Rook (Corvus frugilegus)

GenusCorvus (1)
SizeLength: 41-49 cm (2)
Wingspan: 81-94 cm (2)

The rook is classified as Least Concern (LC) on the IUCN Red List (1). Receives general protection under the Wildlife and Countryside Act 1981 (3). Included in the Birds of Conservation Concern Green List (low conservation concern) (4).

The rook (Corvus frugilegus) is the same size as carrion and hooded crows (Corvus corone, and C. cornix respectively). It has black plumage with a red-lilac gloss (2). Adults have a bare area of whitish-grey skin at the base of the bill, and a slightly 'peaked' crown (2). Immature rooks look very similar to carrion crows, especially as they have facial feathers and nasal bristles (5), however they can be identified by their straighter, more pointed bill (2). Vocalisations are hoarse and 'grinding' and a tremendous cacophony can be produced from large rookeries (2).

The range of the rook extends throughout Europe and Asia; in Britain it is very widespread (6).

The rook occupies agricultural land below 300 metres, and seems to prefer farms with both pasture and arable areas (6).

Rooks are omnivorous; they eat a very broad range of food, including earthworms and other invertebrates (2), seeds and waste root crops in winter (6). They feed on the ground, often inserting the beak into the soil, and may bury food for consumption at a later time (5).

This bird is very sociable, and nests communally in groups of trees known as 'rookeries' (5). Communal roosts form in winter, consisting of birds from a number of breeding rookeries (6). These roosts can be huge; one in northwest Scotland contained 65,000 rooks (6). By February, the rooks return to their own rookery in order to start breeding (6); pairs defend a small area around their nests. During courtship, the male struts around, bowing, posturing and cawing; he may then empty the contents of his food pouch into the female's mouth before mating takes place (5). The nest is constructed of twigs, and three to five blue or grey-green eggs are laid towards the end of March. These are incubated by the female for up to 18 days; whilst the female incubates the eggs and broods the chicks she is fed by the male (5). After 40 days, the chicks are fully grown, but they remain dependent on their parents for food until they reach 60 days of age, and only become truly independent after around five months (5).

Like many members of the crow family, the rook figures heavily in folklore. The sudden desertion of a rookery was said to be a bad omen for the landowner. Rooks are believed to indicate rain by certain behaviour (7), and are also believed to be able to smell approaching death (5).

This is one of the most common agricultural birds, yet, like many of its relatives, the rook has suffered persecution at the hands of farmers, gamekeepers and landowners for many hundreds of years, as it is perceived as a pest. Organochloride chemicals are also known to affect this species (5).

No specific conservation action is targeted at the rook, but it should benefit from work for farmland birds in general, such as agri-environment schemes (8).

For more information on the rook:

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Information authenticated by the RSPB:

  1. IUCN Red List (April, 2011)
  2. Mullarney, K., Svensson, L., Zetterstrom, D., & Grant, P.J. (1999) Collins Bird Guide. HarperCollins Publishers Ltd, London.
  3. Naturenet (July 2002):
  4. RSPB (2003) The population status of birds in the UK
  5. Bruce Wilmore, S. (1977) Crows, jays, ravens and their relatives. David and Charles (Publishers) Ltd, London.
  6. Lack, P. (1986) The Atlas of Wintering Birds in Britain and Ireland. T. & A. D. Poyser Ltd, Calton.
  7. Greenoak, F. (1979) All the birds of the air; the names, lore and literature of British birds. Book Club Associates, London.
  8. RSPB (2003) Pers. comm.