Symposium Participants: Stephen Brown
Population size, winter distribution, and habitat associations of the eastern subspecies of American Oystercatchers (Haematopus palliatus palliatus)
Stephen Brown (1), Shiloh Schulte (1), Brian Harrington (1), Brad Winn (2), Jonathan Bart (3), and Marshall Howe (4)
1. Manomet Center for Conservation Sciences, P.O. Box 1770 , Manomet , MA , 02345 , 508-224-6521, sbrown@manomet.org, sschulte@manomet.org, bharr@manomet.org
2. Georgia Department of Natural Resources, One Conservation Way , Brunswick GA , 31520 , 912-262-3128, brad_winn@dnr.state.ga.us
3. USGS Forest and Rangeland Ecological Science Center , Snake River Field Station, 970 Lusk St. , Boise , ID 83706 , (208) 426-5216, jbart@eagle.boisestate.edu
4. Patuxent Wildlife Research Center, 12100 Beech Forest Rd., #4038 Laurel, MD 20708-4038, (301) 497-5858, marshall_howe@usgs.gov
Conservation of the eastern subspecies of the American Oystercatcher (Haematopus palliatus palliatus) is a high priority in the U.S. Shorebird Conservation Plan, but previous population estimates were unreliable, information on distribution and habitat associations during winter was incomplete, and methods for long-term monitoring had not been developed. We completed the aerial survey proposed in the Shorebird Plan to determine population size, winter distribution, and habitat associations (http://www.shorebirdworld.org/template.php?g=9&c=19). Coastal aerial surveys were conducted from New Jersey to Texas during November 2002 to February 2003 ). This area comprises the wintering range for the entire United States population of the eastern American Oystercatcher. The study area included all sites with suitable habitat for the subspecies and was partitioned into three survey strata: known roost sites, high-use habitat, and intercoastal tidal habitat. Known roost sites were determined from extensive consultation with biologists and local experts in each state. High-use habitat included sand islands, sand spits at inlets, shell rakes, and oyster reefs. Partner organizations conducted ground counts in most states. We used high resolution still photography to determine detection rates within estimates of the size of particular flocks, and ground counts to determine detection rates of flocks. We estimate the population of American Oystercatchers to be 10,971 +/- 298. Most birds used roost sites on shell rakes (40%) and sand islands (21%). Aerial surveys are an important technique that, when combined with ground counts in high density areas, can determine population size and trend for this subspecies, and possibly for other coastal shorebirds and waterbirds.
