Mink are small carnivores of the mustelid family. They are predators, killing a wide variety of principally water-side animals - anything from small frogs and fish to water voles and moorhens.
The mink found in in Britain is an American species. It was an accidental addition to the British fauna in the 20th century, the result of animals escaping from fur farms in quite a few different regions. Mink are still farmed for fur in other European countries, where escapes still occur, but since 2000 fur-farming has been prohibited in the UK (2002 in Scotland).
Mink were first shown to be breeding in the wild in Britain in the late 1950s, but were very likely established before then. Subsequently, the species has spread along watercourses and along rocky coastlines into almost all of lowland Britain. Despite their recent introduction, mink are now relatively common - unlike some of our native carnivores. In 2000 there were estimated to be roughly 110,000 in Britain - but one should add that there is no easy way to estimate the population!
There is also a European mink (Mustela lutreola), which is similar in appearance but has never occurred in Britain and is actually endangered in continental Europe. So it can be argued that the American mink fits into an ecological niche that was previously vacant in Britain. In its native North America, though, the mink population is supported by the ubiquitous and highly prolific muskrat, its favoured prey. It might be expected that the introduction of a non-native predator without its natural food base would damage our native fauna severely.
Indeed, there is good evidence for this on small offshore islands, where the appearance of mink has been associated with complete nesting failures of colonies of the black-headed gull, common gull, common tern and Arctic tern. Mink are also thought to have been responsible for the disappearance of the moorhen on the Hebridean islands of Lewis and Harris. However, on mainland Britain, populations of moorhen, coot and little grebe - species most likely to have been affected - seem to be holding their own. The most serious effect on the mainland seems to be on the water vole.
Mink are trapped by gamekeepers and fishery managers, since there is no doubt that these animals do serious damage to penned gamebirds, to waterfowl, and to fish in ponds and rivers. Like many carnivores, mink will indulge in mass kills if they can access penned birds or fish in ponds. However, the main interest in controlling or eradicating mink comes from conservationists concerned for native species in decline.
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