The red-billed chough, Cornish chough or simply chough ( ; Pyrrhocorax pyrrhocorax), is a bird in the crow family, one of only two species in the genus Pyrrhocorax. Its eight subspecies breed on mountains and coastal cliffs from the western coasts of Ireland and Britain east through southern Europe and North Africa to Central Asia, India and China.
This bird has glossy black plumage, a long curved red bill, red legs, and a loud, ringing call. It has a buoyant acrobatic flight with widely spread primaries. The red-billed 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 wool-lined stick nest and lays three eggs. It feeds, often in flocks, on short grazed grassland, taking mainly invertebrate prey.
Although it is subject to predation and parasitism, the main threat to this species is changes in agricultural practices, which have led to population decline, some local extirpation, and range fragmentation in Europe; however, it is not threatened globally. The red-billed chough, which derived its common name from the jackdaw, was formerly associated with fire-raising, and has links with Saint Thomas Becket and Cornwall. The red-billed chough has been depicted on postage stamps of a few countries, including the Isle of Man, with four different stamps, and the Gambia, where the bird does not occur.
Taxonomy
The red-billed chough was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae as Upupa pyrrhocorax. It was moved to its current genus, Pyrrhocorax, by Marmaduke Tunstall in his 1771 Ornithologia Britannica. The genus name is derived from Greek πυρρός (pyrrhos), "flame-coloured", and κόραξ (korax), "raven". The only other member of the genus is the Alpine chough, Pyrrhocorax graculus. The closest relatives of the choughs are the typical crows, Corvus, especially the jackdaws in the subgenus Coloeus.
"Chough" was originally an alternative onomatopoeic name for the jackdaw, Corvus monedula, based on its call. The similar red-billed species, formerly particularly common in Cornwall, became known initially as "Cornish chough" and then just "chough", the name transferring from one species to the other. The Australian white-winged chough, Corcorax melanorhamphos, despite its similar shape and habits, is only distantly related to the true choughs, and is an example of convergent evolution.
Subspecies
There are eight extant subspecies, although differences between them are slight. P. p. pyrrhocorax, the nominate subspecies and smallest form, is endemic to the British Isles, where it is restricted to Ireland, the Isle of Man, and the far west of Wales and Scotland, although it recolonised Cornwall in 2001 after an absence of 50 years. P. p. erythropthalmus, described by Louis Jean Pierre Vieillot in 1817 as Coracia erythrorhamphos, occurs in the red-billed chough's continental European range, excluding Greece. It is larger and slightly greener than the nominate race. P. p. barbarus, described by Charles Vaurie under its current name in 1954, is resident in North Africa and on La Palma in the Canary Islands. Compared to P. p. erythropthalmus, it is larger, has a longer tail and wings, and its plumage has a greener gloss. It is the longest-billed form, both absolutely and relatively. P. p. baileyi described by Austin Loomer Rand and Charles Vaurie under its current name in 1955, is a dull-plumaged subspecies endemic to Ethiopia, where it occurs in two separate areas. The two populations could possibly represent different subspecies. P. p. docilis, described by Johann Friedrich Gmelin as Corvus docilis in 1774, breeds from Greece to Afghanistan. It is larger than the African subspecies, but it has a smaller bill and its plumage is very green-tinted, with little gloss.
P. p. himalayanus, described by John Gould in 1862 as Fregilus himalayanus, is found from the Himalayas to western China, but intergrades with P. p. docilis in the west of its range. It is the largest subspecies, long-tailed, and with blue or purple-blue glossed feathers. P. p. centralis, described by Erwin Stresemann in 1928 under its current name, breeds in Central Asia. It is smaller and less strongly blue than P. p. himalayanus, but its distinctness from the next subspecies has been questioned. P. p. brachypus, described by Robert Swinhoe in 1871 as Fregilus graculus var. brachypus, breeds in central and northern China, Mongolia and southern Siberia. It is similar to P. p. centralis but with a weaker bill.