Long-tailed Duck, Clangula hyemalis, Eider, Somateria spp., and Scoter, Melanitta spp., Distributions in Central Alaska Beaufort Sea Lagoons, 1999-2002

During July and August 1999–2002, distributions of Long-tailed Ducks (Clangula hyemalis), eiders (Somateria spp.) and scoters (Melanitta spp.) were documented in three barrier island-lagoon systems in the central Alaska Beaufort Sea. Concentration areas for each species were determined during 16 aerial surveys. Kernel density procedures were used to delineate 75% and 50% “activity” or concentration areas for all three species. Long-tailed Ducks were 13 times more numerous than eiders and 38 times more numerous than scoters. The Long-tailed Duck 75% activity area encompassed all three lagoon systems and was three times as large as the eider activity area and one-third larger than the scoter activity area. Eider activity areas were located only in the eastern lagoon, and scoter activity areas were located only in the western lagoon. Density contours showed patterns of repeated habitat use for sea ducks over the four years of sampling and improve our understanding of sea duck habitat use within Beaufort Sea barrier island-lagoon habitats