THE AUTUMN AND WINTER MORTALITY OF STARLINGS STURNUS VULGARIS, IN RELATION TO THEIR FOOD SUPPLY

Abstract

Summary. The food taken by Aberdeenshire Starlings during autumn and winter was investigated from stomach contents of samples shot regularly at roosts. The food available was known approximately. During severe weather feeding habits of the Starlings change so that they become almost entirely dependent on man. The gross weight and the fat‐deposits of the birds increased from autumn to mid‐winter and were not greatly affected by two snowy periods. The period of most acute food‐shortage for the Starling may be the early autumn, after the leatherjackets have disappeared and before oats become available. At this time the total weight and the fat‐weight of adults and juveniles are low and the birds are moulting. Density‐governed mortality, which contributes importantly to stability of the breeding‐population density, may occur at this time.