Media playback is unsupported on your device

Slimbridge swan project celebrates 50th year

11 February 2014 Last updated at 10:47 GMT

Fifty years ago the conservationist Sir Peter Scott made an historic discovery.

While indulging in his passion for painting and sketching Bewick swans, he noticed that each one had a different face.

His artistic endeavour has become one of the world's longest-running research projects.

John Maguire reports.

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.