Alien invaders: American mink removed from Scotland
1 February 2011 Last updated at 05:43 GMT
Scientists have carried out one of the largest ever eradications of an invasive species - the American mink.
The predator first arrived in the UK in the 1950s from America to be farmed for its fur.
But when some escaped - or were released - they spread across the whole country and have had a devastating effect on local wildlife.
Now conservationists have cleared 10,000 sq km of land in north-east Scotland of mink.
Here, biologist Jamie Urquhart from the River Don Trust shows science reporter Rebecca Morelle how the mink are caught.