Seasonal changes in the feeding ecology of guillemots (Uria aalge) off north and east Scotland

Stomach contents were examined from 750 guillemots collected at several sites in the northern North Sea. The dietary composition was compared between months and between localities in order to assess seasonal and geographical trends in feeding strategy.From March to August sandeels dominated the diet, but in September a changeover period occurred when clupeid and gadoid remains became increasingly frequent in the stomach contents. This situation persisted over the winter period, but the importance of the two fish families varied with area, clupeids being more important in more southerly samples and gadoids in the north. Dietary data were considered in relation to available fisheries information and to known guillemot distribution patterns.