The grey-headed gull is slightly larger than the black-headed gull at 42 cm length. The summer adult has a pale grey head, a grey body, darker in tone than the black-headed, and red bill and legs. The black tips to the primary wing feathers have conspicuous white `mirrors`. The underwing is dark grey with black wingtips. The grey hood is lost in winter, leaving just dark streaks. Sexes are similar. The South American race is slightly larger and paler-backed than the African subspecies. This gull takes two years to reach maturity. First year birds have a black terminal tail band, and more dark areas in the wings. In flight, the wings are broader and held flatter than those of black-headed gull. Like most gulls, it is highly gregarious in winter, both when feeding and in evening roosts. Although it is predominantly coastal or estuarine, it is not a pelagic species, and is rarely seen at sea far from land. Flocks numbering hundreds or thousands of these gulls can form when the feeding conditions are appropriate.
Habitat and Distribution
It breeds patchily in Africa south of the Sahara and South America.
This locally abundant gull breeds in large colonies in reedbeds and marshes, and lays two or three eggs in a nest, which can be on the ground or floating.
Calls and Songs
This is a noisy species, especially at colonies. The call is a raucous crow-like caw, caw.