Corvus Cornix

The hooded crow (''Corvus cornix''), also colloquially called just hoodie, is a Eurasian bird species in the genus ''Corvus''. Widely distributed, it is found across Northern, Eastern, and Southeastern Europe, as well as parts of the Middle East. It is an ashy grey bird with black head, throat, wings, tail, and thigh feathers, as well as a black bill, eyes, and feet. Like other corvids, it is an omnivorous and opportunistic forager and feeder.

The hooded crow is so similar in morphology and habits to the carrion crow (''Corvus corone'') that for many years they were considered by most authorities to be geographical subcategories of one species. Extensive but geographically restricted hybridisation observed where their ranges met added weight to this view. However, since 2002, the hooded crow has been elevated to full species status after closer observation; the hybridisation was less than expected and hybrids had decreased vigour. Within the species, four subspecies are accepted.

Taxonomy

The hooded crow was one of the many species originally described by Carl Linnaeus in his landmark 1758 10th edition of ''Systema Naturae''; he gave it the binomial name ''Corvus cornix''. Linnaeus specified the type locality as "Europa", but this was restricted to Sweden by the German ornithologist Ernst Hartert in 1903. The genus name ''Corvus'' is Latin for "raven" while the specific epithet ''cornix'' is Latin for "crow". The hooded crow was subsequently considered a subspecies of the carrion crow for many years, hence known as ''Corvus corone cornix'', due to similarities in structure and habits.

Etymology

The name hooded crow, first known from Scotland in the early 16th century, was established as the standard name by use in Robert Sibbald's ''Scotia Illustrata'' in 1684 and Thomas Pennant's ''British Zoology'' in 1776, and was formally adopted by the International Ornithologists' Union (IOC) when it was split as a separate species from the carrion crow. It is locally known as a 'hoodie craw' or simply 'hoodie' in Scotland and as a grey crow in Northern Ireland. Its status as a scarce winter visitor from Scandinavia in eastern England has led to a number of historical local names, including "Coatham crow" (from Coatham in North Yorkshire), "Royston crow" (from Royston in Hertfordshire), "Scremerston crow" (from Scremerston in Northumberland), "Danish crow" and "winter crow". In Irish, it is called and in Welsh , or the "grey crow", as its name also means in Danish, Swedish, Italian, Spanish, and several Slavic languages. It is referred to as the "pied crow" (') in Dutch and "fog crow" (') in German, and the "dolman crow" (') in Hungarian.

Subspecies

Four subspecies of hooded crow are now accepted; previously, all were considered subspecies of ''Corvus corone''. A fifth subspecies, ''C. c. sardonius'' ( Kleinschmidt, 1903) has been listed, although it has been alternately partitioned between ''C. c. sharpii'' (most populations), ''C. c. cornix'' (Corsican population), and the Middle Eastern ''C. c. pallescens''.

* ''C. c. cornix'' Linnaeus, 1758 – the nominate subspecies, occurs in Britain, Ireland and the rest of Europe south to Corsica.
* ''C. c. sharpii'' Oates, 1889 – named after the English zoologist Richard Bowdler Sharpe. This is a paler grey form found from western Siberia through to the Caucasus region and Iran.
* ''C. c. pallescens'' ( Madarász, 1904) – the smallest subspecies, found in Turkey and Egypt, and is a paler form as its name suggests.
* ''C. c. capellanus'' Sclater, PL, 1877 – sometimes considered a separate species. This distinctive form occurs in Iraq and southwestern Iran. It has very pale grey plumage, which looks almost white from a distance. It is possibly distinct enough to be considered a separate species.Madge, Steve & Burn, Hilary (1994): ''Crows and jays: a guide to the crows, jays and magpies of the world''. A&C Black, London.

Genetic difference from carrion crows

The hooded crow (''Corvus cornix'') and carrion crow (''Corvus corone'') are two closely related species whose geographical distribution across Europe is illustrated in the accompanying diagram. It is believed that this distribution might have resulted from the glaciation cycles during the Pleistocene, which caused the parent population to split into isolates which subsequently re-expanded their ranges when the climate warmed causing secondary contact. Jelmer Poelstra and coworkers sequenced almost the entire genomes of both species in populations at varying distances from the contact zone to find that the two species were nearly genetically identical, both in their DNA and in its expression (in the form of ''m''RNA), except for the ''lack of expression'' of a small portion (<0.28%) of the genome (situated on avian chromosome 18) in the hooded crow, which imparts the lighter plumage colouration on its torso. Thus the two species can hybridise viably, and regularly do so at the contact zone, but the all-black carrion crows on the one side of the contact zone mate almost exclusively with other all-black carrion crows, while the same occurs among the hooded crows on the other side of the contact zone. This is an example of assortative mating. They concluded that it was only the outward appearance of the two species that inhibits hybridisation.

Description

Except for the head, throat, wings, tail, and thigh feathers, which are black and mostly glossy, the plumage of the hooded crow is ash-grey, with the dark shafts giving it a streaky appearance. The bill and legs are black; the iris dark brown. Only one moult occurs, in autumn, as in other crow species. Male hooded crows tend to be larger than females, although the two sexes are otherwise similar in appearance. Their flight is slow, heavy and usually straight. Their length varies from . When first hatched, the young are much blacker than the parents. Juveniles have duller plumage with bluish or greyish eyes, and initially possess a red mouth. The wingspan is and weight is on average 510 g.

The hooded crow, with its contrasted greys and blacks, is visually distinct from both the carrion crow and the rook, but the call notes of the hooded and carrion crows are almost indistinguishable.

Distribution

The hooded crow breeds in northern and eastern Europe, and closely allied forms inhabit southern Europe and western Asia. Fertile hybrids are produced where its range meets with that of the carrion crow, as in northern Britain, Germany, Denmark, northern Italy, and Siberia. However, the hybrids are less well-adapted than purebred birds and the hybrid zone remains consistently narrow; this was one of the main reasons behind its reclassification as a distinct species from the carrion crow.

In the British Isles, the hooded crow breeds regularly in northern and western Scotland, the Isle of Man, and the Scottish Islands; it also breeds throughout Ireland. In autumn, some migratory birds arrive on the east coast of Britain. In the past, this was a more common visitor.

Behaviour

Diet

The hooded crow is omnivorous, with a diet similar to that of the carrion crow, and is a constant scavenger. It drops molluscs and crabs to break them after the manner of the carrion crow, to the point that an old Scottish name for empty sea urchin shells was "crow's cups". On coastal cliffs, the eggs of gulls, cormorants, and other birds are stolen when their owners are absent, and hooded crows will enter the burrows of puffins to steal eggs. It will also feed on small mammals, scraps, smaller birds, and carrion. The hooded crow often hides food to feed on later, especially meat, nuts, and any insects that may be present on these, in places such as rain gutters, flower pots, or in the earth under bushes. Other crows will often watch a crow that hides food and then search the hiding place later when the first crow has left.

Nesting

Nesting occurs later in colder regions; mid-May to mid-June in northwest Russia, Shetland, and the Faroe Islands, and late February in the Persian Gulf region. In warmer parts of Europe, the clutch is laid in April. The bulky stick nest is normally placed in a tall tree, but cliff ledges, old buildings, and pylons may be used. Nests are occasionally placed on or near the ground. The nest resembles that of the carrion crow, but on the coast, seaweed is often interwoven in the structure, and animal bones and wire are also frequently incorporated. The four to six brown-speckled blue eggs are in size and weigh , of which 6% is shell. The altricial young are incubated for 17–19 days by the female alone, that is fed by the male. They fledge after 32 to 36 days. Incubating females have been reported to obtain most of their own food and later that for their young.

The typical lifespan is unknown, but that of the carrion crow is four years. The maximum recorded age for a hooded crow is 16 years, and 9 months.

This species is a secondary host of the parasitic great spotted cuckoo, the European magpie being the preferred host. However, in areas where the latter species is absent, such as Israel and Egypt, the hooded crow becomes the normal corvid host.Snow & Perrins (1998) 873–4

This species, like its relative, is regularly killed by farmers and on grouse estates. In County Cork, Ireland, the county's gun clubs shot over 23,000 hooded crows in two years in the early 1980s. Since 1981, they have been protected under the Wildlife and Countryside Act, meaning it is illegal to knowingly kill, injure, or capture them.

File:Corvus corone cornix MHNT.ZOO.2010.11.175.4.jpg, Eggs of ''Corvus corone cornix '' - MHNT
File:Crow Nest Moscow.jpg, Nest with eggs in urban environment, Moscow
File:Crow babies 10 days old.jpg, Ten-day-old chicks
File:Kråka - Corvus cornix.jpg, Juvenile hooded crows in Sweden

Status

The IUCN Red List does not distinguish the hooded crow from the carrion crow, but the two species together have an extensive range, estimated at , and a large population, including an estimated 14 to 34 million individuals in Europe alone. They are not believed to approach the thresholds for the population decline criterion of the IUCN Red List (i.e., declining more than 30% in ten years or three generations), so are evaluated as least concern. The carrion crow and hooded crow hybrid zone is slowly spreading northwest, but the hooded crow has on the order of three million territories in just Europe (excluding Russia). This movement is also attested to by the fact that in April 2020 the hooded crow was redlisted in Sweden, where the Species Information Centre does distinguish between hooded and carrion crow.

Cultural significance

In Irish folklore, the bird appears on the shoulder of the dying Cú Chulainn, and could also be a manifestation of the Morrígan, the wife of Tethra, or the Cailleach. This idea has persisted, and the hooded crow is associated with fairies in the Scottish highlands and Ireland; in the 18th century, Scottish shepherds would make offerings to them to keep them from attacking sheep. In Faroese folklore, a maiden would go out on Candlemas morn and throw a stone, then a bone, then a clump of turf at a hooded crow – if it flew over the sea, her husband would be a foreigner; if it landed on a farm or house, she would marry a man from there, but if it stayed put, she would remain unmarried.

The old name of Royston crow originates from the days when this bird was a common winter visitor to southern England, with the sheep fields around Royston, Hertfordshire providing carcasses on which the birds could feed. The local newspaper, founded in 1855, is called '' The Royston Crow'', and the hooded crow also features on the town's coat of arms.

The hooded crow is one of the 37 Norwegian birds depicted in the Bird Room of the Royal Palace in Oslo.

References

External links

Cyberbirding: hooded crow pictures

Profile shot of bird

Skull of hooded crow (without beak sheath)


Video of wild hooded crow in Warsaw trying to imitate human speech

Educational article with video about Hooded Crow

{{Taxonbar , from=Q25405

Corvus
Crows
Birds of Europe
Birds of West Asia
Birds described in 1758
Taxa named by Carl Linnaeus
Articles containing video clips
Taxobox binomials not recognized by IUCN