White-crowned Forktail

识别特征

The white-crowned forktail is the largest of the forktails. Between 25 and 28 centimetres (9.8 and 11.0 in) long, the white-crowned forktail typically weighs between 27 and 38 grams (0.95 and 1.34 oz), though specimens weighing up to 53 grams (1.9 oz) have been reported. It has black feathering on its throat extending down to its breast, as well as a black face and scapulars. The crown and forehead have a prominent white patch, sometimes visible as a slight crest, from which the bird gets its name. The belly of the bird is white, and is sharply delineated from the throat and face. The lower back and rump of the bird are white. The tail of the species is long and evenly graduated, with a deep fork. It has white tips, and the outer feathers are white. It also has three narrower white bands created by the tips of shorter tail feathers. The wings of this species are largely black with a prominent white band across the greater coverts. Juveniles of the species have brownish black upperparts, breast, and throat, brown flanks, and brown mottling on the belly. They also lack the prominent white crown. The bill of the species is black, while the feet are pinkish in color.<p>Its mantle is completely black, a feature used to distinguish the species from the spotted forktail, which has a speckled mantle, and from the slaty-backed forktail, which has a slate-grey mantle. It is distinguished from the black-backed forktail by its longer tail and larger size. The Indian subspecies E. l. indicus has a bill slightly longer than the nominate subspecies E. l. leschenaulti, while the bill of the Chinese subspecies E. l. sinensis is slightly shorter than that of the nominate. The subspecies frontalis is somewhat smaller than the others, and the extent of white on its crown is smaller: E. l. borneensis is similar to frontalis but has a longer tail. E. l. chaseni is larger than birds from the rest of Sumatra, and also has a longer tail.<p>Multiple calls have been observed. The alarm call and contact calls are high-pitched, ringing lengthy whistles, described as "tseee, tseee" or "zweeet": these calls are repeated multiple times, with pauses in between. The alarm call is harsher and more emphatic, described as "scree" or "scree chit chit". Males use a long and complex whistled song when displaying or exhibiting territorial behavior; this often consists of a long whistle that fades away, followed by shorter whistles, clicking or chacking noises, or bell-like sounds. The call of the borneensis subspecies is slightly different from the others.

分类信息

The white-crowned forktail was formally described in 1818 by French ornithologist Louis Vieillot based on a specimen that had been collected in Java. Vieillot placed it with the thrushes in the genus Turdus and coined the binomial name Turdus leschenaulti. The specific epithet was chosen to honour the French naturalist and collector Jean-Baptiste Leschenault de La Tour. The white-crowned forktail is now one of eight forktails placed in the genus Enicurus that was introduced in 1822 by the Dutch zoologist Coenraad Jacob Temminck.<p>Five subspecies are recognised.<p>The species was found to be more distantly related to the slaty-backed forktail and the little forktail than to other forktail species. The precise geographic delineation between E. l. borneensis and E. l. frontalis is not known. It is closely related to the Bornean forktail (Enicurus borneensis) which replaces it in mountain areas of Borneo. E. borneensis was previously considered a sixth subspecies of the white-crowned forktail. It is genetically distinct from the white-crowned forktail, but morphologically similar.

学名

Enicurus leschenaulti

命名信息

(Vieillot, 1818)

目

Passeriformes

科

Muscicapidae

属

Enicurus

分布与栖息地

The habitat of the white-crowned forktail is subtropical or tropical regions in moist lowland forests and moist broadleaf montane forests. As is the case with other forktail species, the white-crowned forktail frequents fast-flowing rivers, waterfalls, and streams within the forests, though it may move to slower moving water sources in the winter. Its elevational range has been observed to vary seasonally, and in the northeastern regions of the Indian subcontinent, it is likely to migrate seasonally; all records from Bangladesh are from winter months. It also frequents damp areas and pools within the forest, including animal wallows, swampy areas, and water ditches. It may be found along slower-moving rivers and streams in the lowland regions of its distribution. It prefers areas screened by dense vegetation. On the island of Borneo the white-crowned forktail is sometimes found in drier areas, including along tracks and ridges in the forest, and in heathland.<p>The white-crowned forktail has a wide geographic distribution across south and south-east Asia, including in parts of India, Bangladesh, China, Myanmar, Bhutan, Thailand, Laos, Vietnam, Malaysia, and Indonesia . The elevational range of the species varies across its geographic distribution. In the Eastern Himalayas the species is generally found below 800 metres (2,600 ft) above sea level, though occasionally found till 1,250 metres (4,100 ft), and exceptionally at 2,400 metres (7,900 ft) in the state of Arunachal Pradesh. In Sumatra and Borneo it is generally seen up to an elevation of 1,400 metres (4,600 ft). The subspecies borneensis is found at 900–1,950 metres (2,950–6,400 ft), but occasionally as low as 185 metres (607 ft). It is common through most of its range but uncommon in the Himalayas. In the Chinese portion of its range, it is reported to be the most common forktail. Though the population of the species is not precisely known, it is thought to be greater than 10,000 individuals, and is estimated to be stable. It is categorized as a species of least concern by the International Union for Conservation of Nature.

迁徙

Resident species

行为

Migration pattern: Resident species.

保护状况

Population trend: stable.

种群趋势

stable