The plumage of the 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. 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. Juvenile Carrion crows can be identified by their brownish plumage and blue eyes, both of which darken to black and brown as the crow grows older.
Carrion crows are native to western Europe and much of Asia. Birds that live in colder areas may migrate south to spend the winter months. Carrion crows live in a variety of habitats including parks and gardens, cultivated areas, wetlands, forest clearings, woodlands, moors, inshore islands, coastal cliffs, and tidepools.
Carrion crowns are generally solitary but may feed in groups and are often sociable in winter roosts. They are noisy birds, 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, raising its shoulders and bowing its head and neck downwards with each caw. Carrion crows are scavengers by nature, which is why they tend to frequent sites inhabited by humans in order to feed on their household waste. They will also harass birds of prey or even foxes for their kills. Carrion crows actively hunt and occasionally co-operate with other crows to make kills, and are sometimes seen catching ducklings for food. Due to their gregarious lifestyle and defensive abilities, Carrion crows have few natural predators. They will actively harass predators and competitors that enter their territory or threaten them or their offspring and will engage in group mobbing behavior as a method to defend themselves.
Carrion crows are scavengers and omnivores. They primarily feed on carrion of all kinds, but will also eat insects, earthworms, grain, fruits, seeds, small mammals, amphibians, scraps, and will also steal eggs.
Carrion crows are monogamous and form long-lasting pair bonds. Their breeding season varies according to location and typically occurs between March and early June. Both adults build the bulky stick nest which is usually placed in a tall tree, but cliff ledges, old buildings, and pylons may be used as well. Nests may also be occasionally placed on or near the ground. The female lays 3 to 4 brown-speckled blue or greenish eggs and incubates them alone for 18-20 days. During this time she is fed by the male. Both parents feed and defend their newly hatched helpless chicks which fledge after 29-30 days. It is not uncommon for offspring from the previous years to stay around and help rear the new hatchlings. Instead of seeking out a mate, it looks for food and assists the parents in feeding the young.
There are no major threats to the Carrion crow at present.
According to the IUCN Red List, the total population size of the Carrion crow is 58,700,000-111,000,000 mature individuals. In Europe, the breeding population consists of 8,790,000-16,600,000 pairs, which equates to 17,600,000-33,300,000 mature individuals. Currently, this species is classified as Least Concern (LC) on the IUCN Red List, and its numbers today are increasing.