Pallas's Gull
Ichthyaetus ichthyaetus
Large powerful gull of saline, brackish, and fresh water bodies. Breeding adult has a black head with a thin incomplete crescent around the eye and a red-and-black-tipped bill. Nonbreeding adults retain a partial “hood” of patchy black on the back of the head. Young birds also have this dark patch, though it is much smaller in size. The eye crescents and a flashing white rump help to distinguish first-winter birds from Herring-type gulls. Can be readily separated by size in any plumage from the smaller dark-headed gulls.
识别特征
This is a very large gull, being easily the world's largest black-headed gull and the third largest species of gull in the world, after the great black-backed gull and the glaucous gull. It measures 55–72 cm (22–28 in) in length with a 142 to 170 cm (56 to 67 in) wingspan. Weight can vary from 0.96–2.1 kg (2.1–4.6 lb), with an average of 1.6 kg (3.5 lb) in males and 1.22 kg (2.7 lb) in females. Among standard measurements, the wing chord is 43.5 to 52 cm (17.1 to 20.5 in), the bill is 4.7 to 7.3 cm (1.9 to 2.9 in) and the tarsus is 6.5 to 8.4 cm (2.6 to 3.3 in). Summer adults are unmistakable, since no other gull of this size has a black hood. The adults have grey wings and back, with conspicuous white "mirrors" at the wing tips. The legs are yellow and the bill is orangey-yellow with a red tip.<p>In all other plumages, a dark mask through the eye indicates the vestiges of the hood. The call is a deep aargh cry. Young birds attain largely grey upperparts quite rapidly, but they take four years to reach maturity.
分类信息
- 学名
- Ichthyaetus ichthyaetus
- 命名信息
- (Pallas, 1773)
- 目
- Accipitriformes
- 科
- Accipitridae
- 属
- Ichthyaetus
分布与栖息地
This species breeds in colonies in marshes and islands from southern Russia to Mongolia. It is migratory, wintering in the eastern Mediterranean, Arabia and India. This gull nests on the ground, laying between two and four eggs.<p>It occurs in western Europe only as a vagrant. In Great Britain a recent review left a single occurrence in 1859 as the only acceptable record of this bird. The species also occurs as a vagrant in differing parts of the Indian Ocean, south of its normal range, and along the northern and eastern coasts of Africa, where it visits annually on an irregular basis.
- 繁殖区
- PAL : patchily on lake islands from Crimea to Kazakhstan, w, s Mongolia, Gansu, Qinghai and Inner Mongolia (w, c China)
- 非繁殖区
- to coasts of Black, Caspian, and Aral seas; Red Sea, Persian Gulf, Arabian Sea and Bay of Bengal (North Indian Ocean) to Bangladesh and Gulf of Martaban (sc Myanmar); also large n, c rivers of India and Myanmar
- 迁徙
- Complete migrants
行为
This bird has a deep, rather nasal flight-call which resembles the call of the lesser black-backed gull. Although they are noisy at colonies, Pallas's gulls are mostly silent when breeding.<p>These birds are predatory, taking fish, crustaceans, insects and even small mammals.<p>The Pallas's gull is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies.
保护状况
- 种群趋势
- rising
照片
分布
鸟叫声
其他鸟类
Spot-winged Falconet
Spiziapteryx circumcincta
Small, distinctive falcon of the Chaco from central Argentina to SE Bolivia and W Paraguay, often seen on tall, exposed perches. Small size and bold white supercilium and malar distinctive. Generally uncommon and in low density throughout range. Call distinctive for a raptor: a slightly warbled, full “skyoot” note given repeatedly.
Rodrigues Warbler
Acrocephalus rodericanus
A medium-sized yellowish-olive bird with a long tail that is often flipped up and down. Endemic to the remote island of Rodrigues. Found in secondary forest, scrub, and plantations. Feeds both in the undergrowth and up into the canopy. The cheerful song is a quick series of several musical warbling notes in an up-and-down pattern. The calls include “chek” notes and rattling scolds. There are no other warblers or otherwise similar species on Rodrigues, so identification is simple.
Siberian Blue Robin
Larvivora cyane
A slender, long-legged songbird with a “crouched” profile. Adult male is unmistakable, with blue upperparts and snow-white belly separated by black running from the eye to the bend of the wing. Female warm brown with blue-tinted rump and whitish underparts. Juvenile resembles female but grayer above. Like most other robins, shy and retiring, inhabiting forested areas with dense undergrowth; on its breeding grounds, most easily detected by its song, an explosive “tsi-tsi-TEWEE-TEWEE.”
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