Carrion crow (Corvus corone)

The carrion crow (Corvus corone) is a passerine bird of the family Corvidae and the genus Corvus which is native to western Europe and eastern Asia.

Description
The plumage of carrion crow is black with a green or purple sheen, much greener than the gloss of the rook. The bill, legs and feet are also black. It can be distinguished from the common raven by its size (48–52 cm or 19 to 20 inches in length as compared to an average of 63 centimetres (25 inches) for ravens) and from the hooded crow by its black plumage. The carrion crow has a wingspan of 84–100 cm or 33 to 39 inches and weighs 400-600 grams.

There is frequent confusion between the carrion crow and the rook, another black corvid found within its range. The beak of the crow is stouter and in consequence looks shorter, and whereas in the adult rook the nostrils are bare, those of the crow are covered at all ages with bristle-like feathers. As well as this, the wings of a carrion crow are proportionally shorter and broader than those of the rook when seen in flight.

Behaviour and ecology
The rook is generally gregarious and the crow solitary, but rooks occasionally nest in isolated trees, and crows may feed with rooks; moreover, crows are often sociable in winter roosts. The most distinctive feature is the voice. The rook has a high-pitched kaaa, but the crow's guttural, slightly vibrant, deeper croaked kraa is distinct from any note of the rook.

The carrion crow is noisy, perching on a vantage point such as a building or the top of a tree and calling three or four times in quick succession, with a slight pause between each series of croaks. During each series of calls, a crow may perform an accompanying gesture, bowing its head and neck downwards with each caw. The wing-beats are slower, more deliberate than those of the rook.

Carrion crows can become tame near humans, and can often be found near areas of human activity or habitation including cities, moors, woodland, sea cliffs and farmland where they compete with other social birds such as gulls and ducks for food in parks and gardens.

Like all corvids, carrion crows are highly intelligent, and are among the most intelligent of all animals.

Like other species of corvid, carrion crows will actively harass predators and competitors that enter their territory or threaten them or their offspring, and will engage in group mobbing behaviour as a method to defend themselves.

Diet
Though an eater of carrion of all kinds, the carrion crow will eat insects, earthworms, grain, fruits, seeds, small mammals, amphibians, scraps and will also steal eggs. Crows are scavengers by nature, which is why they tend to frequent sites inhabited by humans in order to feed on their household waste. Crows will also harass birds of prey or even foxes for their kills. Crows actively hunt and occasionally co-operate with other crows to make kills, and are sometimes seen catching ducklings for food.

Nesting
The bulky stick nest is usually placed in a tall tree, but cliff ledges, old buildings and pylons may be used as well. Nests are also occasionally placed on or near the ground. The nest resembles that of the common raven, but is less bulky. The 3 to 4 brown-speckled blue or greenish eggs are incubated for 18–20 days by the female alone, who is fed by the male. The young fledge after 29–30 days.

https://en.wikipedia.org/wiki/Carrion_crow