Greylag Geese in Britain in winter

Abstract

Personal investigations in 1957 and 1958 are combined with data contributed by more than 130 observers to illustrate the present distribution of the Greylag in the British Isles in winter. Most of the geese are concentrated in the southern half of Scotland, between 54 40' N and 56 40' N. Some 120 localities are known to have been frequented by flocks of Greylags during the winters 1955-58. Only 16 places, all in Scotland, harbour more than 1,000 Greylags for any considerable period. No census has been achieved, but the records suggest that the population is likely to have numbered between 17,000 and 23,000 in late November 1957 and again in late November 1958. Data from earlier years, and from other times during the winter, are less complete. The numbers in the autumn of 1956 were probably similar to those in 1957 and 1958, but there may have been fewer in 1955. The impression of scarcity in the winter of 1955-56 is supported by counts in a sample of major localities, covering the years 1952-58. This sample also showed a comparatively massive peak in 1953-54 followed by a slump in 1954-55. Maps of recoveries of ringed Greylags are used in conjunction with data on numbers to show the general pattern of winter movements. The resident Scottish population, which is very probably less than 5% of the autumn total, seems to be nearly sedentary, remaining in the Outer Hebrides and the north and west of Scotland. The Iceland-breeding geese, which comprise almost the entire bulk of winter immigrants, enter Scotland during October and November and leave again from February to April. Much of the movement in the intervening months is of a local character, shifting between roosts five to fifty miles apart, but there is a tendency for numbers to decrease in the north and increase in the south-west of Scotland from November through February. In Ireland most are seen in December and January. The Icelandic Greylag population seems to be in a comparatively steady state at present, after increasing greatly during the last thirty years, and changes in its choice of wintering places gives no cause for other than local concern. The British-breeding population, which has decreased seriously during this century, needs to be considered separately.