Rescue plan for Ratty

The water vole: Pushed to extinction by the mink

A much greater effort is needed if the water vole, Britain's fastest declining mammal species, is to be saved from extinction, say Oxford University scientists. One of main threats comes from deadly attacks by escaped mink.

The water vole, popularised by the fictional character Ratty in Wind in the Willows, used to be a very common sight along riverbanks but is now disappearing at such a rapid rate that it is likely to become extinct in the next few years.

Riverside management needs to be improved

Professor David MacDonald, Director of Oxford's Wildlife Conservation Research Unit (WildCRU), says the water vole must now be given special attention and his group have outlined measures which may yet bring the little creature back from the brink.

In particular, he says every effort should be made to help the animal evade the clutches of its most serious predator, the American mink, many of which have escaped or been released from fur farms. There are probably now about 10,000 mink in the wild as a result.

"American mink are truly marvellous animals, one can only be in awe of their adaptability," says Professor MacDonald. "However, it is tragic that such an intriguing, and beautiful, species should find itself a pest due to the folly of those who thoughtlessly transported them beyond their native range in North America."

WildCRU has released two reports. One details the numbers of water voles at sites across the UK on such rivers as the Thames, Windrush, Teifi, Itchen, Arun, Bure, the Oxford Canal and on the islands of Sheppey and Wight. Numbers are now just a third of what they used to be. The report also includes an assessment of the different threats the water voles face. As well as the mink, these include:

• changes in land use and the increased intensification of agriculture
• flooding and climatic change
• changes to riverside management and the loss of habitats

The second report gives information on how habitats can be improved for water voles. It comes in the form of a handbook that conservation managers can use to help them improve the quality of water vole habitats.

The recommendations include:

• restoring the streams and ditches off rivers that have disappeared because of dry weather or over-abstraction
• fencing riverbanks to prevent them being trampled on by cattle and other livestock
• increasing the size of riverbanks and allowing more space for vegetation
• trapping and removing specific mink populations

All these measures would increase the amount of food and cover for water voles and allow them to live at much higher densities than is currently possible on so many of the UK's waterways.

"All too many modern riverbanks provide scarcely more than a ribbon of fringing vegetation so narrow that any patrolling mink is certain to find water voles," says Professor McDonald. "It is like a tightrope on which the water vole teeters, but off which it can easily plummet to extinction when dislodged by the mink."

The reports have been published in collaboration with the UK's Environment Agency, English Nature, and the Scottish Environment Protection Agency.

All images from the Wildlife Trusts