Introduced by Peter Scott
Every autumn wild Bewick's swans leave their breeding grounds in Arctic Siberia - home of polar bears and reindeer, of snowy owls and Arctic foxes - and fly across Europe to winter at Slimbridge on Severnside.
From the studio window of his home at the Wildfowl Trust, Peter Scott looks out on his 'Swan Lake,' while concealed cameras bring into close-up the way in which each individual bird can be identified.
(from Bristol)