About Pyrrhocorax pyrrhocorax (Linnaeus, 1758)
For the nominate subspecies of the red-billed chough, Pyrrhocorax pyrrhocorax pyrrhocorax, adult individuals measure 39–40 centimetres (15–16 inches) in length, have a 73–90 centimetre (29–35 inch) wingspan, and average 310 grammes (10.9 oz) in weight. This subspecies has velvet-black plumage with green gloss on the body, a long curved red bill, and red legs. Male and female red-billed choughs have similar outward appearance, though adults can be sexed when handled via a formula that uses tarsus length and bill width. Juveniles have orange bills, pink legs until their first autumn, and less glossy plumage than adults. The red-billed chough is not easily confused with any other bird species. While it shares its range with the western jackdaw and the Alpine chough, the jackdaw is smaller and has unglossed grey plumage, and the Alpine chough has a short yellow bill. Even in flight, the two chough species can be told apart: the Alpine chough has less rectangular wings, and a longer, less square-ended tail than the red-billed chough. The red-billed chough produces a loud, ringing chee-ow call that is clearer and louder than the similar call of the jackdaw, and very different from the calls of the yellow-billed Alpine chough, which are a rippling preep and a whistled sweeeooo. As expected from the inverse relationship between body size and call frequency, smaller red-billed chough subspecies have higher frequency calls than larger subspecies. The red-billed chough breeds across Ireland, western Great Britain, the Isle of Man, Brittany, the Alps, La Palma in the Canary Islands, southern Europe, the Mediterranean basin, northern Arabia, northern Iraq, Iran, Afghanistan, mountainous regions of Central Asia, India, and China, with two distinct isolated populations in the Ethiopian Highlands. It is a non-migratory resident that stays within its range year-round. Its primary habitat is high mountains. In North Africa, it occurs between 2,000 and 2,500 metres (6,600 and 8,200 ft), and mainly between 2,400 and 3,000 metres (7,900 and 9,800 ft) in the Himalayas. In the Himalayas, it can reach 6,000 metres (20,000 feet) in elevation in summer, and has been recorded at 7,950 metres (26,080 feet) on Mount Everest. In the British Isles and Brittany, the red-billed chough also breeds on coastal sea cliffs, foraging on nearby short grazed grassland or machair. It was formerly more widespread across coastal areas, but has declined due to loss of this specialised habitat. The red-billed chough generally breeds at lower elevations than the Alpine chough, as the Alpine chough has a diet better suited to high altitudes.
