The effects of forest fragmentation on avian nest predation in the Monteverde region


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The effects of forest fragmentation on avian nest predation in the Monteverde region

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Title:
The effects of forest fragmentation on avian nest predation in the Monteverde region
Translated Title:
Efecto de fragmentación de bosque en depredación de nidos de aves en la región de Monteverde
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Gibbons, Sara
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Birds—Nests
Aves—Nidos
EAP Spring 2018
EAP Primavera 2018
Costa Rica--Puntarenas--Monteverde Zone
Costa Rica--Puntarenas--Zona de Monteverde
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Habitat fragmentation is the division and reduction of a large, continuous area of habitat into smaller pieces. In nearly all cases tropical rain forest fragmentation has led to a loss of local species due to an increase in predators, a shift in microclimate, and a decrease in habitat area. Forested avian species are especially affected, showing a significant decrease in abundance and nest success in forest fragments. I investigated the predation rates on thrush nests in two fragmented sites. The first site was La Calandria, which is an isolated forest patch. The second site was Bajo Del Tigre which is a larger, more connected forest fragment. I placed 15 artificial nests along three transects in each site for a week to observe predation. I found a higher predation rate in the smaller, more isolated forest fragment. The type of predation varied between the fragments, suggesting different predator composition between isolated fragments and continuous forest. Also, there was no relationship between the distance from the edge and the predation rate; however, this may be due to the limited distance studied. There was a direct decrease in predation as the density of plant coverage around the nests increased. No relationship was found between the density of plant coverage and distance from the edge. These findings have important implications for conservation efforts, and suggest that fragmentation can be a threat to bird egg survival. ( , )
Abstract:
La fragmentación del hábitat es la división y disminución de un área grande y continua de terreno en partes más pequeñas. En casi todos los casos, la fragmentación del bosque tropical ha causado la pérdida de especies nativas debido a un aumento en los depredadores, cambios de microclimas y la disminución de hábitat. Las especies de aves de bosque son especialmente afectadas y se ha encontrado una disminución significativa en la abundancia y el éxito de los nidos en los fragmentos de bosque. Investigué las tasas de depredación en nidos de zorzales en dos fragmentos. El primer sitio fue La Calandria, que es un parche aislado bosque. El segundo sitio fue Bajo Del Tigre, que es un fragmento de bosque más grande y conectado a más área boscosa. Coloqué 15 nidos artificiales a lo largo de tres transectos en cada sitio durante una semana para analizar su depredación. Encontré una mayor tasa de depredación en el fragmento de bosque más pequeño y aislado. El tipo de depredación varió entre los fragmentos, lo que sugiere una composición de depredadores diferente entre los dos fragmentos. Por otro lado, no hubo relación entre la distancia desde el borde y la tasa de depredación; sin embargo, esto puede deberse a una corta distancia del borde seleccionada en este estudio. Hubo una disminución directa de la depredación a medida que aumentó la densidad de la cobertura vegetal alrededor de los nidos. No se encontró relación entre la densidad de la cobertura de la planta y la distancia desde el borde. Estos hallazgos tienen importantes implicaciones para los esfuerzos de conservación, y sugieren que la fragmentación puede ser una amenaza para la supervivencia de huevos de aves.
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Student affiliation: Department of Environmental Studies and Biological Sciences, University of California, Santa Barbara
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Monteverde Institute
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Gibbons 1 The e ffects of f orest f ragmentation on a vian n est p redation in the Monteverde r egion Sara Gibbons Department of Environmental Studies and Biological Sciences University of California, Santa Barbara EAP Tropical Biology Spring, 2018 June 8th, 2018 ABSTRACT Habitat fragmentation is the division and reduction of a large, continuous area of habitat into smaller pieces. In nearly all cases tropical rain forest fragmentation has led to a loss of local species due to an increase in predators, a shift in microclimate, and a decrease in habitat area. Forested avian species are especially affected, showing a significant decrease in abundance and nest success in forest fragments. I investigated the predation rates on thrush nests in two fragmented sites. The first site was La Calandria, which is an isolated forest patch. The second site was Bajo Del Tigre which is a larger, more connected forest fragment. I placed 15 artificial nests along three transects in each site for a week to observe predation. I found a higher predation rate in the smaller, more isolated forest fragment. The type of predation varied between the fragments, suggesting different predator composition between isolated fragments and continuous forest. Also, there was no relationship between the distance from the edge and the predation rate; however, this may be due to the limited distance studied. There was a direct decrease in predation as the density of plant coverage around the nests increased. No relationship was found between the density of plant coverage and distance from the edge. These findings have important implications for conservation efforts, and suggest that fragmentation can be a threat to bird egg survival. Efecto de fragmentacin de bosque en depredacin de nidos de aves en la regin de Monteverde RESUMEN La fragmentacin del hbitat es la divisin y disminucin de un rea grande y continua de terreno en partes ms pequeas. En casi todos los casos, la fragmentacin del bosque tropical ha causado la prdida de especies nativas debido a un aumento en los dep redadores, cambios de microclimas y la disminucin de hbitat. Las especies de aves de bosque son especialmente afectadas y se ha encontrado una disminucin significativa en la abundancia y el xito de los nidos en los fragmentos de bosque. Investigu las tasas de depredacin en nidos de zorzales en dos fragmentos. El primer sitio fue La Calandria, que es un parche aislado bosque. El segundo sitio fue Bajo Del Tigre, que es un fragmento de bosque ms grande y conectado a ms rea boscosa. Coloqu 15 nidos a rtificiales a lo largo de tres transectos en cada sitio durante una semana para analizar su depredacin. Encontr una mayor tasa de depredacin en el fragmento de bosque ms pequeo y aislado. El tipo de depredacin vari entre los fragmentos, lo que sugie re una composicin de depredadores diferente entre los dos fragmentos. Por otro lado, no hubo relacin entre la distancia desde el borde y la tasa de depredacin; sin embargo, esto puede deberse a la una corta distancia del borde seleccionada en este estud io. Hubo una disminucin

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Avian Nest Predation in Forest Fragments Gibbons 2 directa de la depredacin a medida que aument la densidad de la cobertura vegetal alrededor de los nidos. No se encontr relacin entre la densidad de la cobertura de la planta y la distancia desde el borde. Estos hallazgos tienen importantes implicaciones para los esfuerzos de conservacin, y sugieren que la fragmentacin puede ser una amenaza para la supervivencia de huevos de aves. Species evolve and adapt to best fit their environment through the process of natural selection. A ltering the specific microenvironment a species is adapted to can lead to their elimination in that area (Norton, 2002). Humans have been modifying habitats at rates that exceed the ability for most species to adapt and respond (Didham, 2010). One major re sult of anthropogenic habitat destruction is forest fragmentation. Habitat fragmentation is one of the biggest contributors to “population decline, biodiversity loss, and alteration of community structure and ecosystem functioning” (Didham, 2010). By dividing the area into two or more segments, the amount of edge habitat considerably increases while interior habitat is reduced. The interior and edge habitats differ dramatically in their microclimates; the edge has “greater fluctuations in levels of light, t emperature, humidity, and wind” (Primack, 2000). These rapid changes , or edge effects, put significant pressure on species and drastically alter the original composition of the environment. Fragmentation also increases the vulnerability of the area to nonnative species due to the higher amount of open edge habitat (Primack, 2000). By exposing more of the forest area, new species that could not previously gain access to the habitat are now able to enter . These possibly invasive species are often predators that eat the eggs and nestlings of forest birds , potentially causing harm (Primack, 2000). Previous findings have demonstrated that some bird species are negatively impacted in fragments ( Sodhi et al ., 2011, Nour et al., 1999). M ore specifically, s even out of eight understory birds in t ropical forests fragments have shown a decrease in abundance and nest success (Newmark and Stanley, 2011). The potential increase in predators, shift in microclimate, and decrease in habitat area all may contribute to this decline, however, the specific cause is still unknown. One explanation could be an increase in predation, especially since nest predation has been found to be the leading cause of nest failure in other understory birds (Crick et al., 1994, Siepielski et al., 2001, Thompson, 2007) . For example, 665 yel low w arbler (Setophaga petechia) nests were examined for nest survival, and 77% of nest failures were attributed to predation (Latif et al., 2012) . This shows that predation is a significant threat to bird nests, and opening the habitats to more predators could affect the bird populations within these areas. The central focus of this study is what effect does the level of fragmentation have on the predation rates of avian nests? Not only is the predation ra te important, it is also vital to evaluate what type of predators are attacking the nests and may be contributing to this decrease in nest success. It has also been shown that there is a significant decrease in nest success near the edges of the fragments compared to the interior habitat (Ribeiro and Penido, 2015). This leads to my next question: how do edge effects influence the predation rates on avian nests? This could help determine if edge effects are causing an impact on the nests and how far into th e forest these impacts can be seen. Another factor being considered in this study is the amount of plant coverage surrounding each nest. Nests can be more easily detected by visual predator s in open areas since there is less plant coverage to hide them ( Bakermans et al ., 2012). The last question being studied is how do changes in density of plant coverage affect predation rates, and how

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Avian Nest Predation in Forest Fragments Gibbons 3 does this density vary with the distance into the fragment? Answering this question can help determine if the decrease i n nest success is influenced by the level of visibility to predators, and if the edges contain a different level of visibility than the interior habitat. MATERIALS AND METHODS For this study 30 artificial bird nests were constructed and placed in two forest fragments from 20 May 2018 to 27 May 2018. The first fragment was Bajo D el Tigre, which is 29 hectares but is attached to the Children’s Eternal Rainforest , which is 20,000 hectares. This gives the fragment more connectivity and forest cover . The second site was La Calandria, whi ch is 27 hectares and is completely surrounded by pastures and residential area, making it isolated from other forest areas. Both sites are approximat ely at the same elevation to ensure that the predation would not vary due to change in altitudinal gradients. I placed a total of 15 nests in each site along three transects. The transects followed parallel trails in each fragment, which were different dis tances from the forest edge (Appendix A). Each transect contained five nests which were placed 15 to 20 meters apart. Transect A was located approximately 25 meters from the edge in both sites. Transect B was located farther into the fragments, approximately 75 meters into La Calandria and 85 meters into Bajo Del Tigre. Transect C was the farthest from the edge of the fragments, approximately 150 meters into La Calandria and 170 meters into Bajo Del Tigre. To construct the nests, I used 30 small plastic bo xes that were 10 x10 cm . They contained holes in the sides for water drainage, and an additional hole was made on the bottom of the box to ensure the nest would not flood during high rainfall. Using gloves to prevent the transfer of human scent, I collected twigs, grass, and mud from the area surrounding the Biological Station in Monteverde and the Monteverde Institute. The mud was used to help adhere the grass to the box and dull the unnatural yellow color . I added a handful of dried grass to each box to cover the interior area. I then used twine to tie twigs to the top of the box in the shape of a circle. The nests all contained three eggs (Figure 1). One was a real quail egg to attract predators by smell. The other two eggs were constructed out of white plasticine by rolling them into a circular shape similar to the size of the quail egg. The plasticine eggs were completely smooth prior to placing them in the fragments. A total of five feathers, each about 3.5 centimeters long, were added to each nest to add a natural bird smell. The nests resembled the nests of the Turdidae family since they are common in the Monteverde region and many were nesting at the time of the experiment. The finished nests were placed in trees at an average height of 1.26 meters. The height ranged from 0.91 meters to 1.57 meters, which was chosen since Turdidae nests are typically found in “lower branches of a sapling or shrub, where a fork provides good support” (Powell, 2012). Twi ne was used to secure the nests to the branches. I checked the nests every day for signs of predation, being careful to not touch the nest to prevent the transfer of odors. I collected the eggs a s soon as two or more in each nest displayed visible signs of predation. These include d holes in the eggs, claw or bite marks, cracks, fallen eggs, and missing eggs. The marks left on the plasticine eggs were used to identify what type of predator had attacked the nest. I also placed two camera traps in order to help identify the specific species preying upon the nests. The nests were left in each site for a total of seven days.

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Avian Nest Predation in Forest Fragments Gibbons 4 In order to determine the density of plant coverage, I cre ated a scale with ratings from one t o five based on how hidden the nests were. A score of one represented the lowest density of coverage around the nest and a score of five had the densest coverage. I accounted for the plant coverage on all sides of the nest (front view shown in Appendix B). Figure 1: Example of finished artificial nest placed in La Calandria R ESULTS There was a higher predation rate in the isolated fragment compared to the larger, more connected fragment. In La Calandria 60% of the nests showed predation. In Bajo Del Tigre 40% of the nests showed predation (Figure 2). This predation was caused by large birds, small birds, squirrels, and unknown predators. All of the predation events in La Calandria were caused by large birds. For Bajo Del Tigre, 66.7% was caused by small birds, 16.7% by squirrels, and 16.7% is unknown due to the lack of plasticine eggs present (Table 1). Figure 3 shows there was no clear relationship between the predation rate and the distance from the edge of the fragment. The density of plant coverage surrounding the nests was related to the predat ion rate; as the density increased, the predation on the nests decreased. This data best fits an exponential regression with an R squared value of 0.996 (Figure 4). There was no clear relationship found between the amount of plant coverage and the distance from the edge of the fragment (Figure 5).

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Avian Nest Predation in Forest Fragments Gibbons 5 Figure 2: Rate of predation on the artificial nests in La Calandria and Bajo Del Tigre (n=15 per site) Table 1: Predators of the artificial nests in each site (n=9 for La Calandria, n=6 for Bajo Del Tigre) Predator % Predated Eggs at La Calandria % Predated Eggs at Bajo Del Tigre Large Birds 100% 0% Small Birds 0% 66.7% Squirrel 0% 16.7% Unknown 0% 16.7%

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Avian Nest Predation in Forest Fragments Gibbons 6 Figure 3: Predation rates on artificial nests at various distances from the edge of the fragments (n=5 for each transect in each location) Figure 4: Predation rates on artificial nests with different plant coverage densities (n=8 for density 1, n=8 for density 2, n=7 for density 3, n=4 for density 4, n=3 for density 5 )

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Avian Nest Predation in Forest Fragments Gibbons 7 Figure 5: Average density of plant coverage at each transect in La Calandria and Bajo Del Tigre (n=5 per transect at each site) D ISCUSSION Figure 2 showed that in La Calandria the predation rate was 20% higher than in Bajo Del Tigre. This was expected since the smaller, isolated fragment contains more edge habitat, which makes it easier for nonnative species to enter (Primack, 2000).Thes e nonnative species are potential new predators gaining access to the forest and could account for the higher predation rate . Although predation is a natural process that is necessary to mai ntain healthy population sizes, a 20% increase in thrush egg predation could have a significant effect on their survival in the Monteverde reg ion. The abundance of thrush species in the two fragments is not known, and more research is needed t o know how much of an impact this increase in predation would have. This could have important implications for conservation efforts trying to protect avian species in the area. Additional studies should be conducted, but it is clear that larger, more connected fragments show a lower egg predation rate . This suggests it could be beneficial to focus conservation efforts on protecting larger areas or establishi ng corridors in order to reduce the predation rate on cuplike nests. The predation in both sites was found to be largely caused by birds. In La Calandria, all of the eggs were preyed upon by large birds, signified by large beak marks and the eggs being moved outside of the nest (Appendix C). In Bajo Del Tigre, the eggs preyed upon by birds had different marks, indicat ing smaller birds as the predators. The most distinct marks of these preda tors consisted of small holes from the birds pecking the eggs and small beak marks (Appendix C) . Also, more of the nests still contained eggs. This is likely because the smaller birds could not carry the eggs outside the nes t due to their size and weight. Bajo Del Tigre also had squirrel predation, easily identified by the teeth marks left on the egg (Appendix C). The exact condition of each nest can be found in Appendix D . This difference in predation is notable, especially w hen considering that large birds were responsible for all of the predation on nests in the isolated fragment. The most likely bird

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Avian Nest Predation in Forest Fragments Gibbons 8 responsible for this predation is the great tailed grackle ( Quizcalus m exicanus) , but brown jays ( Cyanocorax morio) are also a potential predator. Both are present in La Calandria and both are known to be nest predators, but brown jays only “occasionally pillage the nests of smaller birds” (Stiles and Skutch, 1989). In addition, grackles prefer humanmodified environments, which is the habitat that surrounds La Calandria (Wehtje, 2003). Further support for grackles is that they are absent in Bajo Del Tigre where there was no large bird predation. However, brown jays are present in Bajo Del Tigre, meaning that large bird predation could have been present in this site if they were the cause. There are also other cases of invasive birds causing high rates of nest predation. Black robins ( Petroica traversi ) build cuplike nests in the understory, similar to the nests in this study, an d nest predation from the invasive European starling ( Sturnus vulgaris ) was the largest cause of nest fai lure (Massaro et al., 2012). This shows that other invasive birds have been found to be the main predators on cuplike nests. The refore, the high predation in the isolated fragment was like ly caused by invasive grackles. H owever, more research is needed to find out the exactly what is preying upon the nests. One of the camera traps located in La Calandria caught a Rufousandwhite Wren (Thryophilus rufalbus) approaching one of the nests (Appendix E). There was no predation on the eggs after this event, but it is important to note since they are a potential cause of egg mortality . W rens are unique since they do not consume the eggs they kill, instead they only peck and remove them from the nests. This egg destruction is to increase their nest success by eliminating their competition (Belles Isles and Picman, 1986). The wren may not have destroyed the eggs in this nest for many reasons, however, the presence of the bird approaching the nest is important since these are a potential cause of egg mortality in both La Calandria and Bajo Del Tigre. This study focused on the predation of cuplike nests resembling the Turdidae family. It is important to not e that other types of nest architectures could survive differently in these forest fragments and have different predators. Newmark and Stanley (2011) investigated the nest success of four different types of nests in tropical forests, including cuplike, pl ate, dome and pouch nests. They found that there were different survival rates of the different types of nests, and that cup like nests were the most vulnerable architecture. This suggests that other types of nests may have different predation rates, but m ore research is necessary to determine these relationships in the Monteverde region. Figure 3 illustrates that there is no clear relationship between the distance from the edge and the predation rates on the artificial nests. This could be due to the abs ence of edge effects, or it could mean that the study did not go far enough into the fragment to see a difference between edge and interior habitat. The distance studied was from 25 meters to 170 meters into the forest, suggesting the edge effects may be p resent to 170 meters, if not father, into the forest fragments. Other findings report that edge effects are often evident up to 250 meters into the forest (Primack, 2000). This could explain why there was no difference between the nests at varying distances from the edge in this study; however, more research is needed to determine the presence of edge effects in the Monteverde region. There was a clear relationship between the density of plant coverage and the predation rate on the nests. As the density of plant coverage surrounding the nest increased, the predation rate decreased. This wa s expected since the more hidden each nest is, the harder it is for vis ual predators to find the nest. The data presented in F igure 4 accurately represents this relationsh ip,

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Avian Nest Predation in Forest Fragments Gibbons 9 signifying that density of plant coverage could be a good indicator of the predation rate on cuplike nests in the Monteverde region. The density of plant coverage and the distance from the edge of the fragment showed no clear relationship. This may b e due to the forest containing random levels of plant coverage throughout, or it could mean that the distance studied was not sufficient to see the differences between edge and interior habitat. In addition, the age and type of forest may have a bigger rol e in determining plant coverage than the distance from the edge. Secondary forest habitat has more plant coverage at the understory level compared to primary forest. In addition, younger forests have more plant coverage than older forests (Bradfer Lawrence et al., 2018). Age and type of habitat may influence the predation rates and location of where birds set their nests, but more research is needed to determine the exact relationship. Studying habitat fragmentation allows for a broader understanding of th e effects and consequences of humandisturbed environments. This study showed that larger conserved areas have less bird egg predation. This, along with the suspected invasive predat ors , support conservation efforts to focus on protecting larger, more connected forest areas. However, the edge effects are still not fully understood. Further research should continue investigating the impacts of edge effects from fragmentation, and how far into the forest they could affect other species. Also, not all edges have been found to be detrimental to native species, which further illustrates the importance in studying the specific impact fragmentation has on the entire ecosystem (Benitez Malvido and ArroyoRodriguez, 2008). In nearly all cases tropical rain forest fragmentation has led to a loss of local species, making it vital to understand the ecosystem ecology (Turner, 1996) . This information can be used to inform conservation efforts to help ma intain the rich biodiversity that Costa Rica has to offer. A CKNOWLEDGEMENTS I would like to thank Emilia Triana for being the best primary I could have asked for and helping me even when it was late and my sentences stop ped sense making. Also to Federico Chinchilla for being my chauffeur to La Calandria every day and always making me laugh. S pecial thanks to mi primo, Andr s Camacho for reminding me that it doesn’t have to be perfect . I would also like to thank the other instructors of the EAP progra m, Frank Joyce and Sof a Flores, for all their help and support figuring out this independent research project, even after changing my project idea many, many times. Big shout out to F lix Salazar for always hooking it up with the snacks. Thanks to all the other EAP students, especially Heather Lindsay for being my emotional rock throughout the pr oject and always finding the good in any situation. LITERATURE CITED Bakermans, M., Rodewald, A., and Vitz , A. (2012). Influence of forest structure on density and nest success of mature forest birds in managed landscapes. The Journal of Wildlife Management, 76(6), 12251234. https://doi.org/10.1002/jwmg.349 Belles Isles, J. C., and Picman , J. (1986). House Wren Nest Destroying Behavior. The Condor, 88, 190193. Benitez Malvido, J., and ArroyoRodriguez, V. (2008). Habitat fragmentation, edge effects and biological corridors in tropical ecosystems. In: Encyclopedia of Life Support Systems. EOLSS Publishers: Oxford. Web. Retrieved from

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Avian Nest Predation in Forest Fragments Gibbons 10 https://www.researchgate.net/publication/242075972_Habitat_fragmentation_edge_effect s_and_biological_corridors_in_tropical_ecosystems BradfordLawrence, T., Gardner, N., and Dent, D. H. (2018) Canopy bird a ssemblages are l ess i nfluenced by habitat a ge and i solation than understory bird a ssemblages in neotropical s econdary f orest. Ecology and Evolution. https://doi.org/10.1002/ece3.4086 Crick, H., Dudley, C., Evans, A., and Smith, K. (1994). Causes of nest failure among bunting in the UK. Bird Study, 41( 2), 8894. https://doi.org/10.1080/00063659409477203 Didham, R. K. (2010). Ecological c onsequences of habitat f ragmentation. Encyclopedia of Life Sciences. https://doi.org/10.1002/9780470015902.a0021904 Latif, Q., Heath, S., Rotenberry, J. (2012). How avian nest site selection responds to predation risk: testing an ‘adaptive peak hypothesis.’ Journal of Animal Ecology, 81, 127138. https:/ /doi.org/10.1111/j.13652656.2011.01895.x Massaro, M., Stanbury, M., and Briskie, J. (2012). Nest site selection by the endangered black robin increases vulnerability to predation by invasive bird. Animal Conservation, 16 (4 ) , 404411, https://doi.org/10.1111/acv.12007 Newmark, W. D., and Stanley, T. R. (2011). Habitat fragmentation reduces nest survival in an Afrotropical bird community in a biodiversity hotspot. Proceedings of the National Academy of Sciences of the United States of America, 108(28), 11488–11493. http://doi.org/10.1073/pnas.1104955108 Norton, D. A. (2002). Edge e ffects in a l owland t emperate New Zealand r ainforest. DOC Science Internal Series, 27. Department of Conservation, Wellington. pp. 33. Nour, N. Van Damme, R., Matthysen , E., and Dhondt, A. (1999). Forest birds in forest fragments: are fragmentation effects independent of season? Bird Study, 46(3) , 279288. https://doi.org/10.1080/00063659909461140 Primack, R. B. (2000). A Primer of Conservation Biology. Sunderland, MA: Sinauer Associates, Inc. Ribeiro, V. and Penido, G. (2015). Artificial nests predation in an AmazonCerrado transition. Neotropical Biology and Conservation, 10( 2), 103106. https://doi.org/10.4013/nbc.2015.102.06 So dhi, N., Barlow, J., Sekercioglu, C. and Robinson, S. (2011). Effects of Habitat Fragmentation on Tropical Birds. Conservation of Tropical Birds, 2744. https://doi.org/10.1002/9781444342611.ch2 Stiles, G. F. and Skutch, A. F. (1989). A G uide to the Birds of Costa Rica. Cornell Universi ty Press, Ithaca, New York: USA. Thompson, F. (2007). Factors affecting nest predation on forest songbirds in North America. International Journal of Avian Science, 149(2), 98109. https://doi.org/10.1111/j.1474 919X.2007.00697.x Turner, I. M. (1996). Sp ecies l oss in f ragments of t ropical r ain f orest: A r eview of the e vidence. Journal of Applied Ecology, 33(2). pp. 200209. DOI: 10.2307/2404743 Wehtje, W. (2003). The r ange e xpansion of the Great Tailed Grackle ( Quiscalus mexicanus) in North America since 1880. Journal of Biogeography, 30(10). pp. 15931607. https://doi.org/10.1046/j.13652699.2003.00970.x

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Avian Nest Predation in Forest Fragments Gibbons 11 APPENDIX A The maps of trails in La Calandria and Bajo Del Tigre in which nests were placed Each

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Avian Nest Predation in Forest Fragments Gibbons 12 APPENDIX B Density of Plant Coverage Rating Surrounding Artificial Nests Density Rating Description Example 1 Nest clearly visible, no plant coverage 2 Nest still visible, small degree of plant coverage on some sides

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Avian Nest Predation in Forest Fragments Gibbons 13 3 Reduced nest visibility, plant coverage from some sides 4 Nest still partially visible but difficult to spot, plant coverage for most sides

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Avian Nest Predation in Forest Fragments Gibbons 14 5 Nest not visible, plant coverage surrounding entire nest

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Avian Nest Predation in Forest Fragments Gibbons 15 APPENDIX C Examples of Visible Signs of Predation by Different Predators Predator Signs of Predation Large Bird (large, straight lines from picking egg up with beak, egg located outside of nest) Small Bird (small holes or beak marks from pecking egg, egg still located in nest) Squirrel (egg chewed, incisor marks visible)

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Avian Nest Predation in Forest Fragments Gibbons 16 APPENDIX D Condition of each artificial nest after a week Distance from edge represented by A, B, or C A= Edge B=Middle C= Interior BT = Located in Bajo Del Tigre C= Located in La Calandria Nest Condition of Nest 1A C Intact 2A C All eggs out of nest, two plasticine eggs collected with large beak marks, real egg missing 3A C All eggs out of nest, two plasticine eggs collected with large beak marks, real egg missing 4A C All eggs out of nest, two plasticine eggs collected with large beak marks, real egg missing 4A C Intact 1B C All eggs out of nest, two plasticine eggs collected with large beak marks, real egg missing 2B C Intact 3B C Intact 4B C All eggs out of nest, two plasticine eggs collected with large beak marks, real egg missing 5B C Intact 1C C All eggs in nest, two plasticine eggs collected with large beak marks, real egg intact 2C C Intact 3C C All eggs out of nest, one plasticine eg g collected with large beak marks, one plasticine egg missing, real egg missing 4C C All eggs out of nest, two plasticine eggs collected with large beak marks, real egg missing 5C C All eggs out of nest, two plasticine eggs collected with large beak marks, real egg missing 1A BT Intact 2A BT Intact 3A BT Intact 4A BT Intact 5A BT Intact 1B BT All eggs out of nest, two plasticine eggs collected with small beak and peck marks, real egg missing 2B BT Intact 3B BT All eggs still present in nest, real egg has hole pecked open but not consumed, plasticine eggs with small peck marks 4B BT All eggs out of nest, real egg found, two plasticine eggs missing

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Avian Nest Predation in Forest Fragments Gibbons 17 5B BT Two plasticine eggs collected from nest with small beak ma rks, real egg missing 1C BT Intact 2C BT Intact 3C BT Intact 4C BT Real egg missing, one plasticine egg in nest with small peck marks, other plasticine egg on ground with small beak marks 5C BT Real egg still in nest, one plasticine egg missing, other plasticine egg on ground collected with teeth marks

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Avian Nest Predation in Forest Fragments Gibbons 18 APPENDIX E Camera trap pictures of Rufousandwhite Wren approaching artificial nest in La Calandria


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Cras ut cursus ante, a fringilla nunc. Mauris lorem nunc, cursus sit amet enim ac, vehicula vestibulum mi. Mauris viverra nisl vel enim faucibus porta. Praesent sit amet ornare diam, non finibus nulla.

MLA

Cras efficitur magna et sapien varius, luctus ullamcorper dolor convallis. Orci varius natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Fusce sit amet justo ut erat laoreet congue sed a ante.

CHICAGO

Phasellus ornare in augue eu imperdiet. Donec malesuada sapien ante, at vehicula orci tempor molestie. Proin vitae urna elit. Pellentesque vitae nisi et diam euismod malesuada aliquet non erat.

WIKIPEDIA

Nunc fringilla dolor ut dictum placerat. Proin ac neque rutrum, consectetur ligula id, laoreet ligula. Nulla lorem massa, consectetur vitae consequat in, lobortis at dolor. Nunc sed leo odio.