Rooks are mainly resident birds, but the northernmost populations may migrate southwards to avoid the harshest winter conditions.

They forage on arable land and pasture, probing the ground with their strong bills and feeding largely on grubs and soil-based invertebrates, but they also consume cereals and other plant material.

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.

The feathering around the legs also appears shaggier and laxer than the similarly sized carrion crow, the only other member of its genus with which the rook is likely to be confused.

[11] 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 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 six months.

[9] Western rooks are resident in Ireland, Britain and much of north and central Europe but vagrant to Iceland and parts of Scandinavia, where they typically live south of 60° latitude.

They are found in habitats that common ravens dislike, choosing open agricultural areas with pasture or arable land, as long as there are suitable tall trees for breeding.

Rooks are often associated with human settlements, nesting near farms, villages and open towns, but not in large, heavily built-up areas.

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.

[14] Foraging mostly takes place on the ground, with the birds striding about, or occasionally hopping, and probing the soil with their powerful beaks.

In the autumn, flocks sometimes perform spectacular aerial group flights, including synchronised movements and individual antics such as dives, tumbles and rolls.

Vegetable foods include cereals, potatoes, roots, fruit, acorns, berries and seeds while the animal part is predominantly earthworms and insect larvae, which the bird finds by probing the ground with its strong bill.

[9] In urban sites, 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, rooks 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.

[9] Further similar displays are often followed by begging behaviour by the female and by the male presenting her with food, before coition takes place on the nest.

The nest is cup-shaped and composed of sticks, consolidated with earth and lined with grasses, moss, roots, dead leaves and straw.

After a series of poor harvests in the early 1500s, Henry VIII introduced a Vermin Act in 1532 "ordeyned to dystroye Choughes (i.e. jackdaws), Crowes and Rokes" to protect grain crops from their predations.

[28] Francis Willughby mentions rooks in his Ornithology (1678): "These birds are noisome to corn and grain: so that the husbandmen are forced to employ children, with hooting and crackers, and rattles of metal, and, finally by throwing of stones, to scare them away.

"[29] He also mentions scarecrows "placed up and down the fields, and dressed up in a country habit, which the birds taking for countrymen dare not come near the grounds where they stand".

[29] It was some time before more observant naturalists like John Jenner Weir and Thomas Pennant appreciated that in consuming ground-based pests, the rooks were doing more good than harm.

[29] Rookeries were often perceived as nuisances in rural Britain, and it was previously the practice to hold rook shoots where the juvenile birds, known as "branchers", were shot before they were able to fly.