Winter Abundance of the American Oystercatcher in South Carolina

Abstract

Abstract South Carolina winters a large proportion (over 1/3) of the eastern race of the American Oystercatcher (Haematopus palliatus), a declining species. During December of 1999-2002 ground surveys were conducted to provide baseline data on the abundance, age class partitioning and distribution of wintering American Oystercatchers in South Carolina. The number of oystercatchers in South Carolina was stable during this study (3,536, 95% CI: 3,030, 4,042). A single comprehensive survey can estimate the number of oystercatchers with enough precision to detect changes in the population of 13% and greater, but location of flocks and the range of tidal heights needed to concentrate flocks must be known prior to conducting the survey. About 89% of the birds in 2002 roosted on washed shell rakes and 9% had immature bill coloration. Winter surveys of the proportion of immature oystercatchers may provide an index of regional reproductive success, an important parameter for conservation plans. Because South Carol...