BREEDING BIOLOGY OF DARK-BELLIED BRENT GEESE BRANTA-BERNICLA-BERNICLAIN TAIMYR IN 1990 IN THE ABSENCE OF ARCTIC FOXES AND UNDER FAVORABLE WEATHER CONDITIONS

In combination with observations in spring staging and wintering groun ds in western Europe, a detailed etho-ecological study of nesting dark -bellied brent geese Branta b. bernicla in western Taimyr, Krasnoyarsk , Russia, was made in 1990. Most brent geese arrived on the breeding g rounds from 14-19 June and started nesting within a few days. In the s tudy area 264 nests of breeding brent geese were found, mainly on isla nds but also along small rivers on the mainland. The mean clutch size was 3.0 and 80% of the eggs hatched. Time budget studies showed that i ncubating females spent on average 138 minutes per 24 hours on feeding . Despite favourable weather conditions and a low density of arctic fo xes, only about one-third of the mature birds in the study area bred. In the autumn an intermediate breeding success of 20% juveniles was re corded in the wintering areas. This was probably due to the relatively poor condition in which the brent geese left their spring staging are as.