Mistle Thrush

识别特征

The mistle thrush is the largest thrush native to Europe. The nominate subspecies measures 27–28 cm (11–11 in) in length, with a 45 cm (18 in) wingspan. It weighs 93 to 167 g (3.3 to 5.9 oz), with an average of around 130 g (4.6 oz). It has a stocky upright posture when on the ground. It has pale grey-brown upperparts, the chin and throat are greyish-white, and the yellowish-buff breast and off-white belly are marked with round black spots. The spotting becomes denser on the lower chest, giving the appearance of a breast-band. The long tail has white tips on the outer feathers, and the underwing coverts are white. The eyes are dark brown and the bill is blackish with a yellowish base to the lower mandible. The legs and feet are yellowish-brown. There are no plumage differences between the sexes. Juveniles are similar to adults, but they have paler upperparts with creamy centres to many of the feathers and smaller spots on the yellowish underparts. By their first winter they are very similar to adults, but the underparts are usually more buff-toned.<p>The eastern subspecies T. v. bonapartei is 30 cm (12 in) in length, and therefore slightly larger than the nominate form. It is paler grey above and whiter below, with fewer black spots. Birds of intermediate appearance are seen west of the Ob River where the range overlaps with viscivorus. The southern race T. v. deichleri resembles bonapartei in appearance, but is closer in size to the nominate viscivorus, although it has a more slender bill.<p>Adults have a full moult after breeding, beginning between late May and the end of June, and completed by early October. Juvenile birds have a partial moult, replacing their head, body, and covert feathers; this is completed by October, although the start of the moult depends on when the chicks hatched.<p>The mistle thrush is much larger, paler and longer-tailed than the sympatric song thrush. In the western Himalayas it could be confused with both the plain-backed and the long-tailed thrushes. These are similar to the mistle thrush, but the plain–backed thrush lacks obvious wing bars, is more rufous above than its relative, and is barred rather than spotted below. The long-tailed thrush has olive-toned upperparts, bars on its breast and two wing bars. Juvenile mistle thrushes are superficially similar to White's thrush, but that species has golden-yellow plumage, scalloped underparts and a distinctive underwing pattern.<p>The male mistle thrush has a loud melodious song with fluted whistles, sounding like chewee-trewuu ... trureetruuruu or similar, repeated three to six times, and used to advertise his territory, attract a mate and maintain the pair bond. The tone resembles that of the song thrush or blackbird, but compared to its relatives the mistle thrush's repertoire is less varied and the delivery is slower. The song is, however, much louder, often audible up to 2 km (2,000 yd) away. The song is given from a treetop or other elevated position mainly from November to early June. The male is most vocal in the early morning, and its tendency to sing after, and sometimes during, wet and windy weather led to the old name "stormcock". The song may be heard in any month, although it is uncommon from July to August while the thrush is moulting. The main call, given by both sexes, is a dry chattering krrrr, louder when it is alarmed or excited. It is often likened to the sound of a football rattle, a form of musical ratchet. There is also a squeaky tuk contact call.

分类信息

The mistle thrush was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae under its current scientific name. Turdus is the Latin for "thrush", and viscivorus, "mistletoe eater", comes from viscum "mistletoe" and vorare, "to devour". The bird's liking for mistletoe berries is also indicated by its English name, "mistle" being an old name for the plant.<p>There are more than 60 species of medium to large thrushes in the genus Turdus, characterised by rounded heads, longish pointed wings, and usually melodious songs. A mitochondrial DNA study identified the mistle thrush's closest relatives as the similarly plumaged song and Chinese thrushes; these three species are early offshoots from the Eurasian lineage of Turdus thrushes after they spread north from Africa. They are less closely related to other European thrush species such as the blackbird (T. merula) which are descended from ancestors that had colonised the Canary islands from Africa and subsequently reached Europe from there.<p>At least eight subspecies have been proposed, but the differences between them are mainly clinal, with birds being paler and less densely spotted in the east of the range. The accepted subspecies as of 2000 are:<p>An isolated population in Crimea has sometimes been separated as T. v. tauricus, but this is not considered to be a valid form. Mistle thrush fossils have been found in Pleistocene deposits from Poland and Sicily.

学名

Turdus viscivorus

命名信息

Linnaeus, 1758

目

Passeriformes

科

Turdidae

属

Turdus

分布与栖息地

The mistle thrush breeds in much of Europe and temperate Asia, although it is absent from the treeless far north, and its range becomes discontinuous in southeast Europe, Turkey and the Middle East. In these warmer southern areas, it tends to be found in the milder uplands and coastal regions. Nominate T. v. viscivorus breeds in Europe and in Asia east to the Ob, beyond which it is replaced by T. v. bonapartei. The southern form T. v. deichleri is resident in North Africa, Corsica and Sardinia.<p>The mistle thrush is a partial migrant: birds from the north and east of the range wintering in the milder areas of Europe and North Africa. Scandinavian and Russian birds start moving south from mid-September onwards, most birds wintering in Europe, western Turkey and the Middle East. Between mid-October and November, large numbers cross the Strait of Gibraltar and others pass through Cyprus, but there is hardly any migration across the North Sea. Breeding birds in the British Isles and north-west Europe are resident or move only short distances. In the Himalayas, the breeding population moves to nearby lower-altitude sites in winter. Return migration starts mainly from late March, although it can be a month earlier in the Middle East, and northern breeders may not arrive back on their territories until late April or early May. Migration may be by day or night, and typically involves individuals or small groups. Vagrant birds have occurred in the Azores, China, Crete, Faroe Islands, Iceland, Japan, Oman, Saudi Arabia, Sikkim and the United Arab Emirates. In the winter 2017/2018 the first record of a mistle thrush for North America was at Miramichi in New Brunswick.<p>The mistle thrush is found in a wide range of habitats containing trees, including forests, plantations, hedges and town parks. In the south and east of its range, it inhabits upland coniferous woodland and the range extends above the main tree line where dwarf juniper is present. Breeding occurs at up to 600 m (2,000 ft) in the mountains of North Africa, and occasionally much higher, to 1,700 m (5,600 ft). In the highlands of Europe, its preferred altitude is from 800–1,800 m (2,600–5,900 ft). More open habitats, such as agricultural land, moors and grassy hills, are extensively used in winter or on migration.<p>There is evidence that this species has changed its natural habitat in at least parts of its range. In Germany and elsewhere in central Europe, it was found only in coniferous forest until the mid-1920s when its range rapidly expanded, first into farmland, and then to suburbs and urban parks. The reasons for this expansion are unclear. In areas of intensive farming, such as eastern England, arable land has in turn largely been abandoned in favour of built-up areas with their greater variety of green habitats.<p>Perhaps the most notable find of the 118th Christmas Bird Count in Canada was a single vagrant mistle thrush found in Miramichi, New Brunswick. This was the first record for this species in North America. The discovery attracted many birders from Canada and the United States; sightings continued from early December 2017 through late March 2018.

繁殖区

PAL : c, w, also n Africa

非繁殖区

n Africa and s Asia

迁徙

Complete migrants

行为

Migration pattern: Complete migrants.

保护状况

Population trend: declining.

种群趋势

declining