Biological notes on the emperor goose in north-east Siberia

Abstract

Observations were made in 1970 on Emperor Geese Anser canagicus on the northern coast of the Chukotsky Peninsula. The first geese were seen on 7th June. Nesting began immediately on arrival on the narrow coastal strip in the wet moss-sedge tundra rich in freshwater ponds. The breeding density was three pairs on 40 sq. km. Two nests (two and nine eggs) are described. Nest bedding of grass, goose's feathers and down was added during egg-laying and incubation, but was never so thick and soft as that of White-fronted Anser a. albifrons or Brant Geese Branta bernicla orientalis. Eggs were laid from 6th to 18th June, incubation time being 25 days. During incubation the pair bond is maintained, although the male may fly quite far for feeding and join other birds for a while. Hatching took place on 11th-13th July; the weather was very severe at the time, and mortality was high (eight eggs and young of eleven). It is though that poor resistance of goslings to cold and low heat-insulation properties of nests limit further extension of the species to the north. Breeding geese feed in the nesting habitat on the sedge Carex stans. In the second half of June non-breeding Emperors began their moult movements. Large concentrations of non-breeders (up to 2,000) were found near Ukouge lagoon but remained there only up to the first ten days of July. We believe that a sizable part of the Asiatic population gathered there., Flocks of non-breeders kept to the wet brackish grassy tundra around the lagoon consisting of Dupontia psilosantha, Carex subspathacea, Cochlearia arctica and Stellaria humifusa. Geese are shoots and terminal parts of the young leaves of D. psilosantha and C. subspathacea. This food is unlimited. Moulting flocks leave dozens of kilograms of droppings per hectare; thus, they return to the soil considerable quantities of nitrogen, P2O5 and K2O. A massive development of the caecum is noted. The behavior when breeding and in moulting flocks, and the calls, are described.