Rook
The Rook is a passerine bird in the crow family Corvidae. It is a fairly large bird at 18 to 19 inches in length with black plumage that often shows a blue or bluish-purple sheen in bright sunlight. The feathers on the head, neck and shoulders are particularly dense and silky. The legs and feet are generally black, the bill grey-black and the iris dark brown. In adults, a bare area of whitish skin in front of the eye and around the base of the bill is distinctive and enables the Rook to be distinguished from other members of the crow family. This bare patch gives the false impression that the bill is longer than it is and the head more domed. The feathering around the legs also appears shaggier than the similarly sized Carrion Crow, the only other member of its genus with which the Rook is likely to be confused. Additionally, when seen in flight, the wings of a Rook are proportionally longer and narrower than those of the Carrion Crow. The juvenile plumage is black with a slight greenish gloss except for the hind neck, back and underparts which are brownish-black. The juvenile is superficially similar to a young Carrion Crow because it lacks the bare patch at the base of the bill but it has a thinner beak and loses the facial feathers after about 6 months.
The Rook is resident in the UK and much of north and central Europe but it is a vagrant to Iceland and parts of Scandinavia where they typically live south of latitude 66° north. In the north of its range the Rook has a tendency to move south during autumn and more southern populations are apt to range sporadically. The Rook is found in habitats such as open agricultural areas with pasture or arable land as long as there are suitable tall trees for breeding. It generally avoids forests, swamps, marshes, heaths and moorland. In general it is a lowland bird with most rookeries found below 400 feet but where suitable feeding habitat exists it may breed at 1000 feet or even higher. The Rook is often associated with human settlements, nesting near farms, villages and open towns but not in large, heavily built-up areas.
The Rook is a very social and gregarious bird and is generally seen in flocks of various sizes. It is a monogamous species with the adults forming life-long pair bonds and pairs stay together within flocks. In the evening, birds often congregate at their rookery before moving off to their chosen communal roosting site. Flocks increase in size in autumn with different groups amalgamating and birds congregating at dusk before roosting, often in very large numbers and in the company of Jackdaws. Roosting usually takes place in woodland or plantations but a small minority of birds may continue to roost at their rookery all winter and adult males may roost collectively somewhere nearby. Birds move off promptly in the morning, dispersing for distances of up to 5 miles or more.
The Rook mostly forages on the ground striding about or occasionally hopping and probing the soil with its powerful beak. Around 60% of the diet is vegetable matter and the rest is of animal origin. Vegetable foods include cereals, potatoes, roots, fruit, acorns, berries and seeds while the animal part is predominantly earthworms and insect larvae. It also eats beetles, spiders, millipedes, slugs, snails, small mammals, small birds and their eggs and young and occasionally carrion. In urban areas, human food scraps are taken from rubbish dumps and streets, usually in the early hours or at dusk when it is relatively quiet. Like other corvids, the Rook will sometimes favour sites with a high level of human interaction and can often be found scavenging for food in tourist areas or pecking open garbage sacks.
The male Rook usually initiates courtship, on the ground or in a tree, by bowing several times to the female with drooping wings and at the same time cawing and fanning his tail. The female may respond by crouching down, arching her back and quivering her wings slightly or she may take the initiative by lowering her head and wings and erecting her partially spread tail over her back. Further similar displays are often followed by begging behaviour by the female and by the male presenting her with food before mating takes place on the nest. A mated pair of rooks will often fondle each other's bills and this behaviour is also sometimes seen in autumn.
Nesting in a rookery is always colonial, usually in the very tops of large trees and often on the remnants of the previous year's nest. In hilly regions, the Rook may nest in smaller trees or bushes and exceptionally on chimneys or church spires. Both sexes participate in nest-building with the male finding most of the materials and the female putting them in place. The nest is cup-shaped and composed of sticks, consolidated with earth and lined with grasses, moss, roots, dead leaves and straw.
The female lays 3 to 5 eggs (sometimes 6 and occasionally 7) by the end of March or early April in the UK and west Europe but in the harsher conditions of east Europe and Russia it may be early May before the clutch is completed. The eggs are incubated for 16 to 18 days, almost entirely by the female who is fed by the male. After hatching, the male brings food to the nest while the female broods the young. After 10 days, the female joins the male in bringing food which is carried in a throat pouch. The young fledge after 32 or 33 days but continue to be fed by the parents for some time thereafter. There is normally a single brood each year but there are records of birds attempting to breed again in the autumn. In autumn, the young birds collect in to large flocks together with unpaired birds of previous seasons and often in the company of Jackdaws. It is during this time of year that spectacular aerial displays are performed by the birds.
Like other corvids, the Rook is an intelligent bird with complex behavioural traits and an ability to solve simple problems.
The Rook has an extremely wide distribution and a very large total population. The main threats it faces are from changes in agricultural land use, the application of seed dressings and pesticides and persecution through shooting. Although the total number of birds may be declining slightly across its range, this is not at so rapid a rate as to cause concern and the IUCN has assessed the bird's conservation status as being of "least concern".
Date: 10th November 2011
Location: Fionnphort, Mull, Argyll
The Rook is resident in the UK and much of north and central Europe but it is a vagrant to Iceland and parts of Scandinavia where they typically live south of latitude 66° north. In the north of its range the Rook has a tendency to move south during autumn and more southern populations are apt to range sporadically. The Rook is found in habitats such as open agricultural areas with pasture or arable land as long as there are suitable tall trees for breeding. It generally avoids forests, swamps, marshes, heaths and moorland. In general it is a lowland bird with most rookeries found below 400 feet but where suitable feeding habitat exists it may breed at 1000 feet or even higher. The Rook is often associated with human settlements, nesting near farms, villages and open towns but not in large, heavily built-up areas.
The Rook is a very social and gregarious bird and is generally seen in flocks of various sizes. It is a monogamous species with the adults forming life-long pair bonds and pairs stay together within flocks. In the evening, birds often congregate at their rookery before moving off to their chosen communal roosting site. Flocks increase in size in autumn with different groups amalgamating and birds congregating at dusk before roosting, often in very large numbers and in the company of Jackdaws. Roosting usually takes place in woodland or plantations but a small minority of birds may continue to roost at their rookery all winter and adult males may roost collectively somewhere nearby. Birds move off promptly in the morning, dispersing for distances of up to 5 miles or more.
The Rook mostly forages on the ground striding about or occasionally hopping and probing the soil with its powerful beak. Around 60% of the diet is vegetable matter and the rest is of animal origin. Vegetable foods include cereals, potatoes, roots, fruit, acorns, berries and seeds while the animal part is predominantly earthworms and insect larvae. It also eats beetles, spiders, millipedes, slugs, snails, small mammals, small birds and their eggs and young and occasionally carrion. In urban areas, human food scraps are taken from rubbish dumps and streets, usually in the early hours or at dusk when it is relatively quiet. Like other corvids, the Rook will sometimes favour sites with a high level of human interaction and can often be found scavenging for food in tourist areas or pecking open garbage sacks.
The male Rook usually initiates courtship, on the ground or in a tree, by bowing several times to the female with drooping wings and at the same time cawing and fanning his tail. The female may respond by crouching down, arching her back and quivering her wings slightly or she may take the initiative by lowering her head and wings and erecting her partially spread tail over her back. Further similar displays are often followed by begging behaviour by the female and by the male presenting her with food before mating takes place on the nest. A mated pair of rooks will often fondle each other's bills and this behaviour is also sometimes seen in autumn.
Nesting in a rookery is always colonial, usually in the very tops of large trees and often on the remnants of the previous year's nest. In hilly regions, the Rook may nest in smaller trees or bushes and exceptionally on chimneys or church spires. Both sexes participate in nest-building with the male finding most of the materials and the female putting them in place. The nest is cup-shaped and composed of sticks, consolidated with earth and lined with grasses, moss, roots, dead leaves and straw.
The female lays 3 to 5 eggs (sometimes 6 and occasionally 7) by the end of March or early April in the UK and west Europe but in the harsher conditions of east Europe and Russia it may be early May before the clutch is completed. The eggs are incubated for 16 to 18 days, almost entirely by the female who is fed by the male. After hatching, the male brings food to the nest while the female broods the young. After 10 days, the female joins the male in bringing food which is carried in a throat pouch. The young fledge after 32 or 33 days but continue to be fed by the parents for some time thereafter. There is normally a single brood each year but there are records of birds attempting to breed again in the autumn. In autumn, the young birds collect in to large flocks together with unpaired birds of previous seasons and often in the company of Jackdaws. It is during this time of year that spectacular aerial displays are performed by the birds.
Like other corvids, the Rook is an intelligent bird with complex behavioural traits and an ability to solve simple problems.
The Rook has an extremely wide distribution and a very large total population. The main threats it faces are from changes in agricultural land use, the application of seed dressings and pesticides and persecution through shooting. Although the total number of birds may be declining slightly across its range, this is not at so rapid a rate as to cause concern and the IUCN has assessed the bird's conservation status as being of "least concern".
Date: 10th November 2011
Location: Fionnphort, Mull, Argyll
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Also in: Crows
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