Snowy-browed Nuthatch

识别特征

The Chinese nuthatch is a small nuthatch, measuring 11.5 cm (4.5 in) in length. The upperparts of the Chinese nuthatch are blue-gray, with the crown shiny black to dark gray; the underparts are light, ranging from dull buff-gray to cinnamon orange. The coloration varies a bit depending on the sex, plumage wear and subspecies. The species has a marked white supercilium, as well as a more or less well defined black eyestripe. The bill is thin and pointed, with the edge of the upper mandible (the culmen) straight, which may give the impression that the tip of the bill is rising upwards. The bill is slate-black, with the base of the lower mandible blue-gray. The iris is brown to dark brown, and the legs and toes are dull, blue-gray to brownish-gray.<p>There is a marked sexual dimorphism: the male has a very black crown and a clear black eyestripe framing a contrasting white supercilium, while in the female the crown is barely darker than the rest of the upperparts in fresh plumage, becomes a darker and more contrasting sooty-grey, especially on the forehead, and in some cases the entire crown is sooty-black. Its eyestripe is also less well defined, duller, and its supercilium thinner. The female is overall duller than the male, notably with the scapulars less vivid, the wing feathers edged with brown and the underparts darker and less colored. The juvenile male has a blacker crown than the darker female, but still less black and less bright than the adult male; its underparts are darker and more cinnamon-colored. In the nominate subspecies, juveniles also have cinnamon edging on their wing feathers, whereas the adult feather edges are generally duller, tending to gray. In the subspecies S. v. bangsi, adults have cinnamon feather margins, and are overall more colorful than subspecies S. v. villosa, with the male having orange-cinnamon and the female dull buff-cinnamon and dull underparts. However, in late winter, both subspecies have paler and fairly similar colorations. The subspecies S. v. corea is paler, more grayish, and smaller than the nominate subspecies<p>This species is locally found in sympatry with the Eurasian nuthatch (S. europaea), but differs from it in its smaller size, clearly visible white supercilium, black crown in males, and relatively plain underparts, lacking the reddish undertail coverts and flanks. In the west of its range, the Chinese nuthatch can also be found with Przevalski's nuthatch (S. przewalskii), and both have brightly cinnamon-colored underparts. The Chinese nuthatch is easily distinguished by its black eyestripe, while Przevalski's nuthatch has very light cheeks contrasting with the breast. The Chinese nuthatch is phylogenetically and morphologically very close to the Corsican nuthatch, which is, however, endemic to Corsica and generally has much less vivid underparts; a Chinese nuthatch in worn plumage has underparts that are just more buff than a Corsican nuthatch in fresh plumage. Both species are closely related to the red-breasted nuthatch, which has even brighter underparts, with a more prominent eye streak.

分类信息

The Chinese nuthatch was described in 1865 by the French ornithologist Jules Verreaux, based on specimens sent from Beijing by the missionary Armand David in 1862, who also referred to it as Sitta pekinensis in 1867. Verreaux described the species as close to red-breasted nuthatch (Sitta canadensis) but with long, silky plumage, and thus gave the specific name "villosa", from the Latin for "hairy". German ornithologist Hans Edmund Wolters proposed the division of the genus Sitta into subgenera in 1975–1982. The Chinese nuthatch is placed in Sitta (Micrositta). According to the International Ornithological Congress there are three subspecies:<p>The Japanese ornithologist Toku Tarô Momiyama also later used the name Sitta villosa yamashinai (Momiyama, 1931), but this name is not associated with any valid scientific description and therefore is a nomen nudum.<p>In 1998, Eric Pasquet studied the cytochrome-b of the mitochondrial DNA of a dozen nuthatch species, including the various species of the Sitta canadensis group, which are also those that comprise the subgenus Micrositta: canadensis, villosa, yunnanensis, whiteheadi, krueperi and ledanti. The Yunnan nuthatch (S. yunnanensis) is not included in the study. Pasquet concludes that the Chinese nuthatch is phylogenetically related to the Corsican nuthatch (S. whiteheadi) and the red-breasted nuthatch, these three species form the sister group of a clade including Krüper's nuthatch (S. krueperi) and the Algerian nuthatch (S. ledanti). The first three species would even be close enough to be conspecific. For the sake of taxonomic stability, however, all retain their status as species in their own right. In 2014, Eric Pasquet and colleagues published a phylogeny based on nuclear and mitochondrial DNA of 21 nuthatch species and confirmed the relationships of the 1998 study within the "canadensis group", adding the Yunnan nuthatch, which was found to be the most basal species of the group.<p><p>With its phylogeny established, Pasquet concludes that the paleogeographic history of the group would be as follows: the divergence between the two main clades of the "canadensis group" appears to have occurred more than five million years ago, at the end of the Miocene, when the common ancestor of krueperi and ledanti entered the Mediterranean basin at the time of the Messinian salinity crisis; the two species diverged 1.75 million years ago. The other clade split into three, with populations leaving Asia for the east, giving rise to the red-breasted nuthatch, and then from the west, about one million years ago, marking the separation between the Corsican and Chinese nuthatches.

学名

Sitta villosa

命名信息

Verreaux, J, 1865

目

Passeriformes

科

Sittidae

属

Sitta

分布与栖息地

The Chinese nuthatch is distributed over northeast China, Korea, and the extreme southeast of Russia. It has been reported from the Russian island of Sakhalin, but may only be a vagrant there. In China, it ranges from eastern Qinghai in the west to southeastern and central Gansu, most of Shaanxi, Shanxi, southern Liaoning on the Liaoning peninsula, northern Hebei, Beijing Municipality, and northern Sichuan. It was recorded from northern North Korea, with some dispersal into surrounding areas in autumn; it was observed in North Hamgyong in July–August and, in May–November, in North Kyongsang, including North P'yongan. It is a very rare winter visitor in South Korea, with records from the mountains of Kyonggi (October–March, also July 1917) and North Kyongsang in November; the only recent South Korean record is from the Kwangnung Experimental Forest, near Song, Kangwon province, in March 1968. In the peninsula, it is closely associated with Japanese Red Pine (Pinus densiflora) forests. In China, it inhabits coniferous forests (Pinus, Picea), sometimes mixed with oaks (Quercus) and birches (Betula).<p>In the summer of 2006, Dutchmen on an entomological expedition incidentally observed a pair of nuthatches nesting in the Altai, more or less on the crossing of China, Kazakhstan, Mongolia, and Russia, in a pure larch (Larix sp.) forest at 2,150 m (85,000 in) altitude. They observed that the male had a black crown, the female without black crown, and said that both have a distinct dark eyestripe topped by a white supercilium. If the European nuthatch is present in the region (subspecies asiatica), the observers assure that the black crown of the male and the small size of the individuals exclude a misidentification with this Eurasian species. The closest species geographically that could fit this description is the Chinese nuthatch, which would then be far from its known distribution (1,500 km (930 mi) from the breeding range), and which has more buffy underparts than the observed individuals. To observers, this record could be indicative of a much wider distribution of the Chinese species, or the bird could be an as yet undescribed species related to S. whiteheadi and S. villosa. These two species with distributions 7,000 km (4,300 mi) apart are reminiscent of the case of the two blue magpies of the genus Cyanopica, the azure-winged magpie (C. cyanus) from eastern Asia, and the Iberian magpie (C. cooki) from Portugal and Spain. The exact identity of the Altay breeding pair requires focused research. The history of the discovery and description of the Algerian nuthatch exemplifies how difficult it may be to detect and describe highly isolated populations of nuthatches. In June 2017, during the breeding season, two Swiss ornithologists searched for this nuthatch at the reporting site, staying five nights to prospect in the surrounding forests from the tree line to the valley floor. Three breeding pairs with at least one and two young nuthatches S. europaea asiatica were identified and were the only nuthatch species around. Despite actively looking for food, all the adult nuthatches responded to the species' song replay, and most of the nuthatches were first detected by their call and/or song. The authors conclude that the 2006 sighting was probably of the local Eurasian subspecies, which may have odd-plumaged, or abraded or stained asiatica.

迁徙

Resident species

行为

Migration pattern: Resident species.

保护状况

Population trend: declining.

种群趋势

declining