Oxfordshire's waterways are overflowing with wildlife - including Britain's most endangered mammal, a new survey has revealed.

Ecologists welcomed the news that the endangered water vole appears to be alive and well in the county's rivers and canals.

But the survey, compiled by British Waterways, also showed "alarming" levels of the non-native mink - the water vole's main predator.

Immortalised as Ratty in Kenneth Grahame's classic The Wind in the Willows, the water vole has small hidden ears, silky mid-brown fur, a blunt nose and a short furry tail.

They make a distinctive 'plop' sound as they enter the water, feed on vegetation, and are different from rats, which have pointed noses and long, pink, hairless tails.

The nationwide survey recorded more than 6,000 sightings of wildlife by the public along the country's rivers, lakes and canals between June and November.

Most common in Oxfordshire, where the survey covered the Thames and Cherwell as well as the Oxford Canal, were mallards, swans, moorhens and herons.

Experts said there was also an "encouraging" number of kingfishers and an "astonishing" number of otters - which are both key indicators of thriving waterways.

Mark Robinson, national ecology manager for British Waterways, said: "The survey shows that wildlife is alive and well on our waterways.

"Apart from the sightings of water voles it is particularly encouraging to see so many other species flourishing that are associated with the waterways.

"Although there was a good number of water voles spotted, I'm very concerned by the sightings of mink.

"In some places the two appear to be living side-by-side but we know that mink pose a real threat to the endangered water vole."

Scientists from Oxford University, together with experts from the Environment Agency, also unveiled a new water vole conservation handbook this week.

The book calls for urgent legislation to protect water voles and explains how to encourage the endangered mammals.

It also gives examples of how developers and landowners can avoid harming existing the water vole population, which is threatened by habitat loss as well as non-native predators such as mink.

National conservation manager Alastair Driver said: "Since 1990, the water vole population in Britain has been decimated, with 95 per cent of their numbers wiped out.

"Without direct action the wild water vole population will decline beyond the point of no return over much of its range within 10 years."