WATER VOLE: on the run from savage invader

SHY, secretive, and facing extinction, the water vole is yet another native creature driven to the edge thanks largely to an American immigrant.

Just as the American grey squirrel evicted our own red squirrel from much of its old stamping grounds, the mink is now driving out the water vole.

However, unlike the grey squirrel, the ferocious mink actually preys on its victim and has developed quite a taste for water voles (traditionally, also known as 'water rats').

Countless numbers of these small, peaceful rodents - made famous by 'Ratty' in The Wind in the Willows - have been killed and devoured by mink after the intruders were first introduced here from North American fur farms in the 1920s.

Feeding solely on vegetation, water voles are easily distinguished from real rats thanks to their blunter faces and rounder, shorter bodies. Unmolested, water voles live in a system of burrows dug into the bank beside rivers and lakes, the male often spending his entire life within a 150 metre territory.

The female water vole needs even less territory but is more likely to up sticks and move.

Even without the explosion of the mink population, water voles already faced a host of deadly predators, from herons and owls to pike and stoats. It's been a long time since I heard the distinctive 'plop' of a water vole fleeing into water at my approach.

Years ago, at a local lake I frequented, not only would you hear the noise but, if you stood still long enough, you might even catch a glimpse of the water vole that made it.

This is far less likely now.

Water voles have disappeared from almost 90 per cent of the UK sites they once occupied.

Without efforts to protect them, it is estimated that these timid, harmless creatures could soon be extinct here.

Unlike true rats, which can also swim, water voles thrive only in quiet stretches of clean water - which brings us to the second major cause of their decline: loss of habitat.

Fortunately, Wildlife Trusts around the country have made it a priority to try to save 'Ratty' from his terminal decline and protect his remaining territories.

As well as controlling mink predation, their efforts will involve managing the kind of habitats that water voles require.

Simon Lyster, Director General of The Wildlife Trusts, explained recently:"The peaceful riverbank that was the scene of Ratty's adventures has changed out of all recognition in many areas over the last 50 years. "Riverside building, changes in farming practices and changes to rivers themselves have all contributed to the destruction of the water vole's haunts.

"As a result, water voles are hanging on in the few refuges where conditions are suitable. It is our duty to 'Ratty' to involve everyone in water vole conservation and we are determined to do all we can."

For poor Ratty's sake, I hope it's enough.