, bur only a small area of overlap t o the front a nd the mar. Bt>C"iliiSe bino c ular visio n occurs only w here the iielrlso(viewoverlap the wocxlcock hil S primarily monocular visio n Altlwugh its binocular vision is limited, this 5pecies hM complete monocular coverage of the hemisphere above and behind the heiJd, an tlrlaptation for spotting a pre dator ap proaching from m y direction The owl, Tn contr;.,st, has eyes l ocnted toward the fron t of the hflad. The 1/eld of view for each eye is therefore smaller than the woodcock s bll t the area where the vi sual fields overlap in front is far sreater. allowing considerab l e binocular vislun. n1is is crucial t o the owl for the successful cqp111re oi prey ; It is gained at a cost, howevet ,,s it leaves a blind area behind the owl' s head. 8 American WoodctJck Eastern Screec h-Ow( Edge o; Right Visual Field Area of8inoc ularVision '""" fdge of Leir Visual Field D Area of Monocula r Vision D 81indArea Behind Head Handbook of Bird Biolo.911

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I 4 Fig ure 4-42. A Common Snipe: A female Cnmmon Snipe is viewed from behind as it incubates on its nest. The snipe's eyes are set so far back on its head that its visual fields overlap more behind the head than in front. This produces a g r eater area of binocular vision to the rear than lo the front providing better protection agains T predators. Phoro by lvtarie Re.1d. Figure 4-43. American Bittern: The bittern's eyes are set/ow on the sides of its head. Thus. with the h ead h eld horizont,11/y. II can search the water below tor toad while also 5eei n g ahead. When a l armed th e bittern s tret c h es its head and neck high and points its hill directl y upward as picltlred here, blending in with the surrounding grasses !see Fig. 2-17/. Even in this defensive posture !he position of irs eyes permits good vision in front as well as of the sky overhead. Photo by Tom Vezo. Howard E. Evans a11d J B Heiser The eyes of I h e A m er ican Woodcock an d the Co mmon Snipe ( F ig. 4-42) are so far back on the head that these birds can see b et t e r beh ind than in f r o nt. Thi s may be a pro t ect ive feature fo r watching overhead for enemies while probing in the mud with its long bill. I n fact, many animals th at are frequently t h e targets of predators have monocular vision. Another bi r d with m o n ocular vision the American Bitt ern, ha s eyes set so low on l h e s ides of the h ead that it can look fo r food below a nd see a head at the same t i me. When alarmed a nd in a d efensive posture the bittern str e t c hes its h ead a n d neck h igh a n d points the bill straight up I n this position i t has good vis i on direct l y fo rward as we ll as upward into the sky (Fig. 4-43). Bin oc ul a r v i s i on a lso has a n i mportant a dv antage, h oweve r : it enab les a bird to h ave good d ep th perception an d t hu s t o determ ine d istances better. D e pth perception results from forward-facing eyes because eac h eye gets a sli g htl y d i f ferent view of an object ; the closer the object, t he m o r e d i ffe rent the two views. The difference allows the brain to d i sting uish d istance. Many predato rs, s u c h as hawks, eag les, an d owls, have b i nocular vision because i t aids them in c aptur in g p rey. A num be r o f b i rds with restri cted binocula rity but w i de monocu larityobta i n t heben efi tsof depth pe r cep ti o n by h ead actions. American Robins, p eeri n g at prospective foo d cock their heads at d i fferent a n g les before pickin g it up. They a r e making sure of its identity a nd captur e by determining its form a nd its pre cise three dimensio n a l posit ion. T he h ead bobbing a nd teeter in g move m e nt s of som e plovers and sand piper s may have the sam e fun c ti o n Watch a Rock D ove o r a ch i c k en as it walks, a l ternate l y jerki n g the h ead back and forth w ith pa uses in between m ove m ents. I n doing t his, the bird is getting a ser ies of different views fo r determ ining spati a l relationships of objects in its sur r ound ings. When th e bird's h ead moves backward r e l ative to its mov i ng body but w ith I i ttle mov e m ent r elative to th e v isua l scene, ac uity i s g r eatest. W h en the h ead m oves rapidly fo r ward, differe nces in the ap p are nt movement o f objects in t h e visual field give the Cornell Laboraton1 of Ornithologtf

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G1apter 4-What's Inside: Anatomq and Phtts ioloatt bird s tron g cues aboutthe three-dim e nsion a l positions of objects in its field of view ; during these h ead movements, objec t s close r to t h e bird appear to move across the v isual fi e ld faster than th ose at a distance. We experience a similar v i s u a l effec t when watchin g th e countrysi d e fl y by outthe s i de window of an automob i l e o r tra i n Birds th a t have both ce nt ral a n d t empo r al fove ae i n eac h eye ( usu ally predators), tend t o h a ve forward-dir ec t ed eyes for good b inocul a r visio n (Fig. 4-44). B ec ause images fro m eac h sldeoftheirfield of vlew ( th e regions they are passing throu gh) tend to fall on the ce ntr a l fovea it provide s acute monocul a r v i ews of these areas. Images from th e f r o nt the part of !he w o rld t h ey are about to ente r tend t o fall on the temporal fov e a prov iding acute binoc ular vision for that a r ea. Thus these predators s ee well on b ot h sides while a l so seeing ahead-an obviou s a dvantage when pursuin g pre y These multi pl e foveae a l so Monocular Field !Jinoc ular I Field ' I I I I ' \ .. : I ' I \ ' I I I I ' ... \ 0 I Dots Represent l
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I 4-54 Figure A Burrowing Owl Look ing at the World Upside Down: Unlike humans, birds can muve their e)1es very littl e in t/Jetr sockets. Owls /lave espeocially immovable eyes, but like other birds they compensate by havin g very flex.ibl e necks (see Fig. 4-1 J), Owls regularly tum their heads h a l(way around to ger a be11er view behind them, o r even view the world up side down, as this bird has c ho sen to rio. Photo by Bryan 5. Munn. Howard E Eva n s and J B Heiser c reate in c r edibl e compl exi t y for instanta n e ous neural p rocessin g and a na lysis! Some shorebirds whos e n o rm a l h ab it at is flat, o p e n and rel atively f eat ur eless, have a f ovea l str i pe that runs hori zontally across the retina. I t probabl y i s spec i alize d fo r d e t ect ing conditions, p articu l a rl y movement, alon g the horizon. Th e eyes of m ost birds m ove very littl e intheirsockets. B eca use of the eyeball's l a rge s ize, the r e sim p l y i s not much room in th e compa ct, s treamlined head for eye mus c les. The four r ectus and two obliqu e muscles that move the eye ball in a ll verteb r a tes, from f i s h to humans a r e present but muc h red u ced in size. Birds compensat e for the l ack of eye move m ent by havin g very mobile necks (Fig. 4-45) Owl eyes a r e immovably fixed in the s kull and they h ave o nl y tempora l f oveae, w hi c h a r e used for f o r wa rd b inocular vision. For v i ews to the s ides, they turn their h eads, som etimes h alfway a r o und. So, do bir ds see b e tt e r than hum a ns? As s h ou l d now b e e vident. m erel)'dec iding what we mean by better is a problem. Do we mean b ette r ac ui ty o r bette r foc us? Bet'ler l i g ht sensitivit y o r bette r col o r dif ferenti at i o n ? Toeach of these ind i vidual compo n e nts the a n swe r seems t o be "So m e birds yes, a n d some birds no. Under some c onditions some birds yes, b u t und e r oth e r con d i t i ons the same birds n o." Th at is a part of the m agic oi bird s No m atte r how hard we try their var i ety thwarts any attemp t to gene r alize. T h e best we may e ver be ab l e to do i s co nclude that some birds "see b etter" t h a n we do and that v i s i o n is the predominant sense of birds as a group. The Ear and Hearin9 Sound is a lso a n i m portant c h aracter i s ti c of the e nvironment, and its detection allows a bird to be co m e awar e of predator an d prey to f l ee i mpend i n g danger or a pproa c h poten tial mates, a nd to adve r tise or wa rn T h e challe n ge of hearin g 1s to con vert pressu r e waves i n the air (see Fig. 7-4) i nto neural impulses that ca n be interprete d by the bra in All anima l s do this by f i rst c h ang ing t h e varying pressure waves that m ake up sounds into vibratio ns, w hi c h are then a l tered f u rther t o become n erve impulses. Anima l s with the best hearin g ca n distin g uish the directio n o f origin, and the compl exity of freque n cy var iations as well. A bird's sense of hearin g i s keen and v ery im portant for surv ival and r e pr o du c tion. Th e ear had its evol u tionary origi n in f ishes as m embranous, fluid f illed chambers call ed the i nner ear which func tion i n m ainta inin g ba l a n ce a nd sensin g vibrations. For hea ring in air, amphibians, r eptiles, a n d bir ds all evolved additi ons to rhe f luid-fill ed c h a mbers. These included a n air-f i ll e d middle ear c h a mber w ith a s m all bo ne, the columella o r s t a pes, whi ch transm i t s Cornell Ltlb o r ator'1 of Ornitholoti'l

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Chapter 4What s Inside; a nd Phttsioloyq so un d vibrations to the inner ear from an ea rdrum whi c h stretches ac ross the external opening of the m iddle ear. These structures are dis cussed In more deta i I be l ow. Mamma I s carried the process eve n furth er by addi n g two more bones on each side, crea tin g a chai n offhreebones ( malleus incus, and stapes), and a sound-collecti n g a uricle or external ear -Lhe flap we see when we look at a mammal. Do not, however confuse the "ears" oi birds such as the Grea t Horn ed Owl and Long eared Owl w ith t h e birds' true ears (Fig. 4-46). The ears'' of these owls are merely tufts of feathers growin g from the top of the head1 and have n o relation to the tru e ears or to hearing. They are t h ought to be used in species recognition. Nevertheless, man y birds do have fleshy or feathery specia l iza tions (often modified au ri cula r f e a t h ers [ see Fig 1-51 or ear c overts ) around their e.xternal earopenings.Lil
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4 56 Figure 4-47 Asymmetrical Placement of lhe External Ear Cmals of a Boreal Owl: Marwspecies of owls have co nsiderable asymmet ry in the placement vf tl1e external ear ope nings, although the structures of the rnitldle and inner ii(n sound at e<1ch ear. Owls have I he sensilive acoustic systems oi i!ll IJirrls, enilb lin g some species, such as tl1e Barn Ovv/, to cap ture tlwJrprey in comp lete darkness. From Norberg { 1978) H oward E Eva11s and J B Heiser Right Ear I Boreal Owl Skull Anterior View Boreal Owl Skull D orsal View Left E;xternal Ear Canal sensitive ear s from loud sounds; alternatively, the fo l d can be erected to enhance the detect i o n of sounds coming from beh ind. Structure and Function of the Ear Let's now examine the three parts of the av i an ear-the external ear, the middle ear and the inner ear -in m ore detai I (Fig. 4-48). The external ea r ca n a l leads to the t ympanic m embrane or eardrum. The eardrum, stretched t aut over the ear ca n a I vibra tes w h en struck by the pressure waves of a sound. Th e ea rdrum's movement i s then transferred Figure 4-48. Location ,1nd Structure of to a pisto n-like m ovemen t of the s l en d e r columella bone, whi ch is at Roc k Dove Ear: The avian ear consist;;< of three parts: the external ear, the middle ear and the inner ear. Jll embedd&d In hone. As in hvmans and many other an imals, the external earcan.1l (not shown } leads (rom outside the !Jody 10 the t y m panic membrnne or eardrum Attac hed to the Inner of the eMdrttm is ' slender hone, /he co lvmel/a, which ex lends I! cross tlw snta/1, air-filled c hatnber of the middle mr. A t a pliable spot known as the vestiblllar windOH', the colvmell(l contacts the bony, /luid-ii/ l ed inne r ear (see Fig. +49), where the organs uf hearing and l>alance reside. Reprintecl from Manua I of Ornithology, hy Nohle S. Proctor :md Patrick). Lynch, with of the publisher. Copy righ t 7993. Yale Urriversity Press. Comell L.aborato"t o(OmitholoB'I

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Chapter 4What's Inside: Anatomtt and Phttsiolo811 tac h ed t o the interio r s ur face of t h e ea rdrum. The a r ea inte rna l to the eardrum w h i c h includes the col umella is termed the middl e ear; it i s a small, ai r-fi lled cavi ty, bou n ded by bon e and o p e n to the throat via the auditory {Eustachian) tube. In birds the auditory tubes join and e nter the caudal roo f of the mouth t hrou g h a common opening Perhaps you have e xp er i enced pressure o n your eardrums when climbing a mountafn or being pressurized in a n airp l a n e You ma y h ave relieved the p ressure by either blowing yo u r n ose, yawning, o r swallowing. For a bird constantly c h ang in g its a l titude in fli g ht the n eed to eq uali ze t h e pressure in t h e middle ear with that of the external ea r must be almos t con stan t. The audito r y tubes permit this eq u alization a l lowing a i r taken in the mouth (and thus at the sam e pressure as ambie nt air and the air in the ex t erna l ear canal) to move in or out of the middle ear until eq ual background pressure is e s tablished o n both sides of t h e eardru m. The co lum ella across the middl e ear cavity to contact a soft, pliab l e spot, the vestibular window ( form er l y ca l l e d ova l win dow), o n the bony inner ear (Fig 4-49) Unlike the ex t e rn al a n d middle ear whkh a r e filled w ith air, the inn e r ear is f ille d with f luid. Its ent i r e s tru c tur e is that of two fluid fil l ed syst ems, called labyrinths o n e w i thin the other. The i nner "s ac i s ca l l e d the membra n o u s l a b y rinth and is filled with a fluid ca ll e d endolymph.A bony laby rinth fi ll ed with a fluid ca ll ed p erilymph, e ncases the m e mbran o u s la by rinth; thu s the de l i cate membranou s labyrinth f l oats in the p er i lymph and is well protected. This protection is essent i a l beca use t h e se n sory ce ll s for eac h p art of the inner ear (te rm ed hair cells) are l ocated o n the inn e r surface ofthe m e mbranou s labyrinth These sensory cells send messages to t h e b r a in v i a the eighth (vestibulocochlear ) cra ni a l nerve. T h e Inn e r ear has three m ajo r regions: (l) rhe bony cochle a e n clos i ng the membranous cochlear duc t (2) the bony s emicir c ular canals, surrounding membrano u s semic ircular duc ts, a n d (3) the b ony ves tibul e which e ncases two chambers calle d the utri culus and s ac culus part of the m e mbranous labyrinth. Th e first region is concerned with hearing and the second and third a r e con cerned with the sen se of balance or equilibrium. The coch l ea of birds is a n e l ongated structu r e containin g t hr ee flufd fil l ed canals {Fig. 4-50 ). (In m ammals the cochlea i s curl e d like a snail's s h ell, t hu s givin g rise to t h e name, w h ich mean s "snail" in Latin.) T h e upper and lower ca n a l s (ca l l e d vestibular and t ympanic canals resp ective l y), connected at o n e e nd are part of the bony lab yri nth and therefore contain perilymph. B etwee n them is the coc hlear duct, part of the m embran ous l abyri n t h filled with endo l ymph. The lower m emb r ane of the coc hlear duct i s cal l ed the bas ilar papilla and lying close above it is the tectorial membrane; all along the basil ar papil l a are sen sory hair cells. R ecall that sou nd waves in the air vibrate the eardrum which Lransfers its motion t o the thin toothpick-li ke columella. The colum ella m oves the ves tibu l ar wfndow and sends pressure waves through the perilymph of t h e coch l ea and e ndol ymph of the cochlear duct. The basilar papilla is set into motion b y these pressure waves, moving 4-57 I

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I 4-58 a labyrinths of t he Inner Ear Bon)' Labyrinth Pefilymph Endalymph Membranous labyrinth c. Internal Structure of the Ulric:ulus and Sacculus STAT/CEQUil/BRIUNI HEAD UPRIGHT 1-lafrCe//s NEADTJI.TED Vestibule Figure 4-49. Slru clure and Functions of the Inner E ar: n1e bonv, fluid-iil/c..J inner ear h,1s three major parts; rhe semicir mlar canals and the ves t ibule both of which control bal mce ( equilibrium) and the cochlea whose role is in hearing, The columella of the mir;lr;Jle ea1 contar;(..< the sunface of the bony labyrinth / sec [ a } below ) at the vestibula r window (formerly called the oval window), a pliable region marking the base oi the cochlro. t \ so(tspot the c ochlear window (formerly called the round window), is loc.1ted nearby. The cochlea and the mechanism of hearing a r e described in Figure 4-50. The three are ammged appro1
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Chapter 4 What's Inside: AnatomtJ aJ!d Phi[Slolo[N t h e hair cells agai n s t the tecto r ial membrane and triggering a nerve impulse in the affected hai r cells. Differe n t f requencies of sound cause different po r tions of the basilar papilla to vibrate-the h i gh est frequ encies causing g r eater movement in the pro>'imal end of t h e membrane ( near t h e vest ibu lar and cochlear windows). The brain de ter mines p i tch by registering whtch region of hair cells are stimulated (Fig. 4-51 a ) and is t ho u ght to determine tone (the qua I ity oL1 sound) by the distribution of hair cells s1imulated. T h e volume ( loudness ) of a sound is determine d by the amount of pressure of the sound wave. Loud sounds cause more vigorous vibratio n s of the eardrum and thus of the flu id in the cochlea, and the resul ting i nc reased stimulation of hair cells i s interpreted by the brain as a l oud no ise (Fig 4-5 1 b ) AL t h e end of t h e bony l abyrinth farthest from t h e vestib u lar w i ndow is a second soft spot J t h e cochl ear w ind o w (for merl y called the round wi n dow), wh lch abuts the dead space o( the middle ear (see Fig. 4 50). The co c hlear window acts both as a pressure-release valv e and as a damper for the waves i n the cochlea. Each vvave i s dissipated as it expends its remai n ing energy distending the coch l ear window membrane into the middle ear, preparing the inner ear to receive n ew pressure waves f r om new sou nds. The struct' u res of the i nner ear are prote cted (rom very loud sounds by the action of a smal l muscl e thal e nlers the midd l e ear cavity from the outside and attaches to the col umella. When a loud Plan e o f Section Thr ou g h Cochlea Sound Pressure \!\lave rl1rough Fluid Handbook of Bird Biolofl'l 4 Figure 4-50. Internal S t r u c ture a nd Hear i n g Mechanis m o f the C ochl e a: The I cocil/ea of birds is an e lon gated struc-ture contai ning J7uid-fil/ed canals. Two of them, the v e s tibular can a l a nd the ty mp a nic c an a l connected to each other at the lip or the cochlea are part or the bony lahyrinth, and therefore con-tain perilymph. The endol y mph-filled c ,lfla l between them (tht c o c hlear du c t part or' thl! mombrannvslabyrinth ) consists or a membrane, the basila r p apilla illong which lie numerous sensory hair eel/; overlaid by anot her membrane the tector i a l m e mbran e The hair cells am at the of the cnc hlea, becnming longer t owarc l ;ts tip The flex-ible vest ibular w indo w M whio lt the colunu:lla of the middle ear contacts the cochlea, lies a t the base ( pmximal end) of tln 1 vc.>sti bttlar eanal. l'learby, ,11 thebaseofthetympanic canal i$ the co-chi eat Wind ow. Sounds are perceived in tile followmg way: Sound waves through air vlbmte theeardrwn, and this m otio n is transferred t o the colvme lla which in wrn vibmt es against the vestibui;Jr window (dashed arrows), sending sound pressure wavel' (solid arrovs) through the perilymph of the cochlea and the endolymph ol the ooc h/ ell( duct. Dif(ert'nt {requencie)' of cau se {l{fterent portions or the basilar P lpii/J to move moving certain hair cells against the tectorial membrane .1nd bending them triggerit1g nerve impulses. The impulses are transmi tted throug h the vestib u/o coch l ear /auditory) tmve to the brain where they nre interpreted as sound The 1/e.
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4-60 Figure 4-51. How Pitch and Volum' (Loudness) are Perceived: a. Pitch: Sounds of difierent pi(dle$ !frequen cies) are distinguished by t h e r:och /ea bec11use sound pressure waves of a given frequency travelling through t he fluid of the coc h lear duc t use a specific region ,1long the basiliir p.1pilla to vi/Jrate more strong l y than o t her resions, /)lOVing it.< .Jt tac hecl hair c ells agalnsllhe t ectorial membr to'At;;ud the dist a l end. b Volume: Volume(/oudnt>ss) is il limction of the arryplitu d e ( height ) of the sou n d \vave. The g reater th e amplitude of il sound, the mnre vigorous t h e villrillions of the fluid i n the cochle.1, u n d (lws the g;e,Jter tl1e di5pi,Ken1ent (l>en ding)oftl le hnir cells along the basi fur papilla S t ronger s t imulation of the hair cells results in more nerve impulses wllic/r tire brain interprets as sour1d oi <1 higher vol ume a. Pitch Basilar Papilla \ BASE (l'roximal) 24,000 lIz I ,OOOHr b Volume (Loudness) Bas!J,lr Rtpilla \ BASE (Proxinml) Howard E. Evan s and j. B Helser 5001-lz TIP ( Distal ) TIP ( Dis t ill) 1-J/gh Frequ e n cy Soun d / .ow Frequen9 Soun d Nigh Volume Soun d Low Volume So u nd noise i s r ece i ved, Lhis muscle con t racts, r estrict in g tra n smissi o n o f th e full i o r ce oft h e e a rdrum's v i b r a t io n to the inn er ear, the r eby pro tecting lt. I n all ve rt ebrates, [h e inn e r ear func t i on s I n ba l ance as w ell as i n hearin g, but the se nse of ba l a n ce i s e sp ec i a ll y importa nt t o birds b eca use of the three-dime n s i o n a l ac rob at i cs o f fl i g ht. B a l a n ce has two compo nents: d y n amic, th e p e r ce p t i o n o f m o tion : and s t a t ic, th e p e r cep ti o n of g r av i ty Th e semicirc ul a r ca n a l s and ducts fun cti on in dyn am i c balance, a n d t h e vestibule, in s t a tic bal ance. Th e n a rr ow, rin gl ike semicirc ul a r ca n a l s a nd t h ei r e n close d duc t s are arr a n ged at app roxim ate l y righ t a n g les to eac h oth e r so th at o n e i s l ocated in each of the th ree pla nes of space (see Fig 4-49). The base o f eac h sem i circ ular duct (calle d th e ampulla) i s wide n e d and conta in s C ornell Labo r a t on1 of'Omitho lo&tt

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Chapter 4What's /nsTde: Ana and PIUjslolo!JI.f hair ce ll s embedded i n a ge l atinous material, sur rounded by endo lymph. When the bird c h anges its speed or direction (accelerates), the endolymph in the canals lags behind (