Альпийская галка: описание и распространение.

Bird in the crow family

The Alpine chough ('/tʃ//ʌ//f/) or yellow billed chough (Pyrrhocorax graculus) is a bird in the crow family, one of only two species in the genus Pyrrhocorax. Its two subspecies breed in high mountains from Spain eastwards through southern Europe and North Africa to Central Asia and Nepal, and it may nest at a higher altitude than any other bird. The eggs have adaptations to the thin atmosphere that improve oxygen take up and reduce water loss. This bird has glossy black plumage, a yellow beak, red legs, and distinctive calls. It has a buoyant acrobatic flight with widely spread flight feathers. The Alpine chough pairs for life and displays fidelity to its breeding site, which is usually a cave or crevice in a cliff face. It builds a lined stick nest and lays three to five brown blotched whitish eggs. It feeds, usually in flocks, on short grazed grassland, taking mainly invertebrate prey in summer and fruit in winter; it will readily approach tourist sites to find supplementary food. Although it is subject to predation and parasitism, and changes in agricultural practices have caused local population declines, this widespread and abundant species is not threatened globally. Climate change may present a long term threat, by shifting the necessary Alpine habitat to higher altitudes.

The Alpine chough was first described as Corvus graculus by Linnaeus in the Systema Naturae in 1766. It was moved to its current genus, Pyrrhocorax, by English ornithologist Marmaduke Tunstall in his 1771 Ornithologia Britannica, along with the only other member of the genus, the red billed chough, P. pyrrhocorax. The closest relatives of the choughs were formerly thought to be the typical crows, Corvus, especially the jackdaws in the subgenus Coloeus, but DNA and cytochrome b analysis shows that the genus Pyrrhocorax, along with the ratchet tailed treepie (genus Temnurus), diverged early from the rest of the Corvidae. The genus name is derived from Greek πύρρος (purrhos), "flame coloured", and κόραξ (korax), "raven". The species epithet graculus is Latin for a jackdaw. The current binomial name of the Alpine chough was formerly sometimes applied to the red billed chough. The English word "chough" was originally an alternative onomatopoeic name for the jackdaw, Corvus monedula, based on its call. The red billed chough, formerly particularly common in Cornwall and known initially as the "Cornish chough", eventually became just "chough", the name transferring from one genus to another. The Alpine chough has two extant subspecies. P. g. graculus, the nominate subspecies in Europe, north Africa, Turkey, the Caucasus and northern Iran. is larger and has stronger feet than the nominate race. but this has not been widely accepted and is usually treated as synonymous with digitatus. A Pleistocene form from Europe was similar to the extant subspecies, and is sometimes categorised as P. g. vetus. The Australian white winged chough, Corcorax melanorhamphos, despite its similar bill shape and black plumage, is only distantly related to the true choughs.

The adult of the nominate subspecies of the Alpine chough has glossy black plumage, a short yellow bill, dark brown irises, and red legs. The sexes are identical in appearance, although the male averages slightly larger than the female. The juvenile is duller than the adult, with a dull yellow bill and brownish legs. The flight of the Alpine chough is swift and acrobatic with loose, deep wing beats. Its high manoeuvrability is accomplished by fanning the tail, folding its wings, and soaring in the updraughts at cliff faces. Even in flight, it can be distinguished from the red billed chough by its less rectangular wings, and longer, less square ended tail. The rippling and whistled calls of the Alpine chough are quite different from the more typically crow like vocalisations of the jackdaw and the red billed chough. It also has a rolling alarm call, and a variety of quiet warbles and squeaks given by resting or feeding birds.

The Alpine chough breeds in mountains from Spain eastwards through southern Europe and the Alps across Central Asia and the Himalayas to western China. There are also populations in Morocco, Corsica and Crete. It is a non migratory resident throughout its range, although Moroccan birds have established a small colony near Málaga in southern Spain, and wanderers have reached Czechoslovakia, Gibraltar, Hungary and Cyprus. surpassing even the red billed chough, which has a diet less well adapted to the highest altitudes. It usually nests in cavities and fissures on inaccessible rock faces, although locally it will use holes between rocks in fields, and forages in open habitats such as alpine meadows and scree slopes to the tree line or lower, and in winter will often congregate around human settlements, ski resorts, hotels and other tourist facilities. Nesting typically starts in early May, and is non colonial, although in suitable habitat several pairs may nest in close proximity. which are tinged with buff, cream or light green and marked with small brown blotches; — and fledge 29–31 days from hatching. The embryos of bird species that breed at high altitude also have haemoglobin with a genetically determined high affinity for oxygen. In the western Italian Alps, the Alpine chough nests in a greater variety of sites than red billed chough, using natural cliffs, pot holes and abandoned buildings, whereas the red billed uses only natural cliffs (although it nests in old buildings elsewhere). The Alpine chough lays its eggs about one month later than its relative, although breeding success and reproductive behaviour are similar. The similarities between the two species presumably arose because of the same strong environmental constraints on breeding behaviour. The chough will readily supplement its winter diet with food provided by tourist activities in mountain regions, including ski resorts, refuse dumps and picnic areas. Where additional food is available, winter flocks are larger and contain a high proportion of immature birds. The young birds principally frequent the sites with the greatest food availability, such as refuse dumps. Both chough species will hide food in cracks and fissures, concealing the cache with a few pebbles. This bird always forages in groups, which are larger in winter than summer, and have constant composition in each season. Where food resources are restricted, adults dominate young birds, and males outrank females. Feeding trips may cover distance and in altitude. In the Alps, the development of skiing above has enabled more birds to remain at high levels in winter. In the eastern Himalayas in November, Alpine choughs occur mainly in juniper forests where they feed on juniper berries, differing ecologically from the red billed choughs in the same region and at the same time of year, which feed by digging in the soil of terraced pastures of villages.

Predators of the choughs include the peregrine falcon, golden eagle and Eurasian eagle owl, while the common raven will take nestlings. Alpine choughs have been observed diving at a Tibetan red fox. It seems likely that this "mobbing" behaviour may be play activity to give practice for when genuine defensive measures may be needed to protect eggs or young. The Alpine chough is a host of the widespread bird flea Ceratophyllus vagabunda, two specialist chough fleas Frontopsylla frontalis and F. laetus, a cestode Choanotaenia pirinica, and various species of chewing lice in the genera Brueelia, Menacanthus and Philopterus.

The Alpine chough has an extensive though sometimes fragmented range, estimated at 1–10 million square kilometres (0.4–3.8 million sq mi), and a large population, including an estimated 260,000 to 620,000 individuals in Europe. The Corsican population has been estimated to comprise about 2,500 birds. Over its range as a whole, the species is not believed to approach the thresholds for the global population decline criteria of the IUCN Red List (i. e., declining more than 30% in ten years or three generations), and is therefore evaluated as Least Concern. Some of these peripheral prehistoric populations persisted until recently, only to disappear within the last couple of centuries. In the Polish Tatra Mountains, where a population had survived since the glacial period, it was not found as a breeding bird after the 19th century. In Bulgaria, the number of breeding sites fell from 77 between 1950 and 1981 to just 14 in the 1996 to 2006 period, and the number of pairs in the remaining colonies were much smaller. The decline was thought to be due to the loss of former open grasslands which had reverted to scrubby vegetation once extensive cattle grazing ceased. Foraging habitat can also be lost to human activities such as the construction of ski resorts and other tourist development on former alpine meadows. Populations of choughs are stable or increasing in areas where traditional pastoral or other low intensity agriculture persists, but are declining or have become locally extinct where intensive farming methods have been introduced, such as Brittany, England, south west Portugal and mainland Scotland. Choughs can be locally threatened by the accumulation of pesticides and heavy metals in the mountain soils, heavy rain, shooting and other human disturbances, Fossils of both chough species were found in the mountains of the Canary Islands. The local extinction of the Alpine chough and the reduced range of red billed chough in the islands may have been due to climate change or human activity.