(Corvus frugilegus), a bird of the family Corvidae of the order Passeriformes. The body is about 44 cm long. The feathers are black with a blue-violet cast. In adult birds the skin at the base of the beak is bare. Rooks are distributed in central Europe and Asia. In the USSR they are known south of the line Arkhangel’sk-Yakutsk; they are numerous only in agricultural regions. The rook is a migratory bird; it winters in the southern European part of the USSR and in Middle Asia. It arrvies at the nesting sites in March and leaves in October-November. The birds nest in colonies in high trees. They are very useful in destroying various pest insects, but during crop sowing they may harm sowings of grain, grape, and vegetable crops, because they peck out the seeds and shoots.