The crow is a large, black bird, approximately 47 cm (18½") in length. There is often confusion between crows and rooks, but crows have a thicker blunter bill, smoother plumage (rooks look ragged in comparison) and lacks the adult rook's bare white face patch. Crows tend to hunt alone or in pairs, unlike the rook's habit of appearing in large flocks. Hence the country saying, "If you see a rook on its own, it's a crow; if you see more than one crow together, they're rooks!"
Where to see it:
As its name suggests, the carrion crow feeds mainly on dead animals and birds, often seen pecking at road kills such as rabbits and hedgehogs, but will also take young or weak fledglings.
Of all birds the carrion crow is the most detested by gamekeepers and country people who rear flocks of poultry, because it is the craftiest of egg thieves. Wild birds also suffer acutely from its depredations. It is the habit of crows to perch like sentinels on the tops of isolated trees, where they can see what is going on in all directions. When birds are building their nests, their activities are observed and remembered by the watching crow, and in due course many nests are wrecked and robbed. Later, when trees are more leafy and it becomes harder for the nests to be spotted, the crow is quick to observe other birds carrying food to their young and again he makes his merciless pounce when all has been discovered; this time he takes the chicks.
The crow's caw is much more harsh and resonant than that of the rook.