THE FOOD AND FEEDING HABITS OF TUFTED DUCK AYTHYA FULIGULA

The food and feeding habits of Tufted Duck Aythya fuligula are described, based on field observations and on the analyses of the stomach contents of 95 birds, all but one of them having fed inland; 57 were collected from a gravel pit near London, 28 from Northern Ireland and 9 from a number of English inland waters, in the shooting seasons 1959-60 and 1960-61.
The London birds in both seasons had fed primarily on molluscs, mainly Dreissena polymorpha. The Northern Ireland birds, where D. polymorpha does not occur, had a more variable diet, again mainly molluscs, but with some crustaceans, insects and plant seeds. The English birds had a similarly variable diet with the emphasis on crustaceans ( Asellus spp.) and with some molluscs, insects and plant seeds. Brief information is given on the food of young birds.
It is suggested that the spread of D. polymorpha may be one of the factors explaining the recent spread of the Tufted Duck in certain areas. It appears that where one particular food such as D. polymorpha is not plentiful a more variable diet is taken, though molluscs always figure prominently. The type of food taken depends on the type of habitat used, the availability and size of the food items and on the methods of feeding.