The 25,000 km of shoreline in southeast Alaska was surveyed for waterbirds by fixed-wing aircraft in summer and winter during the period 1997 to 2002. A ground/boat survey double sampled 20% of the summer habitat and 5% of the winter habitat to adjust and enhance the air survey. The most abundant species during the summer surveys, with visibility correction factors applied, were gulls (Larus spp.; 306,200, CV = 0.004), scoters (Melanitta spp.; 185,700, CV = 0.004), and Harlequin Duck (Histrionicus histrionicus; 34,640, CV = 0.03). The most abundant species observed during the winter surveys were goldeneyes (Bucephala islandica and B. clangula; 121,920, CV = 0.01), gulls (105,000, CV = 0.01), Mallard (Anas platyrhynchos; 98,090, CV = 0.01), scoters (77,300, CV = 0.01), Harlequin Duck (54,540, CV = 0.02), Bufflehead (Bucephala albeola; 46,840, CV = 0.03), and mergansers (Mergus spp.; 39,940, CV = 0.02). The variance estimates did not include uncertainty about the visibility correction factors. We observed 2.4 times as many scoters in summer as in winter and surmise they were sub-adults, failed breeders, and adult males which had deserted females on the breeding grounds. Complete shoreline coverage provided precise estimates for the abundant species. Meaningful population values could be generated for very specific subunits selected after completion of the survey because all shoreline was covered and all observations were tied to a geographic location.
Full citation: Hodges, John I., Deborah J. Groves, and Bruce P. Conant. 2008. Distribution and abundance of waterbirds near shore in southeast Alaska, 1997-2002. Northwestern Naturalist 89:85-96.
