Earlier this week a family of mink were spotted on the river. Although very cute these animals cause a major problem to native wildlife.

Originally brought to Britain for fur farming, American mink (Neovision vison) entered the countryside from 1950 by accidental escape or deliberate release by animal rights activists. The effect was a massive decline in water vole populations and ground nesting birds.

Mink are generalist predators, meaning they’ll eat anything meaty they can get their paws on. This means they aren’t reliant on one source of prey so once they’ve caused a decrease in one prey type they move on to another, leading to a decrease in that prey type. This means they themselves don’t suffer from a decrease in a particular prey type, so the mink population can continue to rise whilst many species that make up their prey decrease.

Water voles (Arvicola amphibious) are Britain’s fastest declining wild mammal, with worst case calculations putting their decline at around 95% and extinction looming. American mink have been identified as the main cause of this decline, with habitat loss being another concern.

New evidence suggests things may be improving. Mink don’t like to live in areas where otters are present. This is probably due to competition for food between the two and direct aggression. In areas where otters have increased, mink numbers have decreased and with otter populations on the rise this is hopefully a pattern that will continue.

Click here to find out more about mink and the devastating effect they have on our native wildlife and what’s being done to stop them.

Rhian (Seasonal Ranger)