Conservationists working to bring back threatened water voles to the River Crane nature reserve fear their work is threatened by mink.

One of the non-native wild animals was recently spotted close to the Little Park area, which is on the north-west side of the Hanworth Road (A314) between the two branches of the River Crane.

The distinctive brown mink, which are typically a little over two feet long, are known to target water voles and ducks.

American mink were first brought to Britain in 1929 where they were bred on commercial fur farms.

Water voles are threatened by mink (Credit FoRCE)

A number escaped or were deliberately released in the 1960s and they now breed and live wild in many locations across the country.

Some water voles currently live on Crane island, while a team, including the Friends of the River Crane Environment group (FoRCE) together with experts from Richmond Borough Council are currently working to release more into the area.

Rob Gray, a FoRCE trustee, told Nub News: "Our big fear would be for the loss of the last few remaining water voles on Crane Park Island. 

"We will be doing a full survey for them in the next month and will know more then."

He added: "Only the one mink has been spotted … hopefully it has passed through quickly."

He asked visitors to the area to report any new sightings of the mink to [email protected]

Council sources said mink are a very effective predator of the protected water voles. Even one of the animals can kill a number of voles in a short period.

Mink traps have been set up in the park since April 2022 and, to date, none have been captured.

There are hopes that the sighting of the mink will not affect plans for a major water vole release in the area.

A Council spokesperson said: 'The Council will work with conservation specialists on the release of the water voles.

' This is currently planned for late spring 2024, but we continually monitor the environment to make sure it will provide quality habitat for the voles. This includes monitoring the mink situation, so we are asking local residents to report any sighting to the Friends of the River Crane Environment.'