There are a few species of birds that are doing extremely well in britain. The biggest winners, at least in proportionate terms, are all, in some sense, immigrants. Little egrets seem to have spread northwards from france, and they hav heve gradually spread through bittain. Red kites used to be very, very common, but they had almost been completely exterminated. They were carefully reintroduced to southern england beginning in 19 90,. These days, if you look up in many parts of southern england, you will see a red kite. Nd they have a sort of forked tail. Ring necked parakeets have been