Dabbling duck-habitat associations during winter in coastal South Carolina

During winters of 1985-88, we conducted fixed-wing aerial surveys of randomly selected 200- x 400-m plots along the coast of South Carolina to evaluate relative use of managed coastal impoundments and unimpounded tidal wetlands by 7 species of wintering dabbling ducks. In general, occurrence of dabbling ducks in managed coastal wetland impoundments was greater (P < 0.005) than expected, and occurrence in unman-aged tidal wetlands was less (P < 0.005) than expected for all species except American black ducks (Anas rubripes). Macrohabitat variables varied in frequency of association, direction and degree of influence, and yearly occurrence as correlates with dabbling duck abundance, but several consistent patterns emerged. Most species-abundance indices exhibited a frequent positive association with macrohabitat variables descriptive of managed wetland impoundments. We discuss possible explanations for observed dabbling duck-habitat associations and implications for maintaining intensively managed coastal impoundments to support regional waterfowl populations, particularly in highly altered coastal landscapes.