National J. A. Jurgens, Esq. 505 Wekiva Springs Road Suite 800 Longwood, FL 32779 Dear Jay: Audubon Society Ordway-Whittell Kissimmee Prairie Sanctuary 17350 N.W. 203rd Ave. Okeechobee, FL 34972 (941) 467-8497 May 22, 1998 This correspondence is in response to your question about the wading bird rookeries on our Sanctuary, particularly in relation to proposed activities on the 101 Ranch south of our Sanctuary. I will first describe our rookeries, with emphasis on how wetland impacts on 101 Ranch can affect these birds. I also list other birds that use our Sanctuary and the 101 Ranch. One rookery is in Wet Rock Marsh that averages 200 nests. A typical nesting composition is: 50% Cattle Egrets, 10% Great Blue Herons, 10% Great Egrets, 10% Little Blue Herons, 10% Snowy Egrets, and 10% . Tricolored Herons. Total number of nests and percents of each species vary from year to year, as is common for wading bird nesting sights in Florida (Smith and Collopy 1995). The last three birds are listed by the Florida Game and Fresh Water Fish Commission as "species of special concern." Another rookery is in a willowhead in Section 29. This rookery is predominantly small waders and has about 150 nests with Cattle Egrets occupying half and Tricolored, Snowys, and Little Blue Herons making up the other half. This rookery has Black crowned Night-Herons in it regularly, but I have not verified a nest yet. The third major rookery is in Shinn Hammock Marsh in Section 3. This rookery occupies a Gum Head and has mostly large waders and Anhingas. There typically will be about 15 nests each of Great Blue Herons, Great Egrets and Anhingas. I have found Anhingas nesting in other parts of the Sanctuary in small groups of 5-10 birds and am not sure how many locations are used in a year. Another notable rookery is on the Kissimmee Prairie State Preserve in Sevenmile Slough, about a mile west of our border. I have flown over this rookery a couple times and seen perhaps 300 birds in it, but I am uncertain what the species composition is, or the exact number of birds that regularly use it.
Healthy wetlands within a short distance of the nest are essential to reproductive success. The average foraging flight distance for the Great Egret in four studies in south Florida (Frederick and Collopy 1988, Bancroft et al. 1990, Frederick 1993, Smith 1995) was 3 miles (maximum 20 miles). Average foraging flight for nesting Snowy Egrets in 3 south Florida studies was 5.6 miles (maximum 39 miles)(Frederick and Collopy 1988, Bancroft et al. 1990, and Smith 1995). Two studies on south Florida Tricolored Herons yielded average foraging flights of3.8 miles (maximum 16 miles)(Bancroft et al. 1990, Smith 1995). Clearly, all wetlands on the 101 Ranch are in the foraging radius of these birds. Wading birds colonies in the Everglades have declined about 90% even though only 50% of the wetlands have been drained. The reason for the larger decline in birds than wetlands is the remaining wetlands are not functioning correctly. Common problems include a shortened hydroperiod that prevents many of the aquatic prey from forming large enough populations to support birds, and altered timing of wetland flooding, which also disrupts life patterns of these prey animals. Our Sanctuary is not large enough to meet all the needs of the wading bird rookeries. For example, last year, the spring was dry and even though the Sanctuary had water in the wetlands, wading birds did not nest. They apparently did not detect enough wetland habitat in the region to trigger a nesting response. This is a common phenomenon in the Everglades and even on Lake Okeechobee (Bancroft et al. 1990, Frederick and Collopy 1988, Smith and Collopy 1995). It is critical to the Sanctuary wading bird rookeries that wetlands in the area, and particularly on the adjacent 101 Ranch, are not drained or damaged. Other Federally or State listed birds that frequent the Sanctuary include: Bald Eagles-uncommon; Osprey-uncommon; Swallow-tailed Kite-uncommon, perhaps nesting; Snail Kite-uncommon; Roseate Spoonbill-rare; Lirnpkin-common, nesting has been recorded but not consistently; White Ibis--common, no nesting record to my knowledge; Florida Sandhill Crane-common, nesting; Wood Stork-fairly common, no nesting record to my knowledge; Audubon's Crested Caracara-common, no nesting record to my knowledge; Burrowing Owl-uncommon, have nested. Eight of these are wetland dependent birds and like the rookery birds, need large areas of suitable habitat to persist. The Burrowing Owls are upland animals, and like our Grasshopper Sparrows, have suffered due to the flooding we have experienced ( actually, the Burrowing Owls are gone, but I think they will return once we restore a proper hydrology). Damage to wetlands on surrounding ranches damages our bird populations. Sincerely, Paul N. Gray, Ph.D, Manager
Literature Cited Bancroft, G. T., S. D. Jewell, and A. M. Strong. 1990. Foraging and nesting ecology of herons in the lower Everglades relative to water conditions. Final Report. South FL Water Manage. Dist., West Palm Beach, FL. Frederick, P. C. 1993. Wading bird nesting success studies in the Water conservation Areas of the Everglades, 1992. Final Report. South FL Water Manage. Dist., West Palm Beach, FL. Frederick, P.C., and M. W. Collopy. 1988. Reproductive ecology of wading birds in relation to water conditions in the Florida Everglades. FL Coop. Fish and WildL Res. Unit. And Univ. FL School of Forest Res. And Cons. Technical Report 30. Smith, J.P. 1995. Foraging flights and habitat use of nesting wading birds (Ciconiiformes) at Lake Okeechobee, Florida. Colonial Waterbirds 18:139-158. Smith, J.P., and M. W. Collopy. 1995. Colony turnover, nest success and productivity, and causes of nest failure among wading birds (Ciconiiformes) at Lake Okeechobee, Florida (1989-1992). Arch. HydrobioL Spec. Issues Advanc. LimnoL 45:287-316. Smith, J.P., J. R. Richardson, and M. W. Collopy. 1995. Foraging habitat selection among wading birds ( Ciconiiformes) at Lake Okeechobee, Florida, in relation to hydrology and vegetative cover. Arch. Hydrobiol. Spec. Issues Advanc. Limnol. 45:247285.