The Rook is about the same size as the Carrion Crow but is more untidy in its appearance.
The plumage is all black with a reddish or purplish gloss but around the base of its beak - nostrils and chin - is bare skin. The untidy appearance arises from the slightly peaked head and the thigh feathers, which look like baggy trousers. The bill and legs are black.
The Rook's bill is longer and more pointed than that of the Carrion Crow.
Just to add to the confusion, juvenile Rooks do not have the bare skin around the base of the bill and so look very much like a Carrion Crow, but purplish gloss to plumage and baggy trousers remain diagnostic.
Occasionally, leucistic (i.e. pale) Rooks can be seen - these generally have brown plumage or even cream plumage and pink legs and bill.
It is often said that if you see a flock of crows that they will be Rooks. This is not strictly true because Carrion Crows do form flocks, but what is true is that Rooks nest in close-knit colonies but Carrion Crows do not.
| Scientific Name | Corvus frugilegus |
| Length | 45 cm (18") |
| Wing Span | 80-90 cm (32-36") |
| Weight | 460-520 g (1-1¼ lb) |
| Breeding Pairs | 550000 |
| Present | All Year |
| Status | Amber |
Rooks are rarely alone and so their raucous caws can become overwhelming.
The Rook's diet, like most crows, is diverse and includes insects, worms, carrion and seeds. They will visit bird tables for scraps and fruit.
Rooks nest in a colony called a rookery. The nest is built high in a tree close to other nests. The nest is bulky and made from twigs bound together with earth, lined with moss, leaves, grass, wool, hair, etc. Previous years' nests may be renovated and reused.
The hen lays and incubates eggs that are smooth, glossy and light blue, greenish-blue or green with dark spots. The eggs are about 40 mm long. Both parents feed the young after they have hatched.
| Breeding Starts | Clutches | Eggs | Incubation (days) | Fledge (days) |
|---|---|---|---|---|
| March-April | 1 | 3-9 | 16-20 | 30-36 |
Rooks in Britain are mostly sedentary apart from juveniles dispersing from their natal sites, when they may travel up to 100 kilometres (60 miles), and some movement from the uplands to lowlands for the winter.
In the winter, the British population is joined by birds from Scandinavia and the near-continent, such as Germany and Holland.
The Rook seems to be doing well with the population increasing slightly year-on-year and so seems to have adapted to the various changes in agricultural practices that many other species have been adversely affected by.
