In flight, the Carrion Crow has a shorter head than the Rook, as well as having slower wing beats. The tail is squarer in the Carrion Crow, and the "fingers" at the wing tips are less splayed.
The Hooded Crow is the same species as the Carrion Crow but is a different race, which can be mostly found in Ireland, Scotland and the Isle of Man, though some wintering continental birds may be seen in eastern England. The Hooded Crow has a grey back and underparts and a black hood, wings and tail. The Hooded Crow is the main race in Ireland.
Juvenile Carrion Crows have duller, browner plumage and pale blue eyes; the adults have brown eyes.(LINK)