Holes in the map, part 4: Water Vole

The fourth part of the series focusing on species missing from the Lake District, Site Manager Lee Schofield looks for water voles.

For aeons, The Lake District and its abundance of lakes, becks, tarns, ditches, bogs and ponds was heaven for water voles, one of the UK’s most endearing small mammals. Made famous by the affable and breezy character of Ratty in The Wind in the Willows, water vole’s relationship with the wet parts of our landscape go deep. When asked by mole whether he lived by the river, Ratty replied “by it and with it and on it and in it”. A river without water voles is like a sky without birds.

Also known as water rats, water voles are easily distinguished from brown rats, which they often live alongside. They are rounder, blunt-nosed, and some might say cuter than rats. Predominantly herbivorous, water voles feed in lush vegetation at the water’s edge. Their habit of sitting in one spot to feed creates little ‘vole-lawns’ which are a classic sign of their presence. During the summer, they make hay, dragging cut lengths of plants down into their burrows to see them through the winter months. Spending so much of their time hidden by thick plant life, or in the water or their burrows means that water voles aren’t often seen. The give away that you might have been near one is a characteristic ‘plop’ into the water, and perhaps a silver stream of bubbles as they swim away.

Ten times the size of the short-tailed field vole, their more numerous cousins, water voles make a hearty meal for a long list of predators. As well as those species we still have, they would have been guzzled by Cumbria’s golden eagles and wildcats while they were still here. Water vole’s appeal as prey has driven the evolution of a brilliant defensive strategy. They dig L-shaped burrows close to slow moving water with one entrance opening near the water’s surface and a second on the land above. If a predator like a fox, owl or a buzzard should approach while the water vole is on land, they nip into their dry entrance to escape. Some predators, like stoats, weasels and snakes, are small enough to fit into the burrow, so the escaping water vole dashes all the way through and out of the lower door into the water. Being strong swimmers, they stand a good chance of outpacing any skinny pursuers. If a heron, pike or otter comes at them from the water, they nip into the waterside hole to get away.

This beautiful balancing act between predator and prey has worked for the water voles since time immemorial, allowing them to persist alongside their many hungry neighbours. Recently though, the arrival of an invader has brought hard times for Ratty.

American mink, sleek black members of the badger, otter and stoat family, were brought to the UK for fur farming in the 1920s. There was minimal regulation of these farms and the sneaky mink dribbled out of them. Over the course of decades, these escapees have established themselves widely across the UK countryside. Mink are generalist predators, eating whatever they can catch. Strong swimmers, they spend most of their lives close to water, breeding under the roots of bankside trees and in other shady places. Larger than stoats, but far smaller than otters, mink are just small enough to fit down a water vole’s burrow, and it is this characteristic that spelled disaster. The carefully balanced strategy the water voles had evolved over aeons was suddenly rendered useless – mink can chase water voles from land or from water, enter their burrows, outswim and outrun them. The water voles stood no chance.  

Largely thanks to mink, water vole numbers have crashed and they’ve vanished from over 90% of their former haunts. In the 60s their numbers across the country were estimated at 8 million, now there are less than 900,000. In Cumbria, where water voles a century ago were everywhere, they are now restricted to just the Pennines. They do well around Alston and are seen from time to time around Melmerby and Renwick. In 2007, Cumbria Wildlife Trust and Eden Rivers Trust successfully reintroduced them to the Warcop area. One of the places that they seem to have gone from altogether is the Lake District, though it’s difficult to be completely sure.

Over the past few years, we’ve had several reliable sounding reports of water voles having been seen in Swindale, part of the land we are looking after in partership with landowner United Utilities. My colleagues and I have searched for them in likely spots but we haven’t found anything conclusive yet. We set up a couple of remote cameras, but other than a photo of a surprised looking otter, they didn’t turn up anything either. What we did find though, were water vole burrows, and lots of them. Their burrows can persist for years after water voles vanish from an area, and they show beyond doubt that they were in Swindale until relatively recently. A local resident told me that a few decades ago, water voles were so common in the area that he used to shoot them for target practice. Perhaps they are still clinging on in a boggy corner somewhere, where the mink haven’t yet found them.

Thanks to increased control of mink and a growing number of reintroductions across the country, the tide is starting to turn for water voles and their numbers are currently on the up. But bringing them back is no easy business and unfortunately there is a degree of killing involved. There’s no point returning water voles to their watery abodes if mink are still in the area, so any reintroduction programme needs to go hand in hand in with effective and sustained mink control. Akin to the killing of non-native grey squirrels to protect the native reds, some people find this a difficult moral decision to wrestle with. Mink have a devastating impact not only on water voles, but also on many species of ground-nesting birds and other wildlife, so while it’s something that not everyone will be comfortable with, in my view the benefits of mink control to our native wildlife outweigh the costs.

In Cumbria, several organisations and individuals are starting to think about larger scale efforts to bring Ratty back to Lakeland. Mink trapping is already happening, thanks to the efforts of a handful of dedicated volunteers, but it needs coordinating and proper funding to ensure that it can be sustained in the longer term. Working together at a landscape scale, with all interested parties is the only way to carry out effective nature conservation, and water voles, being so well-loved seem to be a species that are able to bring people together. Not only are they cute and cuddly, but their value as a prey item to native species means that they are an important missing piece of the Lake District’s ecosystem. Let’s hope they won’t be missing for that much longer – watch this space…