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
During the breeding season the species inhabits tropical and subtropical coasts, rocky offshore islands, coastal dykes, coastal dunes1, estuaries and harbours (Africa), as well as large inland fresh and alkaline lakes (Africa), rivers, salt-pans and marshes (Argentina). Outside of the breeding season the species remains along the shores of coastal habitats (e.g. rocky offshore islands, coastal dykes, coastal dunes and estuaries) but also frequents settlements, cattle pens and fishing harbours (in Africa).
Most populations of this species are sedentary, although inland breeders will disperse short distances to the coast in the non-breeding season. The species breeds colonially, from April-May (before the rains) in Africa, and from early-May in South America. It remains fairly gregarious outside of the breeding season, and is typically observed in pairs or small groups of 3-8 individuals, or feeding in large flocks in harbours and at refuse dumps.
Its diet consists predominantly of fish, as well as invertebrates (e.g. insects, molluscs and termites), the eggs of herons and cormorants, and dead fish and refuse obtained by scavenging.
This species has a large range, with an estimated global Extent of Occurrence of 1,000,000-10,000,000 km². It has a large global population estimated to be 240,000-440,000 individuals (Wetlands International 2002). Global population trends have not been quantified, but the species is not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e. declining more than 30% in ten years or three generations). For these reasons, the species is evaluated as Least Concern. [conservation status from birdlife.org]
This locally abundant gull breeds in large colonies in reedbeds and marshes, and lays two or three eggs in a nest that can be on the ground or floating. Like most gulls, it is highly gregarious in winter, both when feeding or 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.
Many populations are permanent residents or disperse short distances, with many inland breeders moving to coast. Birds from Natal move up to 2000 km N along Atlantic or Indian Ocean coasts. Dispersal apparent along coasts of W Africa and Argentina. In Peru, occurs as far S as Mollendo between Jul and Sept. Vagrants recorded N to Panama, and to Spain and N Red Sea.
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- spanwidth max.: 45 cm
- size min.: 42 cm
- size max.: 43 cm
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- Conservation Status