Cornacchia grigia

Identificazione

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.[citation needed] Their length varies from 48 to 52 cm (19 to 20 in). 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. Wingspan is 105 cm (41 in) and weight is on average 510 g.<p>The hooded crow, with its contrasted greys and blacks, is visually distinct from both the carrion crow and the rook, but the kraaⓘ call notes of the hooded and carrion crows are almost indistinguishable.[9]

Tassonomia

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. "Hooded crow" has been designated as the official name by the International Ornithologists' Union (IOC). It is locally known as a 'hoodie craw' or simply 'hoodie' in Scotland and as a grey crow in Northern Ireland. It is also known locally as "Scotch crow" and "Danish crow". In Irish, it is called caróg liath, or the "grey crow", as its name also means in the Slavic languages and in Danish. It is referred to as the "mist crow" (Nebelkrähe) in German, and the "dolman crow" (dolmányos varjú) in Hungarian.[citation needed]<p>Four subspecies of the hooded crow are now recognised; 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.[citation needed]

Nome scientifico

Corvus cornix

Autorità

Linnaeus, 1758

Ordine

Passeriformi

Famiglia

Corvidi

Genere

Corvus

Areale e habitat

The hooded crow breeds in northern and eastern Europe, and closely allied forms inhabit southern Europe and western Asia. Where its range overlaps with that of the carrion crow, as in northern Britain, Germany, Denmark, northern Italy, and Siberia, their hybrids are fertile. However, the hybrids are less well-adapted than purebred birds (one of the reasons behind its reclassification as a distinct species from the carrion crow). <p>In the British Isles, the hooded crow breeds regularly in Scotland, the Isle of Man, and the Scottish Islands; it also breeds widely in Ireland. In autumn, some migratory birds arrive on the east coast of Britain. In the past, this was a more common visitor.

Comportamento

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.[citation needed]<p>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 the European Archipelago, 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 .mw-parser-output .frac{white-space:nowrap}.mw-parser-output .frac .num,.mw-parser-output .frac .den{font-size:80%;line-height:0;vertical-align:super}.mw-parser-output .frac .den{vertical-align:sub}.mw-parser-output .sr-only{border:0;clip:rect(0,0,0,0);clip-path:polygon(0px 0px,0px 0px,0px 0px);height:1px;margin:-1px;overflow:hidden;padding:0;position:absolute;width:1px}4.3 cm × 3.0 cm (1+3⁄4 in × 1+1⁄8 in) in size and weigh 19.8 g (11⁄16 oz), 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.<p>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.<p>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.<p>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.