American mink have been in the news as a disease vector for COVID-19. Millions of animals on hundreds of Danish fur farms are to be destroyed.
Many people think that the UK’s wild population of American mink originated from mass releases from fur farms by animal rights activists in the 1990s. Thousands of animal were released and the incidents received widespread publicity but the American mink had been established in the wild for many years before that.
There had been mink farms in Britain since the 1920s. At its peak in the 1950s, there were over 400 fur farms in the UK and, of course, there were escapes: mink were first confirmed to be breeding in the wild in 1956. By December of 1967, wild mink were present in over half the counties of England and Wales, and in much of lowland Scotland.
American mink prey species:  water vole;  common frog;  grass snake.
Mink are carnivores, voracious hunters that have damaged native riparian wildlife and are believed to be responsible for the near-extinction of water voles. Unlike native predators, a mink is both a strong enough swimmer to catch a water vole in the water, and small enough to follow it down into its hole if it escapes.
The Lambrok is mink-free at the moment, which may be one reason for the stream’s rich biodiversity. We keep vigilant watch and would call in the trappers at the first signs. However there is good news.
Research has found that, for the first time in 40 years, otters are displacing American mink along our river banks. In rare cases, otters are even known to have killed mink in fights over territory. As otter numbers recover, mink numbers are falling dramatically. From a nationwide peak of an estimated 110,000 mink in the 1980s, mink numbers could now be as low as 40,000.
The otters in Lambrok Stream will help us protect the park’s wildlife from one of the UK’s most dangerous invasive species. We need to make sure that the housing developments planned for Church Lane, Upper Studley and Southwick Court do not damage the otters’ habitat or cut them off from this part of their range.
The Lambrok Stream is a complex and important biosphere, supporting apex predators that are protecting it from dangerous invasive aliens; let’s keep it that way.