I’m sure most of you will have seen a dog digging, it’s forepaws scrapping away like crazy.  Even if you haven’t actually seen it, I am equally sure you can picture a mole tunnelling away underground.  Water voles also make burrows, but these incredible little animals do not dig into the river bank.  No, they chew their way in.  Using their constantly-growing incisors, water voles gnaw away the dirt which is then pushed aside by the front feet.  This is just one quirky fact about water voles that makes them so appealing. 

Another fact is more alarming.  Water voles may be Britain’s fastest declining mammal.  Disappearing quicker than anyone else is not a race anyone wants to win but, sadly, water voles may be out in front.  It is estimated that they are only found in 5% of their historical range.  Having once been found across almost the entire UK, they now only exist in small patches and pockets.  Imagine a Christmas tree covered in lights.  Slowly, start turning off the lights until you have turned off 95% of them.  How does the Christmas tree look now?  Here, at Durham Wildlife Trust, we want to make sure no more lights go out. 

The threats to water voles are the usual suspects: habitat destruction, land use change, pollution and climate change (remember how dry last summer was?  It’s no fun being a water vole without water).  However, the single biggest threat water voles face is a novel one: American mink.  Mink were brought to the UK to be farmed for their fur.  Some escaped from the fur farms but many more were released by animal liberationists.  They have now become established and widespread.  That’s a problem because like their natural relatives, otters, polecats, stoats and weasels, American mink are fearsome predators.  However, they are also able to exploit niches that the others cannot.  Polecats are pretty strictly terrestrial while otters are predominantly aquatic.  American mink have the best of both worlds: excellent swimmers, with insulating fur, they can also move on land.  Otters are too big to enter water vole burrows, but a mink can.  Once inside a burrow, a breeding female and all her pups may be eaten.  Given that, it is easy to see how quickly a population can crash; if there are no adults and no young, what’s left? 

There is good news, however.  Firstly, there was once a huge number of water voles so, even though the decline has been dramatic, the starting point was so high – certainly in the millions – that quite a few water voles remain.  That gives us something to work with.  Secondly, we know how to control mink.  They can be caught in traps on floating rafts.  This design reduces the risk of catching other species (the entrance to the trap is too small to catch an otter).  Finally, so many people are concerned about our native species, and the health of our waterways, that we have a potential army of helpers. 

Since 2020, Durham Wildlife Trust has been running the Naturally Native project, in partnership with Tees Valley and Northumberland Wildlife Trusts.  Funded by the National Lottery Heritage Fund, the project aims to save water voles, across the three major river catchments of the North East, the Tees, Wear and the Tyne.  There are four elements to the project: habitat improvement, mink catching, education and outreach, and field surveys.  The last is particularly important as it will prove the success of the other initiatives.  Surveys are also where we need most people. 

Throughout the spring and summer of 2023, we are hoping to run water vole surveys along as many water courses as possible.  This is essential to give us a clear understanding of where we need to target our efforts into the future.  Who knows, we may find voles in places we didn’t know about. 

A survey is not a complicated undertaking.  Essentially, it is a walk along a water course looking for field signs: latrines, burrows feeding stations and tracks (though good luck with the tracks!).  These can be done at any time and is not a group activity.  Indeed, we are hoping we may end up with a network of volunteers, spread across the region, who would survey the brooks, burns, becks and streams in a 3 – 5 km radius from their homes.  Obviously, access isn’t possible everywhere so we expect people to use footpaths and bridleways.  It will still give us a picture of where water voles are hanging on.  If we know where they are, we can protect them.