Wildlife experts are helping the water vole come back from near-extinction

Ratty liked his lot by the river. "It's my world and I don't want any other. What it hasn't got isn't worth having and what it doesn't know is not worth knowing. Lord! the times we've had together! Whether in winter or summer, spring or autumn, it's always got its fun and excitements."

Sadly the true story for Ratty, the engaging water vole so evocatively portrayed in The Wind in the Willows by Kenneth Grahame, is not one of riparian rhapsody, but rather a sorry tale of tumultuous population decline that has seen numbers in the UK plummet by around 95 per cent over the last few decades.

While habitat degradation has been an important factor in many areas, the principal cause for this dramatic fall is predation by the American mink - an alien species that thrives on our riverbanks and which finds the slow-moving and plump water vole an easy target. When danger threatens, a water vole dives underwater or seeks refuge in its burrow, but the mink is an accomplished swimmer and able to pursue its quarry with great ability. Female mink are even slim enough to pursue the hapless voles down their burrows.

Unfortunately, mink are common along many of the waterways of Scotland.

They originate from North America and are the descendants of animals that escaped or were released from fur farms in Britain in the last century. They have now become firmly established in the wild and their impact on the water vole has been catastrophic.

However, all is not lost and a number of conservation initiatives are underway in Scotland to boost water vole numbers. These include mink trapping and habitat restoration schemes. But one of the most imaginative is taking place on Forestry Commission ground in Loch Ard Forest near Aberfoyle, where captive bred animals are being released back into the wild to replenish former haunts. The results, according to Katy Freeman of Forestry Commission Scotland (FCS), have been truly astonishing.

"Although we were confident the release scheme would work, we have been amazed at just how successful it has been and how quickly the voles have spread from their release sites," she says.

The scheme is led by FCS, and partnered by SNH, the Royal Zoological Society of Scotland, Derek Gow Consultancy, the Kilgarth Development Company, and Loch Lomond & The Trossachs National Park Authority.

The release programme began in 2008 and will continue until 2011, with just under 1,000 animals introduced into the wild. The voles originate from animals that were captured from a construction site near Glasgow, which was near enough to their final Loch Ard Forest release area to ensure a suitable genetic profile. These voles then formed the nucleus of a captive breeding programme.

When the time for release comes, family units of voles are placed in individual pens along the banks of the headwater feeder burns of the Duchray Water, as well as some ponds. Once acclimatised, exit holes are inserted in the pens and the voles quickly find their way out to establish their own territories along the sedge-fringed burns.

One key to success has been the creation of a diverse network of suitable habitats. Areas along burns where trees have been harvested have been kept open and managed to ensure a diversity of flora. New ponds have also been created. Such work has benefited both the voles and a vast array of other wildlife.

Equally important has been the continual monitoring of the mink population and trapping them when their presence is detected. This year has been the first since monitoring began that none have been recorded, great news for the newly flourishing population of water voles. But what are the benefits of returning the water vole to its former haunts?

Katy Freeman says: "Their presence, combined with our programme of creating a rich network of restored wetlands and other habitats in the forest, enhances biodiversity and is beneficial to a large number of species.

"The water voles will also be a great draw for visitors to the area."

• This article was first published in The Scotsman on September 25, 2010