Birds on the Brink. The ruddy duck is an escaped North American bird which is about to be exterminated in the UKfor being too successful and hybridising with rare Spanish white-headed ducks. The eagle owl is an escapee now breeding in very small numbers in the wild in Britain, but may never have lived here. And the great bustard is a species which we wiped out centuries ago, but which we're planning to bring back. Nature assesses our differing attitudes to these British birds and explores their futures through the eyes of conservationists. Producer Paul Evans Repeated tomorrow at 11am