The Carrion Crow is usually fully black, unlike the Hooded Crow, and has sleeker/tidier plumage than a Rook, with a black beak on a fully feathered face.
Like all corvids, it is intelligent for a bird. Experiments have included seeing it drop stones into a narrow beaker of shallow water to raise the water level to reach a floating morsel of food.
Crow doing an impression of a Rook with shaggy feathers and angular shape.
Unlike gregarious Rooks, which nest in communal Rookeries, Crows of breeding age tend to be solitary or in pairs but may form flocks in winter. Juveniles under 3 years and elders over 7 also tend to form flocks, and breeding crows will gang together to chase off intruders such as birds of prey (they will bravely peck at heads of birds of prey until the raptor leaves the area).