紫鷺

识别特征

The purple heron is a large bird, 78–97 cm (31–38 in) in length with a standing height from 70 to 94 cm (28 to 37 in) and a 120–152 cm (47–60 in) wingspan. However, it is slender for its size, weighing only 0.5 to 1.35 kg (1.1 to 3.0 lb). It is somewhat smaller than the grey heron, from which it can be distinguished by its darker reddish-brown plumage, and, in adults, its darker grey back. Adults have the forehead and the crown of the head black, with a dark stripe down the back of the neck that terminates in a slender, dangling crest. This is shorter than the crest of the grey heron and does not exceed 140 mm (5.5 in). The sides of the head and the neck are buffish chestnut, with dark streaks and lines down either side of the whole the neck. The mantle is oily brown and the upper scapular feathers are elongated but not the lower ones. The rest of the upper parts and the tail are brownish grey. The front of the neck is paler than the sides and there are some elongated feathers at the base of the neck which are streaked with white, chestnut and black. The breast is chestnut brown, with some blackening at the side, and the belly and under-tail coverts are black. The brownish-yellow beak is long, straight and powerful, and is brighter in colour in breeding adults. The iris is yellow and the legs are brown at the front and yellowish behind.<p>The call is a harsh "frarnk", but is quieter and more high-pitched than that of the grey heron. It is generally a less noisy bird, though similar guttural sounds are heard emanating from the heronry. It is also less robust, and appears somewhat hollow-chested. Its head and neck are more slender and snake-like than the grey heron and its toes much longer. Unlike that bird, it often adopts a posture with its neck extending obliquely, and even nestlings tend to use this stance.

分类信息

There are three or four subspecies:<p>The scientific name comes from Latin ardea "heron", and purpureus, "coloured purple".

学名

Ardea purpurea

命名信息

Linnaeus, 1766

目

鹈鹕目

科

鹭科

属

Ardea

分布与栖息地

The purple heron has a mostly palaearctic distribution and breeds in Europe, Asia and Africa. The range of the western race extends from Portugal eastwards across much of central and southern Europe and parts of North Africa as far as Lake Balkhash in Kazakhstan. In Africa, the bird breeds in Senegal, down the east coast of Africa and in Madagascar. The eastern race extends from the Indian Subcontinent, eastwards to eastern China and the Philippines, and northwards to the basins of the Amur River and the Ussuri River at about 49°N. The southern race is restricted to Madagascar, and a small population of purple herons on the Cape Verde Islands is regarded as a separate race by some authorities.<p>Between August and October, birds of the western population migrate southwards to tropical Africa, returning northwards in March. Purple herons often overshoot their normal range on their return, and are vagrants to northern Europe including Britain. The eastern population is largely resident, though some birds from the northern part of the range fly southwards to Korea, Thailand and Malaysia. The African birds are resident.<p>The purple heron inhabits marshes, lagoons and lakes surrounded by dense vegetation. It may frequent mangrove swamps on the coast but it usually chooses freshwater habitats, particularly locations with Phragmites reed beds. It also visits mudflats, river banks, ditches and canals. In the Cape Verde Islands, it is more likely to be seen in the open, on arid slopes.

迁徙

完全迁徙鸟

行为

迁徙模式: 完全迁徙鸟.

保护状况

种群趋势: 下降.

种群趋势

下降