Alpine Chough
Encyclopedia
The Alpine Chough 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
east through southern Europe and North Africa
to Central Asia
, India and China, 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 bill, red legs, and distinctive calls. It has a buoyant acrobatic flight with widely spread flight feather
s. 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 crow
s, 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.
Moravia
n palaeontologist
Ferdinand Stoliczka
separated the Himalayan population as a third subspecies, P. g. forsythi, but this has not been widely accepted and is usually treated as synonym
ous with digitatus. A Pleistocene
form from Europe was similar to the extant subspecies, and is sometimes categorised as P. g. vetus.
The Australia
n 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. It is slightly smaller than Red-billed Chough, at 37–39 centimetres (14.6–15.3 in) length with a 12–14 cm (4.7–5.5 in) tail and a 75–85 cm (29.5–33.5 in) wingspan, but has a proportionally longer tail and shorter wings than its relative. It has a similar buoyant and easy flight. 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 Alpine Chough is unlikely to be confused with any other species; although the Jackdaw and Red-billed Chough share its range, the Jackdaw is smaller and has unglossed grey plumage, and the Red-billed Chough has a long red bill.
The subspecies P. g. digitatus averages slightly larger than the nominate form, weighing 191–244 grams (6.8–8.7 oz) against 188–252 g (6.7–9.0 oz) for P. g. graculus, and it has stronger feet. This is in accordance with Bergmann's rule
, which predicts that the largest birds should be found higher elevations or in colder and more arid regions. The extremities of the body, the bill and tarsus
, were longer in warmer areas, in line with Allen's rule
. Temperature seemed to be the most important cause of body variation in the Alpine Chough.
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 Red-billed Chough by its less rectangular wings, and longer, less square-ended tail.
The rippling
preep and whistled sweeeooo calls of the Alpine Chough are quite different from the more typically crow-like
chee-ow vocalisations of the Jackdaw and the Red-billed Chough. It also has a rolling churr alarm call, and a variety of quiet warbles and squeaks given by resting or feeding birds. In a study of chough calls throughout the Palearctic region it was found that call frequencies
in the Alpine Chough showed an inverse relationship
between body size and frequency, being higher-pitched in smaller-bodied populations.
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
.
This is a high-altitude species normally breeding between 1260–2880 m (4,133.9–9,448.8 ft) in Europe, 2880–3900 m (9,448.8–12,795.3 ft) in Morocco, and 3500–5000 m (11,482.9–16,404.2 ft) in the Himalayas. It has nested at 6500 m (21,325.5 ft), higher than any other bird species, even surpassing the Red-billed Chough which has a diet less well adapted to the highest altitudes. It has been observed following mountaineers ascending Mount Everest
at an altitude of 8200 m (26,902.9 ft). 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 slope
s to the tree line or lower, and in winter will often congregate around human settlements, ski resort
s, hotels and other tourist facilities. Its penchant for waiting by hotel windows for food is popular with tourists, but less so with hotel owners.
The Alpine Chough is socially monogamous
, showing high partner fidelity in summer and winter and from year to year. Nesting typically starts in early May, and is non-colonial, although in suitable habitat several pairs may nest in close proximity. The bulky nests are composed of roots, sticks and plant stems lined with grass, fine twiglets or hair, and may be constructed on ledges, in a cave or similar fissure in a cliff face, or in an abandoned building. The clutch
is 3–5 glossy whitish eggs, averaging 33.9 by 24.9 mm (1.3 by 0.980314960629921 in) in size, which are tinged with buff, cream or light-green and marked with small brown blotches; they are incubated by the female for 14–21 days before hatching. The chicks hatch with a dense covering of natal down
, in contrast to those of the Red-billed Chough which are almost naked, and fledge
in a further 29–31 days from hatching. The young birds are fed by both parents, and may also be fed by other adults when they have fledged and joined the flock. Breeding is possible in the high mountains because chough eggs have relatively fewer pores than those of lowland species, and lose less water by evaporation at low atmospheric pressure. The embryo
s 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.
A study of three different European populations showed a mean clutch size of 3.6 eggs, producing 2.6 chicks, of which 1.9 fledged. Adult survival rate varied from 83 to 92%, with no significant difference detected between males and females. Survival of first-year birds was, at 77%, lower than that of adults. The availability or otherwise of human food supplied from tourist activities did not affect breeding success.
s collected from pasture, such as beetle
s (Selatosomus aeneus
and Otiorhynchus morio
have been recorded from pellets
), snail
s, grasshopper
s, caterpillar
s and fly
larva
e. The diet in autumn, winter and early spring becomes mainly fruit, including berries
such as the European Hackberry (Celtis australis
) and Sea-buckthorn (Hippophae rhamnoides
), rose hip
s, and domesticated crops such as apples, grapes and pears where available. It has been observed eating flowers of Crocus vernus albiflorus
, including the pistils
, perhaps as a source of carotenoid
s. The chough will readily supplement its winter diet with food provided by tourist activities in mountain regions, including ski resorts, refuse dump
s 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. Foraging areas change altitudinally through the year, depending on climatic factors, food availability and food quality. During the breeding season, birds remain above the tree line, although they may use food provided by tourists at refuges and picnic areas.
Movement to lower levels begins after the first snowfalls, and feeding by day is mainly in or near valley bottoms when the snow cover deepens, although the birds return to the mountains to roost. In March and April the choughs frequent villages at valley tops or forage in snow-free patches prior to their return to the high meadows. Feeding trips may cover 20 km (12.4 mi) distance and 1600 m (5,249.3 ft) in altitude. In the Alps, the development of skiing above 3000 m (9,842.5 ft) has enabled more birds to remain at high levels in winter.
Where their ranges overlap, the two chough species may feed together in the summer, although 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 exclusively Gagea
bulbs dug from the ground, whilst the Alpine Chough took berries and hips. In June, Red-billed Choughs fed mainly on caterpillars whereas Alpine Choughs ate crane fly
pupa
e. Later in the summer, the Alpine Chough consumed large numbers of grasshoppers, while the Red-billed Chough added cranefly pupae, fly larvae and beetles to its diet. 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.
, 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.
.
At the greatest extent of the last glacial period around 18,000 years ago, southern Europe was characterised by cold open habitats, and the Alpine Chough was found as far as south as southern Italy, well outside its current range. 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 pesticide
s and heavy metals in the mountain soils, heavy rain, shooting and other human disturbances, but a longer-term threat comes from global warming
, which would cause the species' preferred Alpine climate
zone to shift to higher, more restricted areas, or locally to disappear entirely. 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.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
in the crow
Crow
Crows form the genus Corvus in the family Corvidae. Ranging in size from the relatively small pigeon-size jackdaws to the Common Raven of the Holarctic region and Thick-billed Raven of the highlands of Ethiopia, the 40 or so members of this genus occur on all temperate continents and several...
family, one of only two species in the genus Pyrrhocorax. Its two subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
breed in high mountains from Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
east through southern Europe and North Africa
North Africa
North Africa or Northern Africa is the northernmost region of the African continent, linked by the Sahara to Sub-Saharan Africa. Geopolitically, the United Nations definition of Northern Africa includes eight countries or territories; Algeria, Egypt, Libya, Morocco, South Sudan, Sudan, Tunisia, and...
to Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...
, India and China, 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
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
, a yellow bill, red legs, and distinctive calls. It has a buoyant acrobatic flight with widely spread flight feather
Flight feather
Flight feathers are the long, stiff, asymmetrically shaped, but symmetrically paired feathers on the wings or tail of a bird; those on the wings are called remiges while those on the tail are called rectrices . Their primary function is to aid in the generation of both thrust and lift, thereby...
s. The Alpine Chough pairs
Pair bond
In biology, a pair bond is the strong affinity that develops in some species between the males and females in a pair, potentially leading to breeding. Pair-bonding is a term coined in the 1940s that is frequently used in sociobiology and evolutionary psychology circles...
for life and displays fidelity
Philopatry
Broadly, philopatry is the behaviour of remaining in, or returning to, an individual's birthplace. More specifically, in ecology philopatry is the behaviour of elder offspring sharing the parental burden in the upbringing of their siblings, a classic example of kin selection...
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
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
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.
Taxonomy
Systema Naturae
The book was one of the major works of the Swedish botanist, zoologist and physician Carolus Linnaeus. The first edition was published in 1735...
in 1766. It was moved to its current genus, Pyrrhocorax, by English ornithologist
Ornithology
Ornithology is a branch of zoology that concerns the study of birds. Several aspects of ornithology differ from related disciplines, due partly to the high visibility and the aesthetic appeal of birds...
Marmaduke Tunstall
Marmaduke Tunstall
Marmaduke Tunstall was an English ornithologist and collector. He was the author of Ornithologica Britannica , probably the first British work to use binomial nomenclature....
in his 1771 Ornithologia Britannica, along with the only other member of the genus, the Red-billed Chough
Red-billed Chough
The Red-billed Chough or Chough , Pyrrhocorax pyrrhocorax, is a bird in the crow family; it is one of only two species in the genus Pyrrhocorax...
, P. pyrrhocorax. The closest relatives of the choughs were formerly thought to be the typical crow
Crow
Crows form the genus Corvus in the family Corvidae. Ranging in size from the relatively small pigeon-size jackdaws to the Common Raven of the Holarctic region and Thick-billed Raven of the highlands of Ethiopia, the 40 or so members of this genus occur on all temperate continents and several...
s, Corvus, especially the jackdaws in the subgenus Coloeus
Coloeus
Coloeus is a subgenus of the bird genus Corvus, the crows and allies. It contains two relatively small species both named as jackdaws. They have a blackish crown, wings and tail, the rest of the plumage being paler....
, but DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...
and cytochrome b analysis shows that the genus Pyrrhocorax, along with the Ratchet-tailed Treepie
Ratchet-tailed Treepie
The Ratchet-tailed Treepie is a species of bird in the Corvidae family. It is monotypic within the genus Temnurus.It is found in Cambodia, China, Laos, Thailand, and Vietnam....
(genus Temnurus), diverged early from the rest of the Corvidae
Corvidae
Corvidae is a cosmopolitan family of oscine passerine birds that contains the crows, ravens, rooks, jackdaws, jays, magpies, treepies, choughs and nutcrackers. The common English names used are corvids or the crow family , and there are over 120 species...
.
The genus name is derived from Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
πύρρος (purrhos), "flame-coloured", and κόραξ (korax), "raven". The species epithet graculus is Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
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
Jackdaw
The Jackdaw , sometimes known as the Eurasian Jackdaw, European Jackdaw or Western Jackdaw, is a passerine bird in the crow family. Found across Europe, western Asia and North Africa, it is mostly sedentary, although northern and eastern populations migrate south in winter. Four subspecies are...
, Corvus monedula, based on its call. The Red-billed Chough, formerly particularly common in Cornwall
Cornwall
Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
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 Caucusus and northern Iran.
- P. g. digitatus, described by the German naturalists Wilhelm HemprichWilhelm HemprichWilhelm Friedrich Hemprich was a German naturalist and explorer.Hemprich was born in Glatz , Prussian Silesia, and studied medicine at Breslau and Berlin...
and Christian Gottfried EhrenbergChristian Gottfried EhrenbergChristian Gottfried Ehrenberg , German naturalist, zoologist, comparative anatomist, geologist, and microscopist, was one of the most famous and productive scientists of his time.- Early collections :...
as P. alpinus var. digitatus in 1833, is larger and has stronger feet than the nominate race. It breeds in the rest of the depicted Asian range, mainly in the Himalayas.
Moravia
Moravia
Moravia is a historical region in Central Europe in the east of the Czech Republic, and one of the former Czech lands, together with Bohemia and Silesia. It takes its name from the Morava River which rises in the northwest of the region...
n palaeontologist
Paleontology
Paleontology "old, ancient", ὄν, ὀντ- "being, creature", and λόγος "speech, thought") is the study of prehistoric life. It includes the study of fossils to determine organisms' evolution and interactions with each other and their environments...
Ferdinand Stoliczka
Ferdinand Stoliczka
Ferdinand Stoliczka was a Moravian palaeontologist who worked in India on paleontology, geology and various aspects of zoology. He died of high altitude sickness during an expedition across the Himalayas.-Early life:Stoliczka was born at the lodge Zámeček near Kroměříž in Moravia...
separated the Himalayan population as a third subspecies, P. g. forsythi, but this has not been widely accepted and is usually treated as synonym
Synonym
Synonyms are different words with almost identical or similar meanings. Words that are synonyms are said to be synonymous, and the state of being a synonym is called synonymy. The word comes from Ancient Greek syn and onoma . The words car and automobile are synonyms...
ous with digitatus. A Pleistocene
Pleistocene
The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
form from Europe was similar to the extant subspecies, and is sometimes categorised as P. g. vetus.
The Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
n White-winged Chough
White-winged Chough
The White-winged Chough is one of only two surviving members of the Australian mud-nest builders family, Corcoracidae, and is the only member of the genus Corcorax...
, Corcorax melanorhamphos, despite its similar bill shape and black plumage, is only distantly related to the true choughs.
Description
Plumage
Plumage refers both to the layer of feathers that cover a bird and the pattern, colour, and arrangement of those feathers. The pattern and colours of plumage vary between species and subspecies and can also vary between different age classes, sexes, and season. Within species there can also be a...
, a short yellow bill, dark brown irises
Iris (anatomy)
The iris is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupils and thus the amount of light reaching the retina. "Eye color" is the color of the iris, which can be green, blue, or brown. In some cases it can be hazel , grey, violet, or even pink...
, and red legs. It is slightly smaller than Red-billed Chough, at 37–39 centimetres (14.6–15.3 in) length with a 12–14 cm (4.7–5.5 in) tail and a 75–85 cm (29.5–33.5 in) wingspan, but has a proportionally longer tail and shorter wings than its relative. It has a similar buoyant and easy flight. 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 Alpine Chough is unlikely to be confused with any other species; although the Jackdaw and Red-billed Chough share its range, the Jackdaw is smaller and has unglossed grey plumage, and the Red-billed Chough has a long red bill.
The subspecies P. g. digitatus averages slightly larger than the nominate form, weighing 191–244 grams (6.8–8.7 oz) against 188–252 g (6.7–9.0 oz) for P. g. graculus, and it has stronger feet. This is in accordance with Bergmann's rule
Bergmann's Rule
Bergmann's rule is an ecogeographic principle that states that within a broadly distributed genus, species of larger size are found in colder environments, and species of smaller size are found in warmer regions. Although originally formulated in terms of species within a genus, it has often been...
, which predicts that the largest birds should be found higher elevations or in colder and more arid regions. The extremities of the body, the bill and tarsus
Tarsus (skeleton)
In tetrapods, the tarsus is a cluster of articulating bones in each foot situated between the lower end of tibia and fibula of the lower leg and the metatarsus. In the foot the tarsus articulates with the bones of the metatarsus, which in turn articulate with the bones of the individual toes...
, were longer in warmer areas, in line with Allen's rule
Allen's rule
Allen's rule is a biological rule posited by Joel Asaph Allen in 1877. It states that endotherms from colder climates usually have shorter limbs than the equivalent animals from warmer climates.- Theory :...
. Temperature seemed to be the most important cause of body variation in the Alpine Chough.
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
Vertical draft
An updraft or downdraft is the vertical movement of air as a weather related phenomenon. One of two forces causes the air to move. Localized regions of warm or cool air will exhibit vertical movement. A mass of warm air will typically be less dense than the surrounding region, and so will rise...
at cliff faces. Even in flight, it can be distinguished from Red-billed Chough by its less rectangular wings, and longer, less square-ended tail.
The rippling
Trill (music)
The trill is a musical ornament consisting of a rapid alternation between two adjacent notes, usually a semitone or tone apart, which can be identified with the context of the trill....
preep and whistled sweeeooo calls of the Alpine Chough are quite different from the more typically crow-like
Crow
Crows form the genus Corvus in the family Corvidae. Ranging in size from the relatively small pigeon-size jackdaws to the Common Raven of the Holarctic region and Thick-billed Raven of the highlands of Ethiopia, the 40 or so members of this genus occur on all temperate continents and several...
chee-ow vocalisations of the Jackdaw and the Red-billed Chough. It also has a rolling churr alarm call, and a variety of quiet warbles and squeaks given by resting or feeding birds. In a study of chough calls throughout the Palearctic region it was found that call frequencies
Audio frequency
An audio frequency or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human...
in the Alpine Chough showed an inverse relationship
Inverse relationship
An inverse or negative relationship is a mathematical relationship in which one variable, say y, decreases as another, say x, increases. For a linear relation, this can be expressed as y = a-bx, where -b is a constant value less than zero and a is a constant...
between body size and frequency, being higher-pitched in smaller-bodied populations.
Distribution and habitat
Alps
The Alps is one of the great mountain range systems of Europe, stretching from Austria and Slovenia in the east through Italy, Switzerland, Liechtenstein and Germany to France in the west....
across Central Asia
Central Asia
Central Asia is a core region of the Asian continent from the Caspian Sea in the west, China in the east, Afghanistan in the south, and Russia in the north...
and the Himalayas
Himalayas
The Himalaya Range or Himalaya Mountains Sanskrit: Devanagari: हिमालय, literally "abode of snow"), usually called the Himalayas or Himalaya for short, is a mountain range in Asia, separating the Indian subcontinent from the Tibetan Plateau...
to western China. There are also populations in Morocco
Morocco
Morocco , officially the Kingdom of Morocco , is a country located in North Africa. It has a population of more than 32 million and an area of 710,850 km², and also primarily administers the disputed region of the Western Sahara...
, Corsica
Corsica
Corsica is an island in the Mediterranean Sea. It is located west of Italy, southeast of the French mainland, and north of the island of Sardinia....
and Crete
Crete
Crete is the largest and most populous of the Greek islands, the fifth largest island in the Mediterranean Sea, and one of the thirteen administrative regions of Greece. It forms a significant part of the economy and cultural heritage of Greece while retaining its own local cultural traits...
. It is a non-migratory resident
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...
throughout its range, although Moroccan birds have established a small colony near Málaga
Málaga
Málaga is a city and a municipality in the Autonomous Community of Andalusia, Spain. With a population of 568,507 in 2010, it is the second most populous city of Andalusia and the sixth largest in Spain. This is the southernmost large city in Europe...
in southern Spain, and wanderers have reached Czechoslovakia
Czechoslovakia
Czechoslovakia or Czecho-Slovakia was a sovereign state in Central Europe which existed from October 1918, when it declared its independence from the Austro-Hungarian Empire, until 1992...
, Gibraltar
Gibraltar
Gibraltar is a British overseas territory located on the southern end of the Iberian Peninsula at the entrance of the Mediterranean. A peninsula with an area of , it has a northern border with Andalusia, Spain. The Rock of Gibraltar is the major landmark of the region...
, Hungary
Hungary
Hungary , officially the Republic of Hungary , is a landlocked country in Central Europe. It is situated in the Carpathian Basin and is bordered by Slovakia to the north, Ukraine and Romania to the east, Serbia and Croatia to the south, Slovenia to the southwest and Austria to the west. The...
and Cyprus
Cyprus
Cyprus , officially the Republic of Cyprus , is a Eurasian island country, member of the European Union, in the Eastern Mediterranean, east of Greece, south of Turkey, west of Syria and north of Egypt. It is the third largest island in the Mediterranean Sea.The earliest known human activity on the...
.
This is a high-altitude species normally breeding between 1260–2880 m (4,133.9–9,448.8 ft) in Europe, 2880–3900 m (9,448.8–12,795.3 ft) in Morocco, and 3500–5000 m (11,482.9–16,404.2 ft) in the Himalayas. It has nested at 6500 m (21,325.5 ft), higher than any other bird species, even surpassing the Red-billed Chough which has a diet less well adapted to the highest altitudes. It has been observed following mountaineers ascending Mount Everest
Mount Everest
Mount Everest is the world's highest mountain, with a peak at above sea level. It is located in the Mahalangur section of the Himalayas. The international boundary runs across the precise summit point...
at an altitude of 8200 m (26,902.9 ft). 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 slope
Scree
Scree, also called talus, is a term given to an accumulation of broken rock fragments at the base of crags, mountain cliffs, or valley shoulders. Landforms associated with these materials are sometimes called scree slopes or talus piles...
s to the tree line or lower, and in winter will often congregate around human settlements, ski resort
Ski resort
A ski resort is a resort developed for skiing and other winter sports. In Europe a ski resort is a town or village in a ski area - a mountainous area, where there are ski trails and supporting services such as hotels and other accommodation, restaurants, equipment rental and a ski lift system...
s, hotels and other tourist facilities. Its penchant for waiting by hotel windows for food is popular with tourists, but less so with hotel owners.
Breeding
Monogamy
Monogamy /Gr. μονός+γάμος - one+marriage/ a form of marriage in which an individual has only one spouse at any one time. In current usage monogamy often refers to having one sexual partner irrespective of marriage or reproduction...
, showing high partner fidelity in summer and winter and from year to year. Nesting typically starts in early May, and is non-colonial, although in suitable habitat several pairs may nest in close proximity. The bulky nests are composed of roots, sticks and plant stems lined with grass, fine twiglets or hair, and may be constructed on ledges, in a cave or similar fissure in a cliff face, or in an abandoned building. The clutch
Clutch (eggs)
A clutch of eggs refers to all the eggs produced by birds or reptiles, often at a single time, particularly those laid in a nest.In birds, destruction of a clutch by predators, , results in double-clutching...
is 3–5 glossy whitish eggs, averaging 33.9 by 24.9 mm (1.3 by 0.980314960629921 in) in size, which are tinged with buff, cream or light-green and marked with small brown blotches; they are incubated by the female for 14–21 days before hatching. The chicks hatch with a dense covering of natal down
Down feather
The down of birds is a layer of fine feathers found under the tougher exterior feathers. Very young birds are clad only in down. Powder down is a specialized type of down found only in a few groups of birds. Down is a fine thermal insulator and padding, used in goods such as jackets, bedding,...
, in contrast to those of the Red-billed Chough which are almost naked, and fledge
Fledge
Fledge is the stage in a young bird's life when the feathers and wing muscles are sufficiently developed for flight. It also describes the act of a chick's parents raising it to a fully grown state...
in a further 29–31 days from hatching. The young birds are fed by both parents, and may also be fed by other adults when they have fledged and joined the flock. Breeding is possible in the high mountains because chough eggs have relatively fewer pores than those of lowland species, and lose less water by evaporation at low atmospheric pressure. The embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s 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.
A study of three different European populations showed a mean clutch size of 3.6 eggs, producing 2.6 chicks, of which 1.9 fledged. Adult survival rate varied from 83 to 92%, with no significant difference detected between males and females. Survival of first-year birds was, at 77%, lower than that of adults. The availability or otherwise of human food supplied from tourist activities did not affect breeding success.
Feeding
In the summer, the Alpine Chough feeds mainly on invertebrateInvertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s collected from pasture, such as beetle
Beetle
Coleoptera is an order of insects commonly called beetles. The word "coleoptera" is from the Greek , koleos, "sheath"; and , pteron, "wing", thus "sheathed wing". Coleoptera contains more species than any other order, constituting almost 25% of all known life-forms...
s (Selatosomus aeneus
Selatosomus aeneus
Selatosomus aeneus is a species of click beetle found in Europe. It was originally described as Corymbites aeneus by Linnaeus....
and Otiorhynchus morio
Otiorhynchus morio
Otiorhynchus morio is one of the many species in the weevil family . It was first described by German entomologist Ernst Friedrich Germar in 1824.-External links:*...
have been recorded from pellets
Pellet (ornithology)
A pellet, in ornithology, is the mass of undigested parts of a bird's food that some bird species occasionally regurgitate. The contents of a bird's pellet depend on its diet, but can include the exoskeletons of insects, indigestible plant matter, bones, fur, feathers, bills, claws, and teeth...
), snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...
s, grasshopper
Grasshopper
The grasshopper is an insect of the suborder Caelifera in the order Orthoptera. To distinguish it from bush crickets or katydids, it is sometimes referred to as the short-horned grasshopper...
s, caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
s and fly
Fly
True flies are insects of the order Diptera . They possess a pair of wings on the mesothorax and a pair of halteres, derived from the hind wings, on the metathorax...
larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e. The diet in autumn, winter and early spring becomes mainly fruit, including berries
Berry
The botanical definition of a berry is a fleshy fruit produced from a single ovary. Grapes are an example. The berry is the most common type of fleshy fruit in which the entire ovary wall ripens into an edible pericarp. They may have one or more carpels with a thin covering and fleshy interiors....
such as the European Hackberry (Celtis australis
Celtis australis
Celtis australis, commonly known as the European nettle tree, Mediterranean hackberry, lote tree, or honeyberry, is a deciduous tree that can grow 20 or 25 meters in height....
) and Sea-buckthorn (Hippophae rhamnoides
Sea-buckthorn
The sea-buckthorns are deciduous shrubs in the genus Hippophae, family Elaeagnaceae. The name sea-buckthorn is hyphenated here to avoid confusion with the buckthorns...
), rose hip
Rose hip
The rose hip, or rose haw, is the fruit of the rose plant, that typically is red-to-orange, but ranges from dark purple to black in some species. Rose hips begin to form in spring, and ripen in late summer through autumn.-Usage:...
s, and domesticated crops such as apples, grapes and pears where available. It has been observed eating flowers of Crocus vernus albiflorus
Crocus vernus
Crocus vernus is a species in Family Iridaceae. Its cultivars and those of Crocus flavus are used as ornamental plants. The Dutch Crocusses are larger than the other cultivated crocus species...
, including the pistils
Gynoecium
Gynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...
, perhaps as a source of carotenoid
Carotenoid
Carotenoids are tetraterpenoid organic pigments that are naturally occurring in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms like algae, some bacteria, and some types of fungus. Carotenoids can be synthesized fats and other basic organic metabolic building...
s. The chough will readily supplement its winter diet with food provided by tourist activities in mountain regions, including ski resorts, refuse dump
Landfill
A landfill site , is a site for the disposal of waste materials by burial and is the oldest form of waste treatment...
s and picnic areas
Picnic
In contemporary usage, a picnic can be defined simply as a pleasure excursion at which a meal is eaten outdoors , ideally taking place in a beautiful landscape such as a park, beside a lake or with an interesting view and possibly at a public event such as before an open air theatre performance,...
. 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. Foraging areas change altitudinally through the year, depending on climatic factors, food availability and food quality. During the breeding season, birds remain above the tree line, although they may use food provided by tourists at refuges and picnic areas.
Movement to lower levels begins after the first snowfalls, and feeding by day is mainly in or near valley bottoms when the snow cover deepens, although the birds return to the mountains to roost. In March and April the choughs frequent villages at valley tops or forage in snow-free patches prior to their return to the high meadows. Feeding trips may cover 20 km (12.4 mi) distance and 1600 m (5,249.3 ft) in altitude. In the Alps, the development of skiing above 3000 m (9,842.5 ft) has enabled more birds to remain at high levels in winter.
Where their ranges overlap, the two chough species may feed together in the summer, although 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 exclusively Gagea
Gagea
Gagea is a large genus of spring flowers in the Liliaceae found in Europe and western Asia. It is named after the English naturalist Sir Thomas Gage...
bulbs dug from the ground, whilst the Alpine Chough took berries and hips. In June, Red-billed Choughs fed mainly on caterpillars whereas Alpine Choughs ate crane fly
Crane fly
A crane fly is an insect in the family Tipulidae. Adults are very slender, long-legged flies that may vary in length from though tropical species may exceed to ....
pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
e. Later in the summer, the Alpine Chough consumed large numbers of grasshoppers, while the Red-billed Chough added cranefly pupae, fly larvae and beetles to its diet. In the eastern Himalayas in November, Alpine Choughs occur mainly in juniper
Juniper
Junipers are coniferous plants in the genus Juniperus of the cypress family Cupressaceae. Depending on taxonomic viewpoint, there are between 50-67 species of juniper, widely distributed throughout the northern hemisphere, from the Arctic, south to tropical Africa in the Old World, and to the...
forests where they feed on juniper berries
Juniper berry
A juniper berry is the female seed cone produced by the various species of junipers. It is not a true berry but a cone with unusually fleshy and merged scales, which give it a berry-like appearance. The cones from a handful of species, especially Juniperus communis, are used as a spice,...
, 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.
Natural threats
Predators of the choughs include the Peregrine FalconPeregrine Falcon
The Peregrine Falcon , also known as the Peregrine, and historically as the Duck Hawk in North America, is a widespread bird of prey in the family Falconidae. A large, crow-sized falcon, it has a blue-gray back, barred white underparts, and a black head and "moustache"...
, Golden Eagle
Golden Eagle
The Golden Eagle is one of the best known birds of prey in the Northern Hemisphere. Like all eagles, it belongs to the family Accipitridae. Once widespread across the Holarctic, it has disappeared from many of the more heavily populated areas...
and Eurasian Eagle-owl, while the Common Raven
Common Raven
The Common Raven , also known as the Northern Raven, is a large, all-black passerine bird. Found across the northern hemisphere, it is the most widely distributed of all corvids...
will take nestlings.
Alpine Choughs have been observed diving at a Tibetan red fox
Red Fox
The red fox is the largest of the true foxes, as well as being the most geographically spread member of the Carnivora, being distributed across the entire northern hemisphere from the Arctic Circle to North Africa, Central America, and the steppes of Asia...
. It seems likely that this “mobbing
Mobbing
Mobbing in the context of human beings either means bullying of an individual by a group in any context. Identified as emotional abuse in the workplace, such as "ganging up" by co-workers, subordinates or superiors, to force someone out of the workplace through rumor, innuendo, intimidation,...
” 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
Flea
Flea is the common name for insects of the order Siphonaptera which are wingless insects with mouthparts adapted for piercing skin and sucking blood...
Ceratophyllus vagabunda, two specialist chough fleas Frontopsylla frontalis and F. laetus, a cestode
Cestoda
This article describes the flatworm. For the medical condition, see Tapeworm infection.Cestoda is the name given to a class of parasitic flatworms, commonly called tapeworms, of the phylum Platyhelminthes. Its members live in the digestive tract of vertebrates as adults, and often in the bodies...
Choanotaenia pirinica, and various species of chewing lice
Chewing louse
Mallophaga is a suborder of lice, known as chewing lice, biting lice or bird lice, containing more than 3000 species. They have paurometabolis or incomplete metamorphosis....
in the genera Brueelia
Brueelia
Brueelia is a genus of lice in the family Philopteridae, containing the following species:* Brueelia amandavae Rekasi & Saxena, 2005* Brueelia astrildae Tendeiro & Mendes, 1994* Bureelia cantans Sychra, 2010...
, Menacanthus
Menacanthus
Menacanthus is a genus of chewing lice which parasitise birds. The taxonomy of this genus is highly uncertain. Most taxonomies have given this genus as having over a hundred species, but recent studies have synonymised dozens of species and found other names to be invalid. Some Menacanthus species...
and Philopterus.
Status
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 ConcernLeast Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
.
At the greatest extent of the last glacial period around 18,000 years ago, southern Europe was characterised by cold open habitats, and the Alpine Chough was found as far as south as southern Italy, well outside its current range. Some of these peripheral prehistoric populations persisted until recently, only to disappear within the last couple of centuries. In the Polish
Poland
Poland , officially the Republic of Poland , is a country in Central Europe bordered by Germany to the west; the Czech Republic and Slovakia to the south; Ukraine, Belarus and Lithuania to the east; and the Baltic Sea and Kaliningrad Oblast, a Russian exclave, to the north...
Tatra Mountains
Tatra Mountains
The Tatra Mountains, Tatras or Tatra , are a mountain range which forms a natural border between Slovakia and Poland, and are the highest mountain range in the Carpathian 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
Intensive farming
Intensive farming or intensive agriculture is an agricultural production system characterized by the high inputs of capital, labour, or heavy usage of technologies such as pesticides and chemical fertilizers relative to land area....
methods have been introduced, such as Brittany
Brittany
Brittany is a cultural and administrative region in the north-west of France. Previously a kingdom and then a duchy, Brittany was united to the Kingdom of France in 1532 as a province. Brittany has also been referred to as Less, Lesser or Little Britain...
, England, south-west Portugal and mainland Scotland.
Choughs can be locally threatened by the accumulation of pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
s and heavy metals in the mountain soils, heavy rain, shooting and other human disturbances, but a longer-term threat comes from global warming
Global warming
Global warming refers to the rising average temperature of Earth's atmosphere and oceans and its projected continuation. In the last 100 years, Earth's average surface temperature increased by about with about two thirds of the increase occurring over just the last three decades...
, which would cause the species' preferred Alpine climate
Alpine climate
Alpine climate is the average weather for a region above the tree line. This climate is also referred to as mountain climate or highland climate....
zone to shift to higher, more restricted areas, or locally to disappear entirely. Fossils of both chough species were found in the mountains of the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
. 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.
External links
- Alpine Chough videos, photos & sounds on the Internet Bird Collection