Apart from the Raven, the Carrion Crow ( Corvus corone) is Britain's largest crow. At first glance they look very similar to Rooks, apart from the white patch. Once you become more familiar with them, it is possible to see they are slightly larger, heavier and have a slightly different posture. You will also very often find them alone. The smaller birds next to this one are Jackdaws.
A group of Carrion Crows is either a Coven or a Murder of Crows.
To see the rest of this coven of crows just follow the links...