Distribution, abundance, population structure and productivity of tundra swans in Bristol Bay, Alaska

Abstract

Cygnus columbianus columbianus were studied on the N Alaska Peninsula from 1983-1987. Phenology was advanced 2-4 weeks of swan nesting areas in the Subarctic and Arctic, but a late spring retarded nesting by at least 10 days. Highest densities of potential breeders (0.3-0.9 swans.km-2) occurred along the lowland coast and in broad drainage basins. Estimates of the breeding population ranged from 4000-4600 swans. Brood sizes in August ranged from 2.7±0.3 SE to 3.3±0.5 young. In summer, 51-66% of the adults and subadults were potential breeders; the remainder were in nonbreeding flocks. Between 31-40% of observed pairs had nests or young. The population and production on the Alaska Peninsula may be less affected by weather than populations at higher latitudes. -from Author