It 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 merely geographical races of one species. The fact that hybridization was observed where their ranges overlapped 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 Hooded Crow species itself, four subspecies are recognized, with one, the Mesopotamian Crow, possibly distinct enough to warrant species status itself.
It is locally known as a Hoodie in Northern Ireland.
Except for the head, throat, wings, tail and thigh feathers, which are black and mostly glossy, the plumage is ash-grey, the dark shafts giving it a streaky appearance. The bill and legs are black; the iris dark brown. There is only one moult in autumn, as in other crow species. The male is the larger bird, otherwise the sexes are alike. The flight is slow and heavy and usually straight. The length varies from 48 to 52 cm (19-20 in). When first hatched the young are much blacker than the parents. Juveniles have duller plumage with bluish or greyish eyes and initially a red mouth. Wingspan is 98 cm (39 in) and weight is on average 510 grammes.
The Hooded Crow, with its contrasted greys and blacks, cannot be confused with either the Carrion Crow or Rook, but the call notes of the two are almost indistinguishable.
The Hooded Crow breeds in northern and eastern Europe, and closely allied forms inhabit southern Europe and western Asia. Where its range overlaps with Carrion Crow, as in northern Britain, Germany, Denmark, northern Italy and Siberia, their hybrids are fertile. However, the hybrids are less well-adapted than pure-bred birds, and this is one of the reasons that this species was split from the Carrion Crow. There are some areas, such as Iran and central Russia, where little or no interbreeding occurs.
In the British Isles, the Hooded Crow breeds regularly in Scotland, the Isle of Man, and in 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, and in Hertfordshire was known as the Royston Crow after the town of Royston. The 150-year old local newspaper is still titled Royston Crow, and depicts the bird’s head on its masthead.
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, and 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 it will enter the burrow of the Puffin to steal eggs.
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 British Isles, 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 4.3 x 3.0 centimetres (1.7 x 1.2 in) in size and weigh 19.8 grammes (0.71 oz), of which 6% is shell. The altricial young are incubated for 17-19 days by the female alone, who is fed by the male. They fledge after 32-36 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 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.