Gulls associating with flocks of Brent Geese Branta bernicla on farmland

Abstract

Black-headed Culls (median n 15) and Common Gulls (3.5) associated with Brent Geese (median flock size 725) grazing winter wheat and grassland in winter and fed on invertebrates disturbed by the geese. The number of gulls was larger in bigger flocks of geese. On two days, more gulls were present in the late afternoon compared with the rest of the day. Most (77%) of the gulls fed while walking among the geese whilst others searched the ground during a slow flight over the flock; their diet on winter wheat was worms, beetles, fly larvae and spiders.