Stock Dove
Columba oenas

Stock Doves are a close relation of the Wood Pigeon and Rock Dove. They are fairly small and overlap in size with the Rock Dove (and of course the Feral Pigeon) at 32-34 cm in length (compared to 31-35 cm for the Rock Dove). Their plumage is a distinctive light blue-grey with a few dark patches on the wing instead of the wing bars seen on the other two species. They also lack the Wood Pigeon's white collar. Another useful trait is the eye colour - Stock Doves have dark irises, while Wood Pigeons have white and Rock Dove/Feral Pigeons have red. They are fairly common in Britain with more than 300,000 birds present, which now makes them more populous that the wild Rock Dove, although the Feral Dove and Wood Pigeon populations dwarf both. Their call is a deep "oo-woo", different from the other two species. Their diet is mainly seeds and grains.
 

1: Mansbridge, Southampton, 30/04/2013.
2-3: Mansbridge, Southampton, Hampshire, 28/03/2013.