American mink – the mustelids escaped from fur farms who have decimated populations of water voles and other native birds, fish and amphibians – have been eradicated from a swath of East Anglia.
Until now, mink have never been successfully removed from any large area of Britain but the success of a trial using drops from the invasive predator’s pungent anal scent gland to lure animals into hundreds of traps raises hopes that the species can be eradicated from the whole country.
After four years of trapping using 441 “smart” traps, monitoring confirmed that there had been no evidence of mink reproduction in 2023 across central and eastern Norfolk and Suffolk, an area of 5,852 sq km, almost 5% of England.
This “core area” was protected with further traps across a 60km-wide “buffer zone” that prevented mink from entering from the west and south.
The mink eradication trial was devised in 2019 by a coalition of conservation charities and water management organisations, a partnership that led to the creation of conservation charity the Waterlife Recovery Trust.
Prof Tony Martin, the chair of the WRT and a global expert in eradicating non-native predators for the benefit of native wildlife, said: “Until now, the complete removal of American mink from Britain has been an impossible dream, but the success of this trial offers hope that a century of catastrophic damage to precious native wildlife can be brought to an end.
“It’s now a race against time to eradicate mink before they wipe out the last of our water voles and drive the final nail into the coffin of seabird colonies already hammered by avian influenza.”
Populations of water voles in Britain have declined by 96% since 1950, driven by habitat loss but also the spread of non-native mink, for whom the voles are easy prey.
Coastal seabird colonies within swimming range of the amphibious mink have also suffered severe losses of adult birds and chicks to the North American mustelid.
Although releases of American mink from fur farms by animal rights activists garnered much publicity in the 1990s, mink had established themselves in the wild in the 1950s, escaping from some of the 400 fur farms in Britain.
Mink have been removed from small areas in the past but have rapidly recolonised as soon as trapping stops. But there are hopes this more efficient method carried out at scale will be more sustainable.
The WRT team, including hundreds of volunteers, exploited the mink’s keen sense of smell by suspending hollow practice golf balls inside each trap. These contained cigarette filters with one to two drops from the mink’s anal scent gland, harvested from previously caught mink, which successfully lured other mink.
The smart traps alerted their managers by text and email when the door closed, promoting a rapid response that improves animal welfare and reduces the need to check the traps every day.
Dr Julie Hanna, a species conservation adviser for Natural England, the government’s wildlife watchdog, which supported the trial, said: “The trial results are encouraging and we hope will help recover water vole populations, and benefit other species which have been affected by American mink.
“Species conservation strategies are a new provision under the Environment Act 2021 which will contribute to meeting the government’s legally binding targets to halt species decline.”
