Water vole numbers have plummeted in recent decades. The decline has been one the steepest of any British mammal (an unenviable position). They’re now absent from 94% of their former sites. Here in Surrey, the last reported sighting of a water vole was six years ago. But have they disappeared from Surrey completely?
A sighting from a decade or two ago indicated that there had been water voles along the stretch of the River Mole that I survey for Riversearch. Yesterday I set out, with Alex from Surrey Wildlife Trust, to see if there were any traces of water voles remaining.
I have to admit that I was skeptical. While my stretch of the River Mole has escaped some of the modifcations that drive water voles away (concrete banks impossible to climb or make burrows in), it’s still not promising water vole habitat. There’s not a huge amount of vegetation in the river, and the Mole isn’t renowned for its water quality. (There’s a sewage works just upstream from my patch, and it starts life at Gatwick airport, which is hardly auspicious).
The survey involved one of us (Alex, since she possessed some very leaky waders) getting into the river, and walking along a stretch looking closely at one bank for any signs of water voles (burrows, pawprints, droppings, feeding lawns). Meanwhile, I followed along the top of the bank, drawing a map of key features.
The 100m stretch we surveyed had steep earth banks, and was lined with trees. The river was mostly fairly shallow at this point (0.5m). Sadly there was no sign of any water voles. And, even worse, there were lots of signs of mink. The rise of mink (an invasive non-native species) has been another key contributing factor to the decline of the water vole, as mink are excellent hunters and small enough to fit in a water vole’s burrow, leaving them no safe place to hide.
Apart from the mink signs we also found some juvenile rat prints, some heron prints and saw a kingfisher.
While it was disappointing result, this sort of evidence is needed to work out how best to help water voles recover in Surrey. So far 40 surveys, like the one I carried out, have been done on sites where old records of water voles exist. There’s about 200 sites in total that Surrey Wildlife Trust want to check, before proceeding to the next stage. As well as actively surveying sites, they’re also asking members of the public to submit any water vole sightings in the county. They have a useful vole ID guide on their website.