The term crow refers to a family of species, of which the raven, jackdaw and rook are a part. To complicate matters, some species within the family are referred to as crows, such as the carrion crow and collared crow. It is easy to get these black birds confused.
The raven, jackdaw and rook are three specific varieties of crows. The raven is the largest. It reaches between 56 and 69 cm in length. It has beautiful iridescent feathers. The jackdaw is much smaller at 34 to 39 cm in length. It has greyish or silver feathers on its neck and cheeks. Another distinguishing feature in the adults is a whitish colour to the eyes. Rooks grow to 45-47 cm in length. They are distinguishable by the bare grey skin around the base of the adult's bill near the eyes. This is visible only in mature crows, because they lose their face feathers in adulthood.
The raven, jackdaw and rook are three specific varieties of crows. The raven is the largest. It reaches between 56 and 69 cm in length. It has beautiful iridescent feathers. The jackdaw is much smaller at 34 to 39 cm in length. It has greyish or silver feathers on its neck and cheeks. Another distinguishing feature in the adults is a whitish colour to the eyes. Rooks grow to 45-47 cm in length. They are distinguishable by the bare grey skin around the base of the adult's bill near the eyes. This is visible only in mature crows, because they lose their face feathers in adulthood.