Belcher's gull | |
---|---|
Breeding adult | |
Non-breeding adult | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Charadriiformes |
Family: | Laridae |
Genus: | Larus |
Species: | L. belcheri |
Binomial name | |
Larus belcheri Vigors, 1829 | |
Belcher's gull (Larus belcheri), 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.
Belcher's gull grows to a length of about 49 centimetres (19 in). The sexes are similar in appearance, and in the breeding season, the adult has a white head and very pale grey neck and underparts. The mantle and back are greyish-black, and the tail is white with a broad black subterminal band and a white trailing edge. The wing coverts and primaries are black and the secondaries dark grey with white tips. The eye is black, the bill yellow with a distinctive red and black tip, and the legs and feet yellow. Outside the breeding season the head is dark brown with a white ring surrounding the eye. The juvenile is mottled brown and white and attains the adult plumage during its third year. [2] [3]
Belcher's gull can be confused with the slightly larger kelp gull (Larus dominicanus), but that species has a small white tip on its otherwise black wing and lacks the black tail band found on Belcher's gull. [2]
Belcher's gull is found on the Pacific coast of South America. Its range extends from northern Peru to northern Chile in the area influenced by the Humboldt Current. Its habitat includes rocky shores, bays and offshore islands. It ventures several kilometres offshore to forage and also feeds on rocky shores when the tide is out. It is a non-migratory species. [4] [5]
Belcher's gull is an omnivore and scavenger. It feeds on fish, crabs, molluscs and carrion, and seasonally on the eggs and nestlings of seabirds. [4] It often associates with Guanay cormorants, pestering them until they regurgitate their prey, which it then consumes. [2]
Breeding takes place from December onwards in small colonies of up to one hundred pairs. The nest is a scrape in the sand or among rocks near the high tide line. [4]
There are usually three eggs averaging 65 by 45 mm (2.6 by 1.8 in), pale blotched with dark olive markings. [3]
Belcher's gull is estimated to have a total population of under ten thousand individuals and an estimated distribution range of 280,000 square kilometres (110,000 sq mi). Persecution of this bird by humans has diminished, and its population is thought to be increasing. For these reasons, despite its small total population size and limited range, the International Union for Conservation of Nature considers it to be of "least concern". [4]
Gulls, or colloquially seagulls, are seabirds of the family Laridae in the suborder Lari. 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 Larus, but that arrangement is now considered polyphyletic, leading to the resurrection of several genera. An older name for gulls is mews; this still exists in certain regional English dialects and is cognate with German Möwe, Danish måge, Swedish mås, Dutch meeuw, Norwegian måke/måse, and French mouette.
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 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 and reservoirs. The adult great black-backed gull has a white head, neck and underparts, dark grey wings and back, pink legs and yellow bill.
Pallas's gull, also known as the great black-headed gull, is a large bird species. As is the case with many gulls, it has traditionally been placed in the genus Larus. The scientific name is from Ancient Greek. Ichthyaetus is from ikhthus, "fish", and aetos, "eagle".
The yellow-legged gull is a large gull found in Europe, the Middle East and North Africa, which has only recently achieved wide recognition as a distinct species. It was formerly treated as a subspecies of either the Caspian gull L. cachinnans, or more broadly as a subspecies of the herring gull L. argentatus. The genus name is from Latin Larus which appears to have referred to a gull or other large seabird, and the species name honours the German zoologist Karl Michahelles.
Sabine's gull is a small gull. It is usually treated as the only species placed in the genus Xema, though some authors include it with other gulls in a wide view of the genus Larus. It has also been known historically as fork-tailed gull or "xeme". It breeds in colonies on arctic coasts and tundra, laying two or three spotted olive-brown eggs in a ground nest lined with grass. Sabine's gull is pelagic outside the breeding season. It takes a wide variety of mainly animal food, and will eat any suitable small prey.
The silver gull 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, which also lives in Australia.
The kelp gull, 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, and New Zealand. L. d. vetula is a subspecies occurring around Southern Africa.
The western gull is a large white-headed gull that lives on the west coast of North America and the Pacific Ocean. The western gull ranges from British Columbia, Canada, to Baja California, Mexico.
The glaucous-winged gull is a large, white-headed gull. The genus name is from Latin Larus which appears to have referred to a gull or other large seabird. The specific glaucescens is Neo-Latin for "glaucous" from the Ancient Greek, glaukos, denoting the grey color of its wings.
The swallow-tailed gull is an equatorial seabird in the gull family, Laridae. It is the only species in the genus Creagrus, which derives from the Latin Creagra and the Greek kreourgos which means butcher, also from kreas, meat; according to Jobling it would mean "hook for meat" referring to the hooked bill of this species. It was first described by French naturalist and surgeon Adolphe-Simon Neboux in 1846. Its scientific name is originally derived from the Greek word for gull, "Glaros" and via Latin Larus, "gull" and furca "two-tined fork". It spends most of its life flying and hunting over the open ocean. The main breeding location is in the Galápagos Islands, particularly the rocky shores and cliffs of Hood, Tower and Wolf Islands, with lower numbers on most of the other islands. It is more common on the eastern islands where the water is warmer.
The Armenian gull is a large gull found in the Caucasus and the Middle East. It was formerly classified as a subspecies of the European herring gull, but is now generally considered to be a separate species, although BirdLife International lumps it with the yellow-legged gull.
Hartlaub's gull, also known as the king gull, it is a small gull. It was formerly sometimes considered to be a subspecies of the silver gull, and, as is the case with many gulls, it has traditionally been placed in the genus Larus but is now placed in the genus Chroicocephalus. The species' name commemorates the German physician and zoologist, Gustav Hartlaub.
The white-eyed gull is a small gull that is endemic to the Red Sea. Its closest relative is the sooty gull. The species is classed as Least Concern by the IUCN; human pressure and oil pollution are deemed the major threats. As is the case with many gulls, it has traditionally been placed in the genus Larus.
Olrog's gull 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. It has a rather restricted breeding range and is threatened by habitat loss, and the IUCN has rated it as being "near threatened".
Saunders's gull or Chinese black-headed gull, is a species of gull in the family Laridae. It is found in China, 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. In 2023, this transfer was accepted by the International Ornithologists' Union.
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 native to Argentina, Brazil, Chile, Uruguay, and possibly Paraguay, and also vagrant in Peru and the Falkland Islands.
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.
The short-billed gull is a medium-sized species of gull that breeds in northwestern North America. In North America, it was previously known as the mew gull, when it was considered conspecific with the palearctic common gull. Most authorities, including the American Ornithological Society in 2021, have split the two populations as distinct species.