Kelp gull

The kelp gull (''Larus dominicanus''), also known as the Dominican gull, is a gull that breeds on coasts and islands through much of the Southern Hemisphere. The nominate ''L. d. dominicanus'' is the subspecies found around South America, parts of Australia (where it overlaps with the Pacific gull), and New Zealand (where it is known as the black-backed gull, the southern black-backed gull, mollyhawk – particularly the juveniles, or by its Māori name ''karoro''). ''L. d. vetula'' (known as the Cape gull) is a subspecies occurring around Southern Africa.

The specific name comes from the Dominican Order of friars, who wear black and white habits.

Description

The kelp gull superficially resembles two gulls from further north in the Atlantic Ocean, the lesser black-backed gull and the great black-backed gull, and is intermediate in size between these two species. This species ranges from in total length, from in wingspan and from in weight. Adult males and females weigh on average and respectively. Among standard measurements, the wing chord is , the bill is and the tarsus is .''Gulls: Of North America, Europe, and Asia'' by Klaus Malling Olsen & Hans Larsson. Princeton University Press (2004). .Harrison, Peter, ''Seabirds: An Identification Guide''. Houghton Mifflin Harcourt (1991), ''CRC Handbook of Avian Body Masses'' by John B. Dunning Jr. (Editor). CRC Press (1992), . The adult kelp gull has black upper parts and wings. The head, underparts, tail, and the small "mirrors" at the wing tips are white. The bill is yellow with a red spot, and the legs are greenish-yellow (brighter and yellower when breeding, duller and greener when not breeding). The call is a strident ''ki-och''. Juveniles have dull legs, a black bill, a dark band in the tail, and an overall grey-brown plumage densely edged whitish, but they rapidly get a pale base to the bill and largely white head and underparts. They take three or four years to reach maturity.

Subspecies

There are five subspecies of kelp gull. The African subspecies ''L. d. vetula'' is sometimes split as the Cape gull, ''L. vetula''. It has a more angular head and a smaller shorter bill. The adult has a dark eye, whereas the nominate kelp gull usually has a pale eye. Young Cape gulls have almost identical plumage to similarly aged kelp gulls.

The kelp gull is a rare vagrant to the United States, with the first record in 1989 on Chandeleur Islands in Louisiana. They have interbred with American herring gull on these islands, leading to intermediate birds that may backcross to one another. After Hurricane Katrina in 2005, breeding populations of the two species and their hybrids were displaced from the island, though putative hybrids have been reported elsewhere and may be the result of other offshore colonies.

Behaviour

Kelp gulls are omnivores like most ''Larus'' gulls, and they will scavenge as well as seek suitable small prey. They gather on landfills and a sharp increase in population is therefore considered as an indicator for a degraded environment. Kelp gulls have been observed feeding on living right whales since at least 1996.Increased harassment of Right Whales (''Eubalaena australis'') by Kelp Gulls (''Larus dominicanus'') at Península Valdés, Argentina
Rowntree, V.J., P. MacGuiness, K. Marshall, R. Payne, J. Seger, and M. Sironi, 1998. ''Marine Mammal Science''. 14(1): 99 – 115. The kelp gull uses its powerful beak to peck down centimetres into the skin and blubber, often leaving the whales with large open sores, some of which have been observed to be half a meter in diameter. This predatory behavior has been documented in Argentinian waters.Gulls' vicious attacks on whales
. BBC News, June 24, 2009. At rocky sites along the Southern African coast, such as at Boulders Beach in Cape Town, kelp gulls (''Larus dominicanus vetula'') can be seen picking up shellfish and repeatedly flying up several meters and dropping them onto the rocks below in order to break them open. They have also been reported pecking the eyes out of seal pups on the coast of Namibia before attacking the blind seals in a group.

The nest is a shallow depression on the ground lined with vegetation and feathers. The female usually lays 2 or 3 eggs. Both parents feed the young birds.

Gallery

File:Kelp_Gull_-_Gaviota_Dominicana_-_Larus_Dominicanus.jpg, At Concón, Chile

File:Larus dominicanus -New Zealand-28 Dec2009.jpg, Adult and two chicks in New Zealand
File:Larus dominicanus2.jpg, Juvenile in New Zealand
File:Kelp gull in flight in New Brighton, Christchurch, New Zealand.jpg, Kelp gull in flight
File:A Kelp Gull in Bahia Inglesa Chile Sep 2009.jpg, Subspecies ''L. d. dominicanus'' stealing a meal of shellfish from blackish oystercatchers in Bahía Inglesa, Chile

Cape gull (''Larus dominicanus vetula'' or ''Larus vetula'')

File:Kelp Gull, South Africa.JPG, Cape gull (''L. d. vetula''), Boulders Beach, South Africa
File:Cape Gull RWD.jpg, Hout Bay, South Africa
File:Gull, Cape RWD3.jpg, Hout Bay, South Africa
File:Cape gulls, South Africa.jpg, Cape gulls searching for food in South Africa

The Cape gull differs from other forms of kelp gulls by its darker iris and larger body and bill size. The Southern African population is estimated to include 11,000 breeding pairs, and is expanding.

References

* 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




Specimens
of Larus dominicanus in the collection of Museum of New Zealand Te Papa Tongarewa

{{Taxonbar, from=Q1127687

kelp gull
Birds of Antarctica
Birds of Patagonia
Birds of Madagascar
Birds of Southern Africa
Birds of the Southern Ocean
Birds of subantarctic islands
kelp gull
Fauna of Macquarie Island