Rook

Description

The rook (Corvus frugilegus) is a member of the family Corvidae in the passerine order of birds. It is found in the Palearctic, its range extending from Scandinavia and western Europe to eastern Siberia. It is a large, gregarious, black-feathered bird, distinguished from similar species by the whitish featherless area on the face. Rooks nest collectively in the tops of tall trees, often close to farms or villages, the groups of nests being known as rookeries. Rooks are mainly resident birds, but the northernmost populations may move southwards to avoid the harshest winter conditions. The birds form flocks in winter, often in the company of other Corvus species or jackdaws. They return to their rookeries and breeding takes place in spring. They forage on arable land and pasture, probing the ground with their strong bills and feeding largely on grubs and soil-based invertebrates, but also consuming cereals and other plant material. Historically, farmers have accused the birds of damaging their crops, and have made efforts to drive them away or kill them. Like other corvids, they are intelligent birds with complex behavioural traits and an ability to solve simple problems. The rook is a fairly large bird, at 280 to 340 g (9.9 to 12.0 oz) adult weight, 44 to 46 cm (17 to 18 in) in length and 81 to 99 cm (32 to 39 in) wingspan. It has black feathers that often show 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, the bill grey-black and the iris dark brown. In adults, a bare area of whitish skin in front of the eye and around the base of the bill is distinctive, and enables the rook to be distinguished from other members of the crow family. This bare patch gives the false impression that the bill is longer than it is and the head more domed. The feathering around the legs also appears shaggier and laxer than the similarly sized carrion crow, the only other member of its genus with which the rook is likely to be confused. Additionally, when seen in flight, the wings of a rook are proportionally longer and narrower than those of the carrion crow. The average lifespan is six years. The juvenile plumage is black with a slight greenish gloss, except for the hind neck, back and underparts, which are brownish-black.