出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/03/26 14:42:10」(JST)
| Whinchat | |
|---|---|
| Adult male in breeding plumage in Belgium | |
| Conservation status | |
|
Least Concern (IUCN 3.1)[1] |
|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Muscicapidae |
| Genus: | Saxicola |
| Species: | S. rubetra |
| Binomial name | |
| Saxicola rubetra (Linnaeus, 1758) |
|
The Whinchat (Saxicola rubetra) is a small migratory passerine bird breeding in Europe and western Asia and wintering in Africa.
Its scientific name means "small rock-dweller", in reference to its habitat. Saxicola derives from Latin saxum ("rock") + incola ("dwelling"); rubetra is a Latin term for a small bird.[2][3]
This species represents a fairly basal divergence of the genus Saxicola. It retains the supercilium found in many Muscicapidae but lost in the more derived Saxicola species such as the European Stonechat or African Stonechat (S. torquatus).[4]
As with other species of Saxicola, it was formerly considered a member of the thrush family (Turdidae), but is now placed in the Old World flycatcher family Muscicapidae.[5] It, and similar thrush-like Muscicapidae species, are often called chats.
Very rarely, hybridisation between Whinchat and Siberian Stonechat occurs, with a case in reported Finland in 1997.[6]
The Whinchat is similar in size to its relative the European Robin (Erithacus rubecula), 12–14 cm long and 13–26 g weight. Both sexes have brownish upperparts mottled darker, a buff throat and breast, a pale buff to whitish belly, and a blackish tail with white bases to the outer tail feathers.[2][7]
The male in breeding plumage has blackish face mask almost encircled by a strong white supercilium and malar stripe, a bright orange-buff throat and breast, and small white wing patches on the greater coverts and inner median coverts. The female is duller overall, in particular having browner face mask, pale buffy-brown breast, and a buff supercilium and malar stripe, and smaller or no white wing patches. Males in immature and winter plumage and are similar to females, except that adult males retain the white wing patches all year.[2][8]
Though fairly similar to females and immatures of the European Stonechat S. rubicola, the Whinchat can readily be distinguished by its conspicuous supercilium and whiter belly, and also in western Europe, by being paler overall than the western European Stonechat subspecies S. rubicola hibernans. It also differs structurally in being slightly slimmer and less 'dumpy', and having longer wingtips (an adaptation to its long-distance migration). It is more easily confused with female or immature Siberian Stonechat S. maura, which (also being a long-distance migrant) shares the longer wingtips; however, Siberian Stonechat can be distinguished by its conspicuous unmarked pale orange-buff rump (in Whinchat, the rump is the same mottled brown colour as the back).[2]
Its main call is a hue-tac-tac, the 'tac' softer and less grating than that of the European Stonechat; the call is used both for contact between birds and predator alarms. The male has a whistling, crackly but soft song used during the breeding season, consisting of a mixture of soft whistles, tacs and more grating sounds; it is often mimetic, including phrases from the songs of at least 12 other assorted bird species. On the wintering grounds, it often gives alarm calls but only occasionally sings, particularly at the end of winter when starting spring migration.[2]
The Whinchat is a migratory species breeding in Europe and western Asia from Ireland and northern Portugal east to the Ob River basin near Novosibirsk, and from northern Norway south to central Spain, central Italy, northern Greece, and the Caucasus Mountains.[2]
Birds arrive on the breeding grounds between the end of April and mid May, and depart between mid August and mid September (odd birds lingering to October). They winter primarily in tropical sub-Saharan Africa from Senegal east to Kenya and south to Zambia, arriving in western Africa at the start of the dry season in late September to November, and leaving between February and March. Small numbers also winter in northwestern Africa in Morocco, northern Algeria and Tunisia.[2]
The Whinchat favours rough low vegetation habitats such as open rough pasture or similar minimally cultivated grassland with scattered small shrubs such as Hawthorn (Crataegus monogyna), and Bracken (Pteridium aquilinum) or Heather (Calluna vulgaris) stands on rock-strewn ground. They also commonly use new and clear-felled conifer plantations until the new tree crop is about 5–6 years old and a metre or two tall. It always needs at least a few perching points (shrubs, tall weeds, or fenceposts) to scan from for food and use as songposts. It nests in dense low vegetation, laying from four to seven eggs, which hatch after 11–14 days. The young leave the nest on foot 10–14 days after hatching, while still too young to fly; they then fledge at 17–19 days after hatching and remain largely dependent on the parents for up to a further two weeks after fledging.[2] Whinchats are short-lived, typically only surviving two years, to a maximum recorded of just over five years; breeding starts when birds are a year old.[3] Predators include Weasels, Stoats, and small raptors such as the Merlin and nest predators such as crows and magpies. Nests are also lost due to agricultural operations such as silage cutting (the main factor in the species' decline in western Europe[9]) or trampling by livestock, and are sometimes parasitised by Cuckoos.[2]
Whinchats are insectivorous, feeding largely (about 80-90%) on insects, but also a wide range of other invertebrates including spiders, small snails and worms. It also eats small amounts of fruit such as blackberries, primarily in autumn. The birds like to perch on elevated spots such as shrubs, from where they make sallies to catch insects, mostly taken off the ground, but also flying insects. While so perched, males in particular frequently flick their tail and sometimes their wings to show the white tail and wing flashes, for display or territorial communication signals to other Whinchats.[2]
Adult Whinchats have a single complex complete moult in late summer (late July onward) after breeding and mainly completed before southbound migration. Juveniles have a partial moult at the same time, growing new body feathering but retaining the flight feathers. All ages also have a partial moult in early spring on the wintering grounds before northbound migration.[2]
Fairly common across its wide range, the Whinchat is classified as a species of Least Concern by the IUCN.[1] Some populations are however in serious decline, particularly in the west of its range in Britain, Ireland, France, Belgium, the Netherlands, Denmark, and Germany, primarily due to agricultural intensification. In Britain it is amber-listed with an unfavourable conservation status; it all but disappeared from former lowland breeding areas in the south and east between surveys in 1968-72 and 1988–91, remaining common only in upland areas of the north and west where low-intensity livestock rearing is the main land use.[3][7][10] There has been a similar decline in Ireland.[11]
Vagrants have reached northwest of the breeding range to Iceland, west on migration to the Canary Islands and Cape Verde, and south of the wintering range to northern South Africa.[2]
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