Yellow-billed Loon, Gavia adamsii, breeding chronology and reproductive success in arctic Alaska

Abstract

The breeding chronology of Yellow-billed Loons (Gavia adamsii) was studies in 1983 and 1984 on the Colville River delta in arctic Alaska. Yellow-billed Loons arrived on the delta within four days after open water became available in river channels in late May. They stayed on rivers until open water leads formed along lakeshores. The first nests were found on 15 and 16 June, 1983, and 1984, respectively, but in 1984 the peak of nest initiation was delayed about one week because of late ice melt on the lakes. The first young hatched 11 July both years. Incubation length was 27 to 28 days. At least one egg hatched from 16 of 17 nests monitored both years. Productiviy was 1.29 chicks/breeding pair in 1983 and 0.94 chicks/breeding pair in 1984.