Olrog's gull | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Charadriiformes |
Family: | Laridae |
Genus: | Larus |
Species: | L. atlanticus |
Binomial name | |
Larus atlanticus Olrog, 1958 | |
Olrog's gull (Larus atlanticus) is a species of gull found along the Atlantic coast of southern Brazil, Uruguay, and northern Argentina. It was formerly considered a subspecies of the very similar L. belcheri . It is a large gull with a black back and wings, white head and underparts, a black band in the otherwise white tail, and a yellow bill with a red and black tip. Nonbreeding adults have a blackish head and a white eye ring. The species is named after Swedish-Argentine biologist Claes C. Olrog. [2] [3] It has a rather restricted breeding range and is threatened by habitat loss, and the IUCN has rated it as being "near threatened".
Olrog's gull is a large gull with a white head, neck, rump, breast, and belly. The back and wings are black except for a white trailing edge to the wings. The tail is white with a broad black band at the back. The beak is yellow with a black band and red tip. The eyes are brown with a red orbital ring and the legs and feet are dull yellow. The length of this gull is 50 to 60 cm (20 to 24 in) and it has a wingspan of 130 to 140 cm (51 to 55 in). Males are a little larger than females. Juveniles have black heads and brownish plumage. [4]
Olrog's gull is native to the Atlantic coast of Argentina, Uruguay, and southern Brazil. It breeds at a very limited number of colonies between 38.49° and 45.11°S, about two-thirds of which are in the estuary of the Bahia Blanca River. It nests on the ground just above high-water mark, on low islands and islets. At other times, it is to be seen on rocky coasts, harbours, beaches, coastal lagoons, brackish water, and estuaries. [5]
During the breeding season, Olrog's gull feeds largely on crabs, which are picked up from the exposed shore or the seabed while walking or swimming, or dipping under the surface of shallow water. This particular diet gives the gull its name in its native range: gaviota cangrejera, or crab-eater gull.
At other times of year, it supplements its crab diet with bivalve molluscs and polychaete worms. Other prey items include insects, gastropod molluscs, fish, and fish waste, and the birds sometimes visit sewage outlets and refuse dumps. [6]
Breeding starts in September and October. Olrog's gull is monogamous and nests in dense colonies. The nest is on rock, sand, or shingle and is usually lined with vegetation, but sometimes with seaweed, feathers, shells or bones. Two or three olive-brown eggs with brown splotches are laid and the incubation period is about 30 days. Fledging takes place between November and January according to the location of the colony. [6]
The Mediterranean gull is a small gull. The scientific name is from Ancient Greek. The genus Ichthyaetus is from ikhthus, "fish", and aetos, "eagle", and the specific melanocephalus is from melas, "black", and -kephalos "-headed".
The common gull or sea mew is a medium-sized gull that breeds in the Palearctic. The closely related short-billed gull is sometimes included in this species, which may be known collectively as "mew gull". Many common gulls migrate further south in winter. There are differing accounts as to how the species acquired its vernacular name.
The great black-backed gull is the largest member of the gull family. Described by the Cornell Lab of Ornithology as "the king of the Atlantic waterfront", it is a very aggressive hunter, pirate, and scavenger. It breeds on the European and North American coasts and islands of the North Atlantic and is fairly sedentary, though some move farther south or inland to large lakes or reservoirs. The adult great black-backed gull has a white head, neck and underparts, dark grey wings and back, pink legs and yellow bill.
The lesser black-backed gull is a large gull that breeds on the Atlantic coasts of Europe. It is migratory, wintering from the British Isles south to West Africa. It has increased dramatically in North America, most common along the east coast. Formerly just a winter visitor, many birds are now spotted year-round. Some winters they occur in large numbers. Even on the west coast, this species has become an annual winter visitor in California with birds reported around most of the state each winter. They've even been seen in numbers at the Salton Sea. There is now serious concern about declines in many parts of the species range. The species is now on the RSPB Amber List because the UK is home to 40 per cent of the European population and more than half of these are found at fewer than ten sites.
The little gull, is a species of gull belonging to the family Laridae which is mainly found in the Palearctic with some colonies in North America. It breeds on freshwaters but winters at sea. It is the smallest species of gull in the world. It is the only species in the monospecific genus Hydrocoloeus.
The ring-billed gull is a medium-sized gull. The genus name is from Latin Larus which appears to have referred to a gull or other large seabird. The specific delawarensis refers to the Delaware River.
The Caspian gull is a large gull and a member of the herring and lesser black-backed gull complex. The scientific name is from Latin. Larus appears to have referred to a gull or other large seabird, and cachinnans means 'laughing', from cachinnare 'to laugh'.
The royal tern is a tern in the family Laridae. The species is endemic to the Americas, though strays have been identified in Europe.
The California gull is a medium-sized gull, smaller on average than the herring gull, but larger on average than the ring-billed gull. It lives not just in California, but up and down the entire Western coast of North America, and has breeding ground inland. The yellow bill has a black ring.
Heermann's gull is a gull resident in the United States, Mexico and extreme southwestern British Columbia, nearly all nesting on Isla Rasa in the Gulf of California. They are usually found near shores or well out to sea, very rarely inland. The species is named after Adolphus Lewis Heermann, nineteenth-century explorer and naturalist.
The yellow-footed gull is a large gull, closely related to the western gull and thought to be a subspecies until the 1960s. It is endemic to the Gulf of California.
The black-tailed gull is a gull native to shorelines of East Asia.
The grey gull, also known as garuma gull is a medium-sized gull native to South America. Unusual among gulls, it breeds inland in the extremely dry Atacama Desert in northern Chile, although it is present as a non-breeding bird along much of the Pacific coast of South America.
Belcher's gull, also known as the band-tailed gull, is a bird in the family Laridae found along the Pacific coast of South America. It formerly included the very similar Olrog's gull as a subspecies, but that bird occurs on the Atlantic coast of South America and is now accepted as Larus atlanticus. Belcher's gull is a medium-sized gull with a blackish mantle, white head and underparts, a black band on the otherwise white tail, and a yellow bill with a red and black tip. Non-breeding adults have a brownish-black head and a white eye-ring. The name of this bird commemorates the British explorer Sir Edward Belcher who performed survey work on the Pacific coast of South America.
The brown-hooded gull is a species of gull found in Argentina, Brazil, Chile, the Falkland Islands, and Uruguay. Its specific epithet, maculipennis, means 'spotted wings'. It is a white bird with a brown head and red beak and feet.
Saunders's gull or the Chinese black-headed gull, is a species of gull in the family Laridae. It is found in China, Hong Kong, Japan, North Korea, South Korea, Macau, Russia, Taiwan, and Vietnam. Its natural habitats are estuarine waters and intertidal marshes. As with many other gulls, it has traditionally been placed in the genus Larus, but based on phylogenetic work some have moved it to Chroicocephalus, while others argue it is sufficiently distinct for placement in the monotypic Saundersilarus. It is threatened by habitat loss. One of its few remaining strongholds are the Yancheng Coastal Wetlands, which hosts about 20% of the world's population. The Saunders's gull is named after the British ornithologist Howard Saunders.
The Andean gull is a species in subfamily Larinae of the family Laridae, the gulls, terns, and skimmers. It is found in Argentina, Bolivia, Chile, Colombia, Ecuador, and Peru.
The snowy-crowned tern, also known as Trudeau's tern, is a species of bird in subfamily Sterninae of the family Laridae, the gulls, terns, and skimmers. It is found in Argentina, Brazil, Chile, Uruguay, and possibly Paraguay, and also as a vagrant to Peru and the Falkland Islands,.
Olrog's cinclodes is a species of bird in the Furnariinae subfamily of the ovenbird family Furnariidae. It is endemic to Argentina.
The American herring gull or Smithsonian gull is a large gull that breeds in North America, where it is treated by the American Ornithological Society as a subspecies of herring gull.