Thered-billed chough,Cornish chough or simplychough (/ˈtʃʌf/CHUF;Pyrrhocorax pyrrhocorax) is a bird in thecrow family, one of only two species in the genusPyrrhocorax. Its eightsubspecies breed on mountains and coastal cliffs from the western coasts of Ireland and Britain east through southern Europe, North Africa and Middle East 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 spreadprimaries. The red-billed choughpairs for life and displaysfidelity 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 mainlyinvertebrate 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, somelocal extinction and range fragmentation in Europe; however, it is not threatened globally. The red-billed chough, which derived its common name 'chough' from thejackdaw, was formerly associated with fire-raising, and has links with SaintThomas Becket andCornwall.
Taxonomy
The red-billed chough was first described byCarl Linnaeus in his 175810th edition ofSystema Naturae asUpupa pyrrhocorax.[2] It was moved to its current genus,Pyrrhocorax, byMarmaduke Tunstall in his 1771Ornithologia Britannica.[3] The genus name is derived fromGreekπυρρός (pyrrhos), "flame-coloured", andκόραξ (korax), "raven".[4] The only other member of the genus is theAlpine choughPyrrhocorax graculus;[5]hybrids with Alpine chough are known.[6]
Traditionally, the closest relatives of the choughs have been thought to be the typicalcrowsCorvus and thejackdawsColoeus,[7] but more recent genetic studies have suggested the choughs are basal to a group of Asian jay genera (Crypsirina,Dendrocitta,Platysmurus,Temnurus),[8] or most recently, basal in the entire Corvidae.[9]
Subspecies
There are eight extantsubspecies, although differences between them are slight.[10][5]
P. p. erythroramphos, described byLouis Pierre Vieillot in 1817 asCoracia erythrorhamphos,[12] occurs in the red-billed chough's continental European range, excludingGreece. It is larger and slightly greener than the nominate race.[10]
P. p. barbarus, described byCharles Vaurie under its current name in 1954, is resident inNorth Africa and onLa Palma in theCanary Islands. Compared toP. p. erythroramphos, 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.[13]
P. p. baileyi described byAustin Loomer Rand and Charles Vaurie under its current name in 1955,[14] is a dull-plumaged subspecies endemic toEthiopia, where it occurs in two separate areas. The two populations could possibly represent different subspecies.[10]
P. p. docilis, described byJohann Friedrich Gmelin asCorvus docilis in 1774,[15] breeds from Greece toAfghanistan. It is larger than the African subspecies, but it has a smaller bill and its plumage is very green-tinted, with little gloss.[10]
P. p. himalayanus, described byJohn Gould in 1862 asFregilus himalayanus,[16] is found from theHimalayas to western China, butintergrades withP. p. docilis in the west of its range. It is the largest subspecies, long-tailed, and with blue or purple-blue glossed feathers.[10]
P. p. centralis, described byErwin Stresemann in 1928 under its current name,[17] breeds inCentral Asia. It is smaller and less strongly blue thanP. p. himalayanus,[10] but its distinctness from the next subspecies has been questioned.[13]
P. p. brachypus, described byRobert Swinhoe in 1871 asFregilus graculus var.brachypus,[18] breeds in central and northern China, Mongolia and southernSiberia. It is similar toP. p. centralis but with a weaker bill.[10]
The small population inBrittany has often been included with British and Irish birds in the nominate subspeciesP. p. pyrrhocorax, but is now included with other mainland Western European populations inP. p. erythroramphos;[19][5] in some aspects it is intermediate between the two subspecies.[6]
Detailed analysis of call similarity suggests that the Asiatic and Ethiopian races diverged from the western subspecies early inevolutionary history, and that Italian red-billed choughs are more closely allied to the North African subspecies than to those of the rest of Europe.[20]
There is one known prehistoric form of the red-billed chough.P. p. primigenius, asubspecies that lived in Europe during thelast ice age, which was described in 1875 byAlphonse Milne-Edwards from finds in southwest France.[21][22]
Nominate subspeciesP. p. pyrrhocorax in flight inCornwall, UK
Adult of subspeciesP. p. barbarus onLa Palma, Canary Islands
ImmatureP. p. himalayanus at 3,800 metres (12,500 feet) at Tilla Lotani, India
"Chough" was originally an alternativeonomatopoeic name for the jackdawColoeus 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.[23]
The Australianwhite-winged choughCorcorax melanorhamphos, despite its similar shape and habits, is in a separate familyCorcoracidae only moderately related to the Corvidae and not notably to the true choughs, and is an example ofconvergent evolution.[9][5]
Description
The adult of the "nominate" subspecies of the red-billed chough,P. p. pyrrhocorax, is 39–40 centimetres (15–16 inches) in length, has a 73–90 centimetres (29–35 inches) wingspan,[24] and weighs an average 310 grammes (10.9 oz).[4] Its plumage is velvet-black, green-glossed on the body, and it has a long curved red bill and red legs. The sexes are similar (although adults can be sexed in the hand using a formula involvingtarsus length and bill width[25]) but the juvenile has an orange bill and pink legs until its first autumn, and less glossy plumage.[10]
The red-billed chough is unlikely to be confused with any other species of bird. Although the jackdaw and Alpine chough share its range, the jackdaw is smaller and has unglossed grey plumage, and the Alpine chough has a short yellow bill. Even in flight, the two choughs can be distinguished by Alpine's less rectangular wings, and longer, less square-ended tail.[10]
The red-billed chough's loud, ringingchee-ow call is clearer and louder than the similar vocalisation of the jackdaw, and always very different from that of its yellow-billedcongener, which has ripplingpreep and whistledsweeeooo calls.[10] Small subspecies of the red-billed chough have higher frequency calls than larger races, as predicted by the inverse relationship between body size and frequency.[26]
Distribution and habitat
The red-billed chough breeds in Ireland, western Great Britain, the Isle of Man, Brittany, theAlps, La Palma in the Canary Islands, across southern Europe and theMediterranean basin, northern Arabia, northern Iraq, Iran, Afghanistan,[27] and in mountainous country acrossCentral Asia, India and China, with two separate populations in the Ethiopian Highlands. It is anon-migratory resident throughout its range.[10]
Its main habitat is high mountains; it is found between 2,000 and 2,500 metres (6,600 and 8,200 ft) in North Africa, and mainly between 2,400 and 3,000 metres (7,900 and 9,800 ft) in the Himalayas. In that mountain range it reaches 6,000 metres (20,000 feet) in the summer, and has been recorded at 7,950 metres (26,080 feet) altitude onMount Everest.[10] In the British Isles and Brittany it also breeds on coastal sea cliffs, feeding on adjacent short grazed grassland ormachair. It was formerly more widespread on coasts but has suffered from the loss of its specialised habitat.[28][29] It tends to breed at a lower elevation than the Alpine chough,[24] that species having a diet better adapted to high altitudes.[30]
Behaviour and ecology
Breeding
The red-billed chough breeds from three years of age, and normally raises only one brood a year,[4] although the age at first breeding is greater in large populations.[31] A pair exhibits strong mate andsite fidelity once abond is established.[32] The bulky nest is composed of roots and stems ofheather,furze or other plants, and is lined with wool or hair;[24] in central Asia, the hair may be taken from liveHimalayan tahr.[citation needed] The nest is constructed in a cave or similar fissure in a crag or cliff face.[24] In soft sandstone, the birds themselves excavate holes nearly a metre deep.[33] Old buildings may be used, and inTibet working monasteries provide sites, as occasionally do modern buildings inMongolian towns, includingUlaanbaatar.[10] The red-billed chough will utilise other artificial sites, such as quarries and mineshafts for nesting where they are available.[34]
The chough lays three to five eggs 3.9 by 2.8 centimetres (1.5 by 1.1 inches) in size and weighing 15.7 grammes (0.55 oz), of which 6% is shell.[4] They are spotted, not always densely, in various shades of brown and grey on a creamy or slightly tinted ground.[24]The egg size is independent of the clutch size and the nest site, but may vary between different females.[35] The femaleincubates for 17–18 days before thealtricial downy chicks are hatched, and is fed at the nest by the male. The femalebroods the newly hatched chicks for around ten days,[36] and then both parents share feeding and nest sanitation duties. The chicksfledge 31–41 days after hatching.[4]
Juveniles have a 43% chance of surviving their first year, and the annual survival rate of adults is about 80%. Choughs generally have a lifespan of about seven years,[4] although an age of 17 years has been recorded.[32] The temperature and rainfall in the months preceding breeding correlates with the number of young fledging each year and their survival rate. Chicks fledging under good conditions are more likely to survive to breeding age, and have longer breeding lives than those fledging under poor conditions.[31]
Feeding
The long curved bill is used to dig for invertebrates and bulbs.
The red-billed chough's food consists largely of insects, spiders and otherinvertebrates taken from the ground, withants probably being the most significant item.[10] The Central Asian subspeciesP. p. centralis will perch on the backs of wild or domesticatedmammals to feed on parasites.[citation needed] Although invertebrates make up most of the chough's diet, it will eat vegetable matter including fallen grain, and in the Himalayas has been reported as damagingbarley crops by breaking off the ripening heads to extract the corn.[10] In the Himalayas, they form large flocks in winter.[37]
The preferred feeding habitat is short grass produced by grazing, for example by sheep and rabbits, the numbers of which are linked to the chough's breeding success. Suitable feeding areas can also arise where plant growth is hindered by exposure to coastal salt spray or poor soils.[38][39] It will use its long curved bill to pick ants,dung beetles and emerging flies off the surface, or to dig for grubs and other invertebrates. The typical excavation depth of 2–3 cm (3⁄4–1+1⁄4 in) reflects the thin soils which it feeds on, and the depths at which many invertebrates occur, but it may dig to 10–20 cm (4–8 in) in appropriate conditions.[40][41]
Where the two chough species occur together, there is only limited competition for food. An Italian study showed that the vegetable part of the winter diet for the red-billed chough was almost exclusivelyGagea bulbs, whilst the Alpine chough took berries and hips. In June, red-billed choughs fed onLepidopteralarvae whereas Alpine choughs atecraneflypupae. Later in the summer, the Alpine chough mainly consumedgrasshoppers, whilst the red-billed chough added cranefly pupae,fly larvae and beetles to its diet.[30] Both choughs will hide food in cracks and fissures, concealing the cache with a few pebbles.[42]
Natural threats
Red-billed chough (left) can be distinguished from Alpine chough in flight by its deeper primary "fingers" and tail wedge. Its wings extend further, to or beyond the tail tip, when it is standing.
The red-billed chough's predators include theperegrine falcon,golden eagle andEurasian eagle-owl, while thecommon raven will take nestlings.[43][44][45][46] In northernSpain, red-billed choughs preferentially nest nearlesser kestrel colonies. This smallinsectivorousfalcon is better at detecting a predator and more vigorous in defence than itscorvid neighbours. The breeding success of the red-billed chough in the vicinity of the kestrels was found to be much higher than that of birds elsewhere, with a lower percentage of nest failures (16% near the falcon, 65% elsewhere).[46]
This species is occasionallyparasitised by thegreat spotted cuckoo, abrood parasite for which theEurasian magpie is the primary host.[47]Red-billed choughs can acquire blood parasites such asPlasmodium, but a study in Spain showed that the prevalence was less than one percent, and unlikely to affect the life history and conservation of this species.[48] These low levels of parasitism contrast with a much higher prevalence in some other passerine groups; for example a study ofthrushes in Russia showed thatall thefieldfares,redwings andsong thrushes sampled carried haematozoans, particularlyHaemoproteus andTrypanosoma.[49]
Red-billed choughs can also carrymites, but a study of the feather miteGabucinia delibata, acquired by young birds a few months after fledging when they join communal roosts, suggested that this parasite actuallyimproved the body condition of its host. It is possible that the feather mites enhance feather cleaning and deterpathogens,[50] and may complement other feather care measures such as sunbathing, andanting—rubbing the plumage with ants (theformic acid from the insects deters parasites).[10]
Status
The red-billed chough has an extensive range, estimated at ten million square kilometres (four million square miles), and a large population, including an estimated 86,000 to 210,000 individuals in Europe. Over its range as a whole, the species is not believed to approach the thresholds for the global population decline criterion of theIUCN Red List (i.e., declining more than 30% in ten years or three generations), and is therefore evaluated asleast concern.[1]
However, the European range has declined and fragmented due to the loss of traditional pastoral farming, persecution and perhaps disturbance at breeding and nesting sites, although the numbers inFrance, Great Britain and Ireland may now have stabilised.[24] The European breeding population is between 12,265 and 17,370 pairs, but only in Spain is the species still widespread. Since in the rest of the continent breeding areas are fragmented and isolated, the red-billed chough has been categorised as "vulnerable" in Europe.[34]
In Spain the red-billed chough has recently expanded its range by utilising old buildings, with 1,175 breeding pairs in a 9,716-square-kilometre (3,751 sq mi) study area. These new breeding areas usually surround the original montane core areas. However, the populations with nest sites on buildings are threatened by human disturbance, persecution and the loss of old buildings.[51] Fossils of both chough species were found in the mountains of theCanary 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.[52]
A small group of wild red-billed chough arrived naturally inCornwall in 2001, and nested in the following year. This was the first English breeding record since 1947, and a slowly expanding population has bred every subsequent year.[29] The Chough Reintroduction Project, a partnership betweenKent Wildlife Trust, Wildwood Trust andParadise Park, Cornwall, reintroduced the red-billed chough toSouth East England where it had previously been extinct for over two centuries.[53] The first of several releases took place at a secret location inDover in July 2023, releasing eight choughs which came from a zoo-based breeding programme coordinated by Paradise Park in Cornwall.[54] By October 2023, the released choughs had been spotted flying as far asDover Castle.[55] In May 2024, the first wild red-billed chough chick to be born in Kent for generations was discovered at Dover Castle and was reported to have fledged successfully the following month, but went missing during strong winds in early July. A second release of six female choughs into the wild took place in July 2024.[56] By September 2024 an additional six male choughs had been released into the wild, increasing the total number of wild red-billed chough in Kent to nineteen animals.[57]
InJersey, theDurrell Wildlife Conservation Trust, in partnership with theStates of Jersey and theNational Trust for Jersey began a project in 2010, aimed at restoring selected areas of Jersey's coastline with the intention of returning those birds that had become locally extinct. The red-billed chough was chosen as a flagship species for this project, having been absent from Jersey since around 1900. Durrell initially received two pairs of choughs fromParadise Park in Cornwall and began acaptive breeding programme.[58] In 2013, juveniles were released onto the north coast of Jersey using soft-release methods developed at Durrell. Over the next five years, small cohorts of captive-bred choughs were released, monitored, and provided supplemental food.[59]
Arms ofCardinal Thomas Wolsey (d.1530),Archbishop of York:Sable, on a cross engrailed argent a lion passant gules between four leopard's faces azure; on a chief or a rose gules barbed vert seeded or between two Cornish choughs proper
A yellow flag featuring a Cornish chough was used by theNewquay unit of the CornwallHome Guard duringWorld War II (the unit's nickname was "The Choughs")[60][61][62]
Greek mythology
InGreek mythology, the red-billed chough, also known as 'sea-crow', was considered sacred to theTitanCronus and dwelt onOgygia,Calypso's 'Blessed Island',[63] where "The birds of broadest wing their mansions form/The chough, the sea-mew, the loquacious crow."[64]
Cornish heraldry
The red-billed chough has a long association with Cornwall, and appears on the Cornishcoat of arms.[11] According to Cornish legendKing Arthur did not die after his last battle but rather his soul migrated into the body of a red-billed chough, the red colour of its bill and legs being derived from the blood of the last battle[65] and hence killing this bird was unlucky.[63] Legend also holds that after the last Cornish chough departs from Cornwall, then the return of the chough, as happened in 2001, will mark the return of King Arthur.[66]
In Englishheraldry the bird is alwaysblazoned as "a Cornish chough" and is usually shown "proper", withtinctures as in nature. Since the 14th century, StThomas Becket (d.1170),Archbishop of Canterbury, has retrospectively acquired anattributed coat of arms consisting of three Cornish choughs on a white field,[67] although as he died 30 to 45 years before the start of the age of heraldry,[68] in reality he bore no arms. These attributed arms appear in many English churches dedicated to him. The symbolism behind the association is not known for certain. According to one legend, a chough strayed intoCanterbury Cathedral during Becket's murder, while another suggests that the choughs are acanting reference to Becket's name, as they were once known as "beckits".[69] However the latter theory does not stand up to scrutiny, as the use of the term "beckit" to mean a chough is not found before the 19th century.[69] Regardless of its origin, the chough is still used in heraldry as a symbol of Becket, and appears in the arms of several persons and institutions associated with him, most notably in the arms of the city ofCanterbury.[70]
Nuisance species
Up to the eighteenth century, the red-billed chough was associated withfire-raising, and was described byWilliam Camden asincendaria avis, "oftentime it secretly conveieth fire sticks, setting their houses afire".[23]Daniel Defoe was also familiar with this story:
It is counted little better than a kite, for it is of ravenous quality, and is very mischievous; it will steal and carry away any thing it finds about the house, that is not too heavy, tho' not fit for its food; as knives, forks, spoons and linnen cloths, or whatever it can fly away with, sometimes they say it has stolen bits of firebrands, or lighted candles, and lodged them in the stacks of corn, and the thatch of barns and houses, and set them on fire; but this I only had by oral tradition.[71]
Not all mentions of "chough" refer to this species. Because of the origins of its name, whenShakespeare writes of "the crows and choughs that wing the midway air" [King Lear, act 4, scene 6] orHenry VIII'sVermin Act 1532 is "ordeyned to dystroye Choughes, Crowes and Rookes", they are clearly referring to thejackdaw.[23]
Other symbolism
The red-billed chough has been depicted on postage stamps of a few countries, including theIsle of Man, with four different stamps,Bhutan,Turkmenistan,Yugoslavia, andThe Gambia, where the bird does not occur.[72] It is the animal symbol of the island ofLa Palma.[73]
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^Tunstall, Marmaduke (1771).Ornithologia Britannica: seu Avium omnium Britannicarum tam terrestrium, quam aquaticarum catalogus, sermone Latino, Anglico et Gallico redditus (in Latin). London, J. Dixwell. p. 2.
^abShirihai, Hadoram; Svensson, Lars (2019).Handbook of Western Palearctic birds. volume 2: Passerines: flycatchers to buntings. London Oxford New York New Delhi Sydney: Helm.ISBN978-1-4729-3737-7.
^Goodwin, Derek; Gillmor, Robert (1976).Crows of the World. London: British Museum (Natural History). p. 151.ISBN0-565-00771-8.
^abFjeldså, Jon; Christidis, Les; Ericson, Per G. P. (2020).The Largest Avian Radiation. Barcelona: Lynx edicions.ISBN978-84-16728-33-6.
^abcdefghijklmnopqMadge, Steve; Burn, Hilary (1994).Crows and jays: a guide to the crows, jays and magpies of the world. A&C Black. pp. 133–5.ISBN0-7136-3999-7.
^Stresemann, Erwin (1928). "Die Vögel der Elburs Expedition 1927".Journal of Ornithology (in German).76 (2):313–326.doi:10.1007/BF01940684.S2CID27450092.
^Swinhoe, Robert (1871). "A revised catalogue of the birds of China and its islands, with descriptions of new species, references to former notes, and occasional remarks".Proceedings of the Zoological Society of London: 383.
^Mourer-Chauviré, Cécile (1975). "Les oiseaux du Pléistocène moyen et supérieur de France".Documents des Laboratoires de Géologie de la Faculté des Sciences de Lyon (in French).64.
^abcdefSnow, David; Perrins, Christopher M., eds. (1998).The Birds of the Western Palearctic concise edition (2 volumes). Oxford: Oxford University Press.ISBN0-19-854099-X. 1466–68
^abRolando, A; Laiolo, P (April 1997). "A comparative analysis of the diets of the choughPyrrhocorax pyrrhocorax and the alpine choughPyrrhocorax graculus coexisting in the Alps".Ibis.139 (2):388–395.doi:10.1111/j.1474-919X.1997.tb04639.x.
^abRoberts, P. J. (1985). "The choughs of Bardsey".British Birds.78 (5):217–32.
^Ali, Salim; Ripley, S Dillon (1986).Handbook of the birds of India and Pakistan. Vol. 5 (2nd ed.). Oxford University Press. pp. 239–242.ISBN0-19-562063-1.
^Laiolo, P.; Bignal, E.M.; Patterson, I.J. (1998). "The dynamics of parental care in Choughs (Pyrrhocorax pyrrhocorax)".Journal of Ornithology.139 (3):297–305.doi:10.1007/BF01653340.S2CID42610400.
^Rasmussen, Pamela C.; Anderson, John C. (2005).Birds of South Asia. The Ripley Guide. Volume 2. Smithsonian Institution and Lynx Edicions. pp. 597–598.
^Rolando, Antonio; Caldoni, Riccardo; De Sanctis, Augusto; Laiolo, Paola (2001). "Vigilance and neighbour distance in foraging flocks of red-billed choughs,Pyrrhocorax pyrrhocorax".Journal of Zoology.253 (2):225–232.doi:10.1017/S095283690100019X.
^Palinauskas, Vaidas; Markovets, Mikhail Yu; Kosarev, Vladislav V; Efremov, Vladislav D; Sokolov Leonid V; Valkiûnas, Gediminas (2005). "Occurrence of avian haematozoa in Ekaterinburg and Irkutsk districts of Russia".Ekologija.4:8–12.
^"Red-billed Chough". Durrell Wildlife Conservation Trust. Archived fromthe original on 27 September 2021. Retrieved15 July 2019.
^"Choughs: Field Programme".Birds on the Edge. Durrell Wildlife Conservation Trust.Archived from the original on 23 December 2018. Retrieved15 July 2019.
^Newlyn, Lucy (2005).Chatter of Choughs: An Anthology Celebrating the Return of Cornwall's Legendary Bird. Wilkinson, Lucy (illustrator). Hypatia Publications. p. 31.ISBN1-872229-49-2.
![A yellow flag featuring a Cornish chough was used by the Newquay unit of the Cornwall Home Guard during World War II (the unit's nickname was "The Choughs")[60][61][62]](/mt/?noimg=&dark=on&url=http%3a%2f%2fen.wikipedia.org%2fwiki%2fFile%3aFlag_of_the_Newquay_Battalion_of_the_Cornwall_Home_Guard.svg)
