Hartlaub's gull (''Chroicocephalus hartlaubii'') is a small

gull Gulls, or colloquially seagulls, are seabirds of the subfamily Larinae. They are most closely related to terns and skimmers, distantly related to auks, and even more distantly related to waders. Until the 21st century, most gulls were placed ...

in the genus ''

Chroicocephalus ''Chroicocephalus'' is a genus of medium to relatively small gulls which were included in the genus ''Larus'' until genetic evidence published in 2005 showed that ''Larus'' as then constituted was paraphyly, paraphyletic. Ten species are currentl ...

''. It was formerly (as with other related gulls) placed in the genus ''

Larus ''Larus'' is a large genus of gulls with worldwide distribution (by far the greatest species diversity is in the Northern Hemisphere). Many of its species are abundant and well-known birds in their ranges. Until about 2005–2007, most gulls ...

'' until genetic research demonstrated that the old broad view of that genus was

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

. In the past it had sometimes been treated as a subspecies of the Australasian

silver gull The silver gull (''Chroicocephalus novaehollandiae'') is a gull in Oceania. It is the most common gull of Australia. It has been found throughout the continent, but particularly at or near coastal areas. It is smaller than the Pacific gull (''L ...

(''C. novaehollandiae''), but is now treated as a separate species; current genetic evidence suggests its closest relative is not the silver gull but the African and South American

grey-headed gull The grey-headed gull (''Chroicocephalus cirrocephalus''), also known as the grey-hooded gull, is a small species of gull which breeds patchily in South America and Africa south of the Sahara. It is not truly migratory, but is dispersive, becomin ...

(''C. cirrocephalus''), and in particular the African subspecies of it ''C. c. poiocephalus'' (with the possibility that ''C. cirrocephalus'' is paraphyletic with respect to ''C. hartlaubii'': Černý & Natale 2022, Fig. 6). The species' name commemorates the German physician and zoologist,

Gustav Hartlaub Karel Johan Gustav Hartlaub (8 November 1814 – 29 November 1900) was a German physician and ornithologist. Hartlaub was born in Bremen, and studied at Bonn and Berlin before graduating in medicine at Göttingen. In 1840, he began to study and ...

. In the past, it was also sometimes known as "king gull".

Description

Hartlaub's gull is 37–39 cm in length, with a wingspan of 89–92 cm and a weight of 235–340 g. It is a mainly white gull with a grey back and upperwings, black wingtips with conspicuous white "mirrors", and a dark red bill and legs. When breeding it has a very faint lavender grey hood, but otherwise has a plain white head. The sexes are similar. This species differs from the slightly larger

in its thinner, darker bill, deeper red legs, paler, plainer head, and dark eyes. It takes two years to reach maturity. Juvenile birds have a brown band across the wings. They differ from same-age grey-headed gulls in that they lack a black terminal tail band, less dark areas in the wings, darker legs, and a white head.

Distribution and habitat

The gull is a

non-migratory Bird migration is a seasonal movement of birds between breeding and wintering grounds that occurs twice a year. It is typically from north to south or from south to north. Animal migration, Migration is inherently risky, due to predation and ...

breeding resident endemic to the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

coastline of

South Africa South Africa, officially the Republic of South Africa (RSA), is the Southern Africa, southernmost country in Africa. Its Provinces of South Africa, nine provinces are bounded to the south by of coastline that stretches along the Atlantic O ...

and

Namibia Namibia, officially the Republic of Namibia, is a country on the west coast of Southern Africa. Its borders include the Atlantic Ocean to the west, Angola and Zambia to the north, Botswana to the east and South Africa to the south; in the no ...

. Although it is predominantly coastal or estuarine, it is not a pelagic species, and is rarely seen at sea far from land. About one half of the total population, currently estimated at 30,000 birds, lives within the Greater

Cape Town Cape Town is the legislature, legislative capital city, capital of South Africa. It is the country's oldest city and the seat of the Parliament of South Africa. Cape Town is the country's List of municipalities in South Africa, second-largest ...

area. It has accommodated well to humans, and can become very tame around habitations. Although it is a relatively rare species, about the tenth rarest of the world's 50 or so gull species, it is common in its range and is widely regarded in Cape Town as a nuisance, fouling buildings and bathing in urban ponds. It has, at times, been a hazard to aircraft near airports.

Behaviour

Like most gulls, Hartlaub's is highly gregarious in winter, both when feeding or in evening roosts. This is a noisy species, especially at colonies. The call is a raucous

crow A crow is a bird of the genus ''Corvus'', or more broadly, a synonym for all of ''Corvus''. The word "crow" is used as part of the common name of many species. The related term "raven" is not linked scientifically to any certain trait but is rathe ...

-like ''kaaarrh''. This species is frequently the subject of complaints about the noise it makes in urban areas.

Breeding

Hartlaub's gull breeds in large colonies, and the main traditional breeding colony for the Cape Town area is on

Robben Island Robben Island () is an island in Table Bay, 6.9 kilometres (4.3 mi) west of the coast of Bloubergstrand, north of Cape Town, South Africa. It takes its name from the Dutch language, Dutch word for seals (''robben''), hence the Dutch/Afrika ...

. The adults fly to the mainland to find food for their chicks, a round trip of about 24 km. Although most breed in large colonies on islands, some have started nesting on coastal buildings.

Feeding

The species is omnivorous like most ''Larus'' gulls, and they will scavenge at tips and feed on scraps as well as seeking suitable small prey, often by wading in shallow water.

References

* Harrison, ''Seabirds'' * Ian Sinclair, Phil Hockey and Warwick Tarboton, ''SASOL Birds of Southern Africa'' (Struik 2002)

External links

Species text in The Atlas of Southern African Birds
{{Taxonbar, from=Q1274356

Hartlaub's gull Hartlaub's gull (''Chroicocephalus hartlaubii'') is a small gull in the genus ''Chroicocephalus''. It was formerly (as with other related gulls) placed in the genus ''Larus'' until genetic research demonstrated that the old broad view of that gen ...

Birds of Southern Africa