Gordon Buchanan can't say no to a ride in a police car to go looking for wildlife. Some unusual foreign immigrants have taken up residence near St Ives in Cornwall, and policeman Paul Freestone knows just where to find them. Cattle egrets are usually associated with the Americas, Africa, Australasia and Southern Europe, but they are not a common sight in the UK. They usually feed on the insects kicked up by moving herds of antelope or elephants, but here in the UK they are following the dairy herd for much the same reason. There are two trains of thought as to why these birds might be here, one is that these birds are from the continent where their breeding range is gradually becoming more northern, or alternatively they may be American birds that have come across to the UK on their migration, with the wind in the right direction. In the past only small numbers of these birds have turned up in Britain and the chances of the species colonising have been remote, but now these Cornish birds are in breeding plumage, with tawny coloured feathers on their heads, back and chest. And they’re in such large numbers it's just possible they might nest here.