The American mink was first imported to Great Britain in 1929 for fur farming, though a series of escapes and releases lead to the establishment of a self-sufficient feral population in Devon by the late 1950s, and others by the early 1960s. Mink numbers have increased rapidly in the last 30-40 years, and they are now common and widespread. They are semi-aquatic and are frequently encountered on our canals and rivers.
Close up, American mink resemble something between a small cat and a ferret. They have a dense coat of deep brown fur, which often leads to cases of misidentification with the native otter. However, otters are shy animals unlikely to be seen during the day – quite unlike their confident American cousins who will wander the waterways at all hours.
Mink are also smaller and slimmer than otters, which makes it easier for them to hunt burrow-dwelling prey such as water voles. In the UK, the water vole has been in decline since the beginning of the twentieth century, due to habitat loss, degradation and fragmentation. However this decline accelerated sharply throughout the 1960s and 1970s, coinciding with the spread of American mink in the wild.
Unless some areas are kept free or relatively free of mink, it is considered that the water vole will become extinct in much of Britain within a few years. The urgency of the situation is highlighted by the water vole’s inclusion as a priority species in the UK Biodiversity Action Plan and the promotion of humane mink control as an essential tool in water vole conservation, within the National Species Action Plan.