The slaty-backed forktail (''Enicurus schistaceus'') is a species of
forktail in the family
Muscicapidae
The Old World flycatchers are a large family, the Muscicapidae, of small passerine birds restricted to the Old World (Europe, Africa and Asia), with the exception of several vagrants and two species, Bluethroat (''Luscinia svecica)'' and North ...
. A slim, medium-sized forktail, it is distinguished from similar species by its
slate grey
Slate gray is a gray color with a slight azure tinge that is a representation of the average color of the material slate. As a tertiary color, slate is an equal mix of purple and green pigments.
Slaty, referring to this color, is often used t ...
forehead, crown, and mantle. It has a long and deeply forked tail banded in black and white, a white rump, and a white bar across its primary feathers; the rest of the plumage is predominantly white. The sexes look alike. The bird frequents the edges of fast-flowing streams and rivers, where it hunts small invertebrates by hopping among rocks or flying out over the water. It breeds between February and July, laying 3–4 pinkish, bluish, or white eggs; both sexes incubate the eggs.
The slaty-backed forktail is found near streams and rivers in tropical and subtropical regions, occasionally straying further from flowing water to the edges of roads and trails. Generally a solitary bird, it may occasionally be found in pairs, or in family groups in the breeding season. One of its calls has been described as similar to that of the
Blyth's kingfisher, for which it has been mistaken. The forktail is found in the central and eastern
Himalayas
The Himalayas, or Himalaya (; ; ), is a mountain range in Asia, separating the plains of the Indian subcontinent from the Tibetan Plateau. The range has some of the planet's highest peaks, including the very highest, Mount Everest. Over ...
, the
Indian Sub-continent
The Indian subcontinent is a physiographical region in Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian Ocean from the Himalayas. Geopolitically, it includes the countries of Bangladesh, Bhutan, India, ...
, southern China and continental Southeast Asia. Its wide distribution and apparently stable population have led to it being classified as a species of least concern by the
International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natur ...
.
Taxonomy and systematics
The slaty-backed forktail was described scientifically in 1836 by British naturalist
Brian H. Hodgson. It was originally placed in a new subgenus ''Enicurus'' in the genus ''
Motacilla'', which contains the wagtails.
The specimen used to describe the species came from Nepal.
The species name is the
Latin
Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power ...
adjective ''schistaceus'' "slaty-grey". The slaty-backed forktail is currently placed within the family
Muscicapidae
The Old World flycatchers are a large family, the Muscicapidae, of small passerine birds restricted to the Old World (Europe, Africa and Asia), with the exception of several vagrants and two species, Bluethroat (''Luscinia svecica)'' and North ...
, which includes
Old World flycatcher
The Old World flycatchers are a large family, the Muscicapidae, of small passerine birds restricted to the Old World (Europe, Africa and Asia), with the exception of several vagrants and two species, Bluethroat (''Luscinia svecica)'' and North ...
s and
chats.
[ A genetic study found that the slaty-backed forktail and the ]little forktail
The little forktail (''Enicurus scouleri'') is a species of bird in the family Muscicapidae. The specific name commemorates Dr John Scouler of Glasgow.
Description
The sexes are alike, with black and white plumage. Black above, with white for ...
were genetically more distinct from the white-crowned forktail
The white-crowned forktail (''Enicurus leschenaulti'') is a species of forktail in the family Muscicapidae. Scientifically described in 1818, it has five subspecies, each occupying a different geographic range. The largest of the forktails, ''E ...
than were other forktail species.
Description
The slaty-backed forktail is a slim, medium-sized forktail between long, and weighs between . It is coloured slate-grey, black, and white. The bill is black, while the feet of the bird are a pale pinkish or greyish colour. The iris has been described as dark brown, though it has been recorded as black in certain specimens. It has a black throat and a narrow white stripe across its face till just behind the eyes, sometimes describe as a white mask. The white stripe sometimes includes a white eye ring, which may be either complete or partial. Its ear coverts, chin, and face are also black. The forehead, crown, sides of the neck, and the scapular
The scapular (from Latin ''scapulae'', "shoulders") is a Western Christian garment suspended from the shoulders. There are two types of scapulars, the monastic and devotional scapular, although both forms may simply be referred to as "scapular ...
s are slate grey. It has black wing-coverts, a white patch at the base of the primaries, wide white bars on otherwise black wings, and also a large white patch on its rump and lower back. The bases of the flight feathers are white, which is occasionally visible as a little additional bar on the wing. The tail of the bird is long and evenly graduated, with a deep fork. The tail is largely black except for a white tip. It also has three white bands along its length, formed by the white tips of shorter tail feathers.
The juvenile of the species lacks a white forehead, is brown above, and has dark scales on its breast. The tail of the juvenile is shorter than that of the adult: juveniles also have greyish or yellowish lores, and greyish or white chin and throat. The flanks are a dull grey-brown. It is not sexually dimorphic
Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...
. Some specimens have been observed to have white tips to their primaries. This feature has been hypothesized to be the result of aging or of wear and tear, and has been observed throughout the distribution of the species. It is known not to be sex-related. Though very similar to the black-backed forktail ''Enicurus immaculatus'', it is distinguished by its slate-grey mantle and crown, from which it gets its name. It also has a slightly larger bill than the black-backed forktail, and slightly less white on its forehead.
Vocalisation
One of the slaty-backed forktail's calls has been described as a "high, thin, sharp, metallic screech, 'teenk'''", similar to that made by a small kingfisher
Kingfishers are a family, the Alcedinidae, of small to medium-sized, brightly colored birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species found in the tropical regions of Africa, Asia, and Oceania ...
; in particular, it has been mistaken for the call of the Blyth's kingfisher ''Alcedo hercules''. Another call is described as a mellow "''cheet''". It also produces a repeated, harsh screeching call when alarmed.
Distribution and habitat
The slaty-backed forktail is found near fast-flowing water bodies in tropical and sub-tropical montane
Montane ecosystems are found on the slopes of mountains. The alpine climate in these regions strongly affects the ecosystem because temperatures fall as elevation increases, causing the ecosystem to stratify. This stratification is a crucial ...
broadleaf forests, as well as near cultivated areas. These include rocky streams and rivers, including broad rivers and valleys in plains areas. A 2000 paper studying birds in northwest India and Nepal found that the incidence of slaty-backed forktails decreased with altitude. The study also found that the slaty-backed forktail had a preference for streams that were bordered by dense and complex vegetation, and had firm and stable banks of earth. They also preferred streams with finer grained sand on the bottom, and with "pool–riffle sequences." More rarely the bird is seen in secluded areas of the forest, and on the sides of roads or trails near the water. In winter months it has been observed to move from the mountains into foothills and plains areas.
The species is found in the central and eastern Himalayas, from the Indian state of Uttarakhand
Uttarakhand ( , or ; , ), also known as Uttaranchal ( ; List of renamed places in India, the official name until 2007), is a States and union territories of India, state in the North India, northern part of India. It is often referred to as t ...
in the west to Myanmar in the East, including Nepal, and Bhutan. It is a vagrant in Bangladesh. It is also found in southern China, in southeast Tibet, and in the provinces of Sichuan
Sichuan (; zh, c=, labels=no, ; zh, p=Sìchuān; alternatively romanized as Szechuan or Szechwan; formerly also referred to as "West China" or "Western China" by Protestant missions) is a province in Southwest China occupying most of th ...
, Yunnan
Yunnan , () is a landlocked province in the southwest of the People's Republic of China. The province spans approximately and has a population of 48.3 million (as of 2018). The capital of the province is Kunming. The province borders the ...
, Guizhou
Guizhou (; formerly Kweichow) is a landlocked province in the southwest region of the People's Republic of China. Its capital and largest city is Guiyang, in the center of the province. Guizhou borders the autonomous region of Guangxi to t ...
, Fujian
Fujian (; alternately romanized as Fukien or Hokkien) is a province on the southeastern coast of China. Fujian is bordered by Zhejiang to the north, Jiangxi to the west, Guangdong to the south, and the Taiwan Strait to the east. Its c ...
and Zhejiang
Zhejiang ( or , ; , also romanized as Chekiang) is an eastern, coastal province of the People's Republic of China. Its capital and largest city is Hangzhou, and other notable cities include Ningbo and Wenzhou. Zhejiang is bordered by ...
, and possibly in Hainan
Hainan (, ; ) is the smallest and southernmost province of the People's Republic of China (PRC), consisting of various islands in the South China Sea. , the largest and most populous island in China,The island of Taiwan, which is slight ...
. Its range in South-East Asia includes Thailand, Vietnam, Laos, Cambodia, peninsular Malaysia, and Hong Kong. In Hong Kong, it is only an occasional winter visitor or highly uncommon resident. Its distribution in southeast Asia is discontinuous. The elevational range of the slaty-backed forktail varies geographically. It has been estimated as 300-1600m above sea level in northern India, 900–1675 in Nepal, 400–1800 in southern China and the adjacent areas of Thailand, above 500m in Cambodia, above 800m in Malaysia, and 800-2200m in Bhutan. In the winter, it has been recorded as low as 200m above sea level.
The range of the species has not been precisely determined, but is known to be very large. The population is thought to be stable, and though its size is not precisely known, it is thought to be greater than 10,000 individuals. It is categorized as a species of least concern by the International Union for Conservation of Nature
The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natur ...
. It is common in the parts of its range that occur in China, Nepal, and South-East Asia.[
]
Behaviour and ecology
The slaty-backed forktail breeds between February and July; the breeding period does not appear to vary across its range. It builds a nest with materials including bryophyte
The Bryophyta s.l. are a proposed taxonomic division containing three groups of non-vascular land plants ( embryophytes): the liverworts, hornworts and mosses. Bryophyta s.s. consists of the mosses only. They are characteristically limited ...
s, leaves, and grass. The shape of the nest can be a cup or part of a dome, depending on where it is built.[ It frequently has an outer layer of mud. The nest may be constructed in holes in the ground or in the trunks of trees, between the roots of trees, in hollows of dead trees, and sometimes within crevices in rocks.] The bird lays three to four eggs that vary from pure white to pinkish white to bluish white, with lavender or reddish brown spots. The spots are more common on the larger end of the egg. Both sexes incubate the eggs. The species is thought to have two or three broods in a year.
The species feeds on small invertebrates found in or around the water, including larvae and crustaceans. It forages at the edge of the water, and is described as "moving restlessly". It forages on and among rocks at the edges of the water as well as in mid-stream; it will occasionally enter the water as well.[ Though it generally forages by hopping in an agile manner among rocks, it also makes brief forays above the water to snatch food items from the surface.] Its flight is described as similar to that of a large wagtail; quick and direct, and slightly undulating. It is seen mostly near the water; usually solitary, it is occasionally observed in pairs, and is described as a shy bird. It constantly bobs its tail, and when disturbed it may raise and open its tail with a quick scissor-like movement. In the breeding season is occasionally in small family groups, while in winter it is most often solitary. However, many birds may forage in a favored section of a stream: 15 birds have been observed along a single stretch of the river in Bhutan.
In the South-East Asian parts of its range the bird is sedentary, while in the Himalayas it is observed to move over an elevational gradient.[ A 1998 study found that the species moved locally in response to rising water levels in the monsoon season.]
References
External links
Image at ADW
Oriental Bird Images: ''Slaty-backed Forktail''
Selected images
{{Taxonbar, from=Q1589059
slaty-backed forktail
Birds of Nepal
Birds of Bhutan
Birds of Northeast India
Birds of China
Birds of Southeast Asia
slaty-backed forktail
Taxonomy articles created by Polbot