Thought you'd like to know that ...
The rose-ringed parakeet,Psittacula krameri, which is native to a great belt of land stretching from Africa across to India and the Himalayas, is the most obvious bird which in Britain today could be seen as invasive and non-native.
No one knows how it came to start breeding in London, although it is certain to have been the result of the accidental or deliberate release of captive birds. One persistent theory is that an entire flock escaped from Shepperton Studios in Surrey in 1951, during the filming of the adventure drama The African Queen, starring Humphrey Bogart and Katherine Hepburn.