Hope for Water Voles as Species Spotted in River Thame Catchment

Britain’s fastest-declining mammal, the water vole, has been confirmed in the River Thame catchment for the first time in nearly 20 years, conservationists have said.

Volunteers from the River Thame Conservation Trust (RTCT) captured video evidence of water voles at two separate locations — the River Thame near Chearsley in Buckinghamshire and the Chalgrove Brook in Stadhampton, Oxfordshire.

The sightings mark the first confirmed presence of the species in the catchment since the early 2000s.

Wildlife Cameras Capture Rare Footage

The footage was recorded using motion-sensor wildlife cameras deployed across the catchment as part of RTCT’s long-running monitoring programme. The project aims to detect water voles and other key indicator species that reflect the health of river ecosystems.

RTCT said the discovery was “sparking hope for the species’ recovery in the catchment”.

The first sighting came from what the trust described as a “dramatic” video clip at the Chearsley site. The footage shows a heron catching and eating two water voles on the riverbank.

“While the footage was not nice to watch, it was also an exciting discovery, evidence of previously undetected water voles in the Thame catchment,” RTCT said.

RTCT said the presence of both predator and prey suggests the river is once again capable of supporting a healthy, functioning food web.

At a second site on the Chalgrove Brook, a volunteer captured footage of a water vole swimming away from a mink monitoring raft. The recording confirmed that at least one animal in the brook was alive and active.

Paul Jeffery, RTCT volunteer and Oxon Mammal Group treasurer, said regular “visitors” included a brown rat, wood mice and two otters.

“But one evening, a thousand clips later, I stopped – ‘what was that?’ The face was more blunt than a rat, the ears and eyes not quite right.

“Confirmed the next day, it was indeed a water vole, moving upstream at 01:00.”

Mr Jeffery said that brought “real hope that water voles are still clinging on and may one day repopulate the whole river system with our continued help”.

Species Has Declined by More Than 90%

Water vole numbers in the UK have fallen by more than 90% since the 1990s. Once common along rivers, streams and wetlands, the species has disappeared from 94% of its former range.

RTCT’s Hilary Phillips said the recent findings were “a fantastic affirmation of all the hard work by volunteers and landowners that our combined efforts are making a difference”.

In the River Thame catchment, the last confirmed records dated back to the early 2000s, when populations were already in sharp decline.

A reintroduction programme was carried out near Cuddesdon and Chiselhampton in 2006 in an effort to boost water vole numbers. RTCT said it is not yet known whether the recently recorded animals are descendants of those reintroduced voles or remnants of surviving native populations.

Public Urged to Report Sightings

RTCT is encouraging members of the public to report any sightings of water voles or signs of American mink to local conservation groups or via national invasive species reporting platforms such as INNS Mapper.

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