American mink
 

Mustela vison  

The American Mink is a member of the weasel family (mustelidae) and a relative of stoats, otters, polecats and badgers. They are not native to Britain but were brought here from north America in 1929 to be bred commercially for their fur. There have probably been escapee mink in the wild since that time. The first confirmation of breeding mink in the wild was in South Devon in 1956. Mink are now present on virtually every waterway across Britain. However, over the last 10 years, populations have declined substantially and there are now an estimated 18,000 in England and Wales.

Mink look like a cross between a small black cat and a ferret. They have shiny chocolate-brown fur and a slightly bushy tail, which makes up about half of their body length. They are distinguished from the European Mink (Mustela lutreiola) by having a small amount of white confined to the lower lip. They are active both day and night and are commonly found living on riverbanks. They make their nests in existing burrows by the waterside often among tree roots, or in old rabbit burrows. Adult male mink weigh about 1.2kg and are about 60cm from their noses to the tip of their tail. Female mink are smaller.

PREDATORS

The mink has no natural predators in Britain, although evidence from the faeces of otters suggests they may fall victim to otters on occasion. Their territorial behaviour and aggressiveness to their own kind ensures they always remain at a low population density. Mink are an opportunist predator, taking a wide range of small mammals, fish, birds and invertebrates. Males will not tolerate other males within their range. When one is removed, another quickly occupies the vacant area.

LIFESPAN

Mink breed once a year, with five or six kits born in early May in underground dens. Young mink are weaned at seven weeks. They are very agile climbers and swimmers. They have a very well developed sense of smell which they use to locate their prey and sense danger. American Mink can live to be up to eight years old, but few survive beyond their second year.