Lots of people keep pigeons either because of their beautiful looks (Fancy Pigeons) or because of the Pigeons ability to return home from afar (Homing Pigeons). Many of these pigeons escaped and mixed with pigeons that lost their way to create a new species: the Town Pigeon. Thus we have no idea whether the one in the picture is such a Town Pigeon or if it is a resting Homing Pigeon.
Homing-pigeons appear regularly in most people's gardens: just resting, completely lost or whatever. Besides the homers there is also a kind of pigeon now known as feral pigeons. You will find them in all cities in Europe. They feed on whatever people give them and often become a pest. Both the city-pigeon and the homer are not directly related to the common Woodpigeon as one might expect as the similaraties are striking. No, it is assumed that the ancestor is the Rock Dove, a bird that can be found in Southern Europe and the Middle East mainly, but in northern parts of Scotland and Ireland as well.