Black-winged Kite

识别特征

This long-winged raptor is predominantly grey or white with black shoulder patches, wing tips and eye stripe. The long falcon-like wings extend beyond the tail when the bird is perched. In flight, the short and square tail is visible and it is not forked as in the typical kites of the genus Milvus. When perched, often on roadside wires, it often adjusts its wings and jerks its tail up and down as if to balance itself. The sexes are alike in plumage. Their large forward-facing eyes placed under a bony shelf that shades them is distinctive; their velvety plumage and zygodactyl feet are characters shared with owls and the genus has been considered as a basal group within the Accipitridae. They are thought to have been adapted for living in savanna habitats where seasonal rodent population peaks occur. Such food resources are also favoured by the owls. The inner vanes of the feathers have velvety barbules. They have a diploid chromosome number of 68 (some older studies claimed 64 for E.c.caeruleus and 66 for E.c.vociferus) with a distinct karyotype with resemblances to the kites and honey buzzards and suggesting a basal position within the diurnal birds of prey.

分类信息

The black-winged kite was described by the French naturalist René Louiche Desfontaines in 1789 and given the binomial name Falco caeruleus. It is now one of four species in the genus Elanus which was introduced in 1809 by the French zoologist Jules-César Savigny. The genus Elanus is distinctive in having very small scales covering the foot and on the underside, scutellate scales are found only under the terminal phalanges. The claw lacks a groove on the underside. The word Elanus is from Ancient Greek elanos for a "kite". The specific epithet caeruleus is the Latin for "blue".<p>There are three subspecies:

学名

Elanus caeruleus

命名信息

(Desfontaines, 1789)

目

Accipitriformes

科

Accipitridae

属

Elanus

分布与栖息地

The black-winged kite is a species primarily of open land and semi-deserts in sub-Saharan Africa and tropical Asia, but it has a foothold within Europe in Spain and Portugal. The species range appears to be expanding in southern Europe and, more recently, also to West Asia. The first records of breeding in Europe were in the 1860s and since then they have become more widespread and populations are on the rise. It is thought that land-use changes, particularly agriculture and pastureland have helped the species. The species has expanded its range in southern Europe.<p>Several geographic populations have been named as subspecies and these include the nominate subspecies which occurs in Spain, Africa and Arabia. The subspecies vociferus is found east of this range across South Asia and into Southeast Asia. Along Sumatra, Java, Borneo and the Philippines subspecies hypoleucus (sometimes considered a full species) includes the population wahgiensis described from New Guinea. The subspecies sumatranus is not always recognized. The white-tailed kite and the black-shouldered kite were formerly included with this species but have since been treated as separate species.<p>Although found mainly on the plains they have been seen at higher altitudes in Sikkim (3,650 m (11,980 ft)), the Nilgiris (Doddabetta, 2,670 m (8,760 ft)) and Nagaland (2,020 m (6,630 ft)).<p>They are said to be winter visitors in some parts of their range such as the Western Ghats.

迁徙

Resident species

行为

Migration pattern: Resident species.

保护状况

Population trend: stable.

种群趋势

stable