It would be hard to confuse the collared dove (Streptopelia decaocto) with anything else although I have heard people refer to them as ringed doves which are actually a totally different non-British species. Until the early 1950's the collared dove was a non-British species too, being more at home in the Balkans. During the 1930's it suddenly began to spread across Europe and arrived in Britain in 1954 (as far I can ascertain). Its arrival had the 'twitchers' of its day quite excited but now it is just a common bird seen near human habitation from farms to city centres right across the United Kingdom. It is currently number 7 in the top twenty garden birds having first entered the top 10 at number 10 in 1989. The meteoric rise up the charts has pretty well ceased now and it seems to have found its level and recently there may be signs that it is in decline.
Of all garden birds, this is the one almost always is seen in pairs, no matter what time of year; when one flies in you can be pretty sure its mate will not be far behind. The fact that they are usually in pairs and that they breed for nine months of the year feeding one lot of young whilst brooding the next clutch of eggs must indicate that it is likely they mate for life. Even as early as January the prelude to another years frantic family life starts with the male emitting its monotonous "united, united, united" song. They are lovely together though aren't they, the perfect loving couple!Collared Dove: united and together