Belcher's gull (''Larus belcheri''), also known as the band-tailed gull, is a bird in the family

Laridae Laridae is a family of seabirds in the order Charadriiformes that includes the gulls, terns, skimmers and kittiwakes. It includes around 100 species arranged into 22 genera. They are an adaptable group of mostly aerial birds found worldwide. ...

found along the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

coast of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. It formerly included the very similar Olrog's gull as a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

, 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 Admiral Sir Edward Belcher (27 February 1799 – 18 March 1877) was a British naval officer, hydrographer, and explorer. Born in Nova Scotia, he was the great-grandson of Jonathan Belcher, who served as a colonial governor of Massachuse ...

who performed survey work on the Pacific coast of South America.

Description

Band-tailed Gull (Larus belcheri) (4856931950)

Belcher's gull grows to a length of about . 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. Belcher's gull can be confused with the slightly larger

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, part ...

(''Larus dominicanus'') but that species has a small white tip on its otherwise black wing and lacks the Belcher's gull's black band on its tail.

Distribution and habitat

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 The Humboldt Current, also called the Peru Current, is a cold, low- salinity ocean current that flows north along the western coast of South America.Montecino, Vivian, and Carina B. Lange. "The Humboldt Current System: Ecosystem components and pr ...

and 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.

Ecology

Belcher's gull is an

omnivore An omnivore () is an animal that has the ability to eat and survive on both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize the nutr ...

and

scavenger Scavengers are animals that consume dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a herbivorous feeding b ...

. It feeds on fish, crabs, molluscs and carrion, and seasonally on the eggs and nestlings of seabirds. It often associates with

Guanay cormorant The Guanay cormorant or Guanay shag (''Leucocarbo bougainvilliorum'') is a member of the cormorant family found on the Pacific coast of Peru and northern Chile. (The Argentinian population on the Patagonian Atlantic coast appears to be extirpat ...

s, pestering them until they regurgitate their prey which it then consumes. 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. There are usually three eggs averaging , pale blotched with dark olive markings.

Status

Belcher's gull is estimated to have a total population of under ten thousand individuals and an estimated distribution range of . 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 The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

considers it to be of "

least concern A least-concern species is a species that has been categorized by the International Union for Conservation of Nature (IUCN) as evaluated as not being a focus of species conservation because the specific species is still plentiful in the wild. T ...

References

{{Taxonbar, from=Q478233

Belcher's gull 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 South America is a continent entirely in the Western Hemisphere and mostly in the ...

Birds of Chile Birds of Ecuador Birds of Peru Western South American coastal birds