Rook

Rooks are not unlike crows in appearance, but there is one virtually infallible way of telling them apart. If you see a single rook, it’s a crow, and if you see lots of crows, they’re rooks! Indeed, rooks are notorious for gathering in large numbers, and they can offer a spectacular sight in winter as they assemble in flocks when ready to roost.

  

Appearance

The rook (Corvus frugilegus) is of similar size to the (carrion) crow at 46 centimetres (18 inches) long, but smaller than the raven and larger than the jackdaw, these being the other main members of the corvus family to be seen in the United Kingdom.

The rook is glossy black with traces of purple and green. It has a slender, pointed, light-coloured bill and a patch of white skin on the face. The head has a distinct peak, and the upper legs are covered by loose feathers that give the impression that the bird is wearing a pair of baggy shorts. Males and females have similar plumage.

Behaviour

In flight, rooks are notable for their rounded tails and backswept “hands”. Sometimes they fly with rapid wing-beats and at other times they glide, tumble, roll and dive. On the ground they walk or hop.

The voice is a loud cawing sound that is often heard in chorus, at a higher pitch than that of the crow.

Rooks are birds of the open countryside, found in all parts of the United Kingdom except the far north and west of Scotland. They can often be seen feeding in groups in fields, and will associate with jackdaws in joint flocks.

Breeding

In early spring the large flocks tend to split up to form smaller “rookeries” in the tops of mature trees. The nests, comprised of twigs, are a familiar sight, especially in dead trees or when the foliage has fallen in autumn. Rooks often re-use old nests, making repairs when necessary.

The clutch comprises four or five eggs, incubated by the female alone for around 18 days when she is brought food by the male. When the chicks hatch, the male rook is at first the sole provider of food, but after a few days the female rook joins him in this task. Only one brood is raised in a season.

The food brought to the nest is mostly insects, but the food of the adult rook is much more varied, with the diet including seeds, berries, worms, molluscs, and food taken from local fields such as root crops and corn. The “scarecrows” seen in many bare fields should more properly be called “scarerooks”, because that is the bird that is more likely to cost the farmer money!

© John Welford