This species is similar in size (45-47 cm in length) to or slightly smaller than the Carrion Crow with black feathers often showing a blue or bluish-purple sheen in bright sunlight. The feathers on the head, neck and shoulders are particularly dense and silky. The legs and feet are generally black and the bill grey-black. Rooks are distinguished from similar birds of the crow family by the bare grey-white skin around the base of the adult’s bill in front of the eyes. They have feathers around the legs which look shaggier and laxer than the Carrion Crow. The juvenile is more similar to the Crow because it lacks the bare patch at the base of the bill, but it has a thinner bill.
Habitat and Distribution
Though resident in Great Britain, Ireland and much of north and central Europe, vagrant to Iceland and northern Scandinavia, it also occurs as an eastern race in Asia. In the north of its range the bird moves south during autumn. The Rook has been introduced to New Zealand. There the species is an agricultural pest.
Food is mainly earthworms and insect larvae, found by probing the ground. It also eats cultivated cereal grain, smaller amounts of fruit, small mammals, acorns, small birds, their eggs and young.
They nest usually in the very tops of trees. Branches and twigs are broken off trees (very rarely picked up off the ground), many though are likely to be stolen from nearby nests. Eggs are usually 3-5 in number, can appear by the end of February or early March and are incubated for 16-18 days. Both adults feed the young, which are fledged by the 32nd or 33rd day.
Calls and Songs
The call is usually described as “kaah”. It is given both in flight and while perched.