Belcher's Gull
Larus belcheri
Rather large, dark-backed gull along the Humboldt Current coast. Fairly common to locally common, favoring fishing harbors, beaches, and river mouths; ranges over inshore coastal waters and not found inland. All ages have a broad, clean-cut black tail band and a red-and-black bill tip. Breeding adult has clean white head and lacks the white spots in wingtip seen on the larger and bulkier Kelp Gull. Immature and nonbreeding plumages have a distinctive dark hood and yellowish legs.
识别特征
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. 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.
分类信息
- 学名
- Larus belcheri
- 命名信息
- Vigors, 1829
- 目
- Charadriiformes
- 科
- Laridae
- 属
- Larus
分布与栖息地
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 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.
- 繁殖区
- SA : w coast and islets of South America from n Peru to n Chile
- 非繁殖区
- some move to coasts of n Ecuador and c Chile
- 迁徙
- Resident species
行为
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. It often associates with Guanay cormorants, pestering them until they regurgitate their prey which it then consumes.<p>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 65 by 45 mm (2.6 by 1.8 in), pale blotched with dark olive markings.
保护状况
- 种群趋势
- rising
照片
分布
鸟叫声
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