| Summary: | Data on tundra swans (Cygnus columbianus columbianus) were obtained on the northern Alaska Peninsula from 1983 to 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 ten days. The highest densities of potential breeders (0.3-0.9 swans/sq km) occurred along the lowland coast and in broad drainage basins. Estimates of the breeding population ranged from 4000 to 4600 swans. Brood sizes in August ranged from 2.7±0.3 S.E to 3.3±0.5 young. In summer, 51-66% of the adults and subadults were observed as potential breeders, and the remainder were in nonbreeding flocks. Between 31 and 40% of the 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.Key words: aerial survey, Alaska Peninsula, Bristol Bay, Alaska, phenology, Cygnus columbianus columbianus, migration, productivity, tundra swan Mots clés: relevé aérien, péninsule de l’Alaska, Bristol Bay, Alaska, phénologie, Cygnus columbianus columbianus, migration, productivité, cygne siffleur
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