Breeding success of White-fronted Geese from the Nenets National Area

Abstract

The breeding success of White-fronted Geese has been inferred from the age composition of flocks wintering at Slimbridge, Gloucestershire, since 1947. These Whitefronts breed in the north east of European Russia. Annual variations in brood-size (average 3.24) have been comparatively slight, though there were unusual numbers of small broods in 1950 and 1958 and of large broods in 1951 and 1956. The proportion of first-winter geese has varied widely about a mean of 33.3%. The fluctuations seem to have reflected changes in output rather than in adult mortality. Attempts to relate production to the limited weather data from the breeding areas by means of correlation methods suggest that wet weather in July has markedly reduced production. Snow in late May and early June has been less important, while low temperatures without snow have had no perceptible effect. Marked geese breeding for the first time, at nearly three years old, have had smaller families than parents four to six years old. So have those more than seven years old.