Water voles thrive again on the Thaw

Monday, 16 June 2025 15:28

More water voles have been released at the River Thaw in an effort to help bring the UK's fastest declining mammal back to the Vale.

Over 200 captive bred voles were released last August as part of a joint project, marking their return to the river after over 20 years.

They've now been joined by another 140 water voles, who were bed at Natural Resources Wales' hatchery in Cynrig and at the Keep It Wild Trust in Devon.

After spending a few days getting used to their environment in temporary pens, they were let out into the wild in the hope that they'll reinforce the current population and spread out along the river.

While carriyng out a survey along the river, a conservation officer from The Wildlife Trust of South and West Wales heard one vole munching on som vegetation.

Alice Chapman said: "There are so many signs of their activity along the river...look at these footprints and burrows in the banks.”

“It’s rewarding to see these fantastic animals back on the Thaw, not just surviving but thriving, which is testament to the hard work of everyone involved in the partnership.”

Over 90% of all water voles across the UK have disappeared in the last thirty years - a rate described as 'alarming' by wildlife experts, who say predication from the invasive American Mink, along with pollution and habitat degradation is putting them at risk of extinction in Wales.

Extensive work has been undertaken to improve the habitat and eradicate American Mink ready for the release of the second batch of voles.

A team of trained volunteers have been helping to monitor the waterway to see how far the population of water voles has spread.

Melanie Stewart, who manages the Restore the Thaw project, said: "Volunteers are a crucial part of the project, looking out for burrows, footprints, feeding stations and latrines – all signs that we have a growing population of water voles along the Thaw."

NRW says the return of water voles will not only benefit predators such as otters, herons and birds of prey, but their burrowing will help to boost biodiversity in the catchment area and improve the diversity of plants on the riverbanks.

Richard Davies, who is responsible for NRW's breeding programme, added: "I’m really pleased that the water voles we are breeding here are being released onto their new home on the River Thaw as the habitat is excellent."

"There are lots of good sites like this in Wales which would really benefit from having water voles."

The South Wales Rivers Trust, the Initiative for Nature Conservation Cymru, Vale of Glamorgan Council and local landowners are also involved in the project, which is being funded by the Welsh Government.