Breeding birds: 1,100,000 pairs
Rooks have black plumage with some blue and purple gloss on the wings. They differ from crows by a bare patch of skin around their bills.
Rooks have pointed bills that curve downwards slightly. Due to the lack of nostril bristles, their nostrils are visible. Rooks’ eyes are dark brown and their legs and feet are dark grey.
Adult male and female rooks look similar while juveniles are duller with a fully feathered face. They acquire the bare patch when they are about a year old.
Rooks nest in a colony called a rookery with nests placed high up in trees. Both male and female build the nest which is constructed from twigs and sticks. It is lined with roots, grass and leaves. Nests may be repaired and used for a number of years.
Rooks lay 2-7 blue or greyish-green eggs with dark spots. The female incubates the eggs for 16-18 days. Chicks are fed by both parents and they fledge at 30-35 days after hatching. Both parents will continue to feed the chicks for another 6 weeks.
Rooks are omnivorous and will eat worms and beetles but also small mammals, frogs and the eggs and nestlings of other bird species. In the autumn and winter they will supplement their diet with grain, seeds and berries. In winter they will often feed in flocks with jackdaws.
Rooks can be seen all year round all over the UK except for the very north of Scotland. They are usually seen in flocks in open fields and by the side of roads but will also come into parks and villages.
Rooks are one of the few birds who have been documented using tools to solve problems and appear to have an awareness of gravity comparable with a 6-month old baby.