The water vole was once a familiar sight in the countryside, but has been the subject of the fastest rate of decline of any British mammal. Studies in the 90's showed that water voles are now absent in up to 94% of sites previously found in.
So what is responsible for their rapid decline? As with many species, it is a combination of threats... pollution of the waterways in the past have not helped, fragmentation or even complete loss of vital waterside habitats has been a bigger problem but perhaps the biggest threat of all has been the introduction of the American mink. This predator is efficient in preying on mink both underwater and on land, and where as a water vole can escape from many predators by taking to their under ground den system... a mink can often easily squeeze into these tunnels and snatch the voles from their safe haven.
Conservation of this charismatic mammal is undertaken with careful habitat management, controlling of potential predators and even direct re-introductions of the voles themselves into suitable locations. There are a few organisations out there that do great work with water vole conservation, such as Derek Gow Consultancy, but we are focusing our attentions more locally for now.
Great news on our water vole project. Earlier this year we released some new voles out on to our nature reserve, and shortly afterwards we spotted many signs to show that they were still there and present... although didn't see a vole itself.
Well, only a month a go a member to the Centre excitedly told me they had spotted a water vole down on the reserve. Going down to have a look, and not only did we see an adult vole, but also a youngster. This just shows that not only are they surviving down there, but that they are also breeding. Therefore they must be quite happy in their new "wild" home.
At the end of the summer, we also set up our breeding voles ready for next year. I wasn't expecting any youngster to be bred by them before the year was out, but to our surprise we have had a few litters from these voles too. Therefore, at the weekend, we put a further 25 water voles out into the soft release pens around the reserve to acquaint themselves to their new surrounding before we let them go in the new year.
The nature reserve is a tributary of the Eden Brook River, so as time progresses it may be a possibility, with co-operation from neighboring land owners and Natural England, that we could progress this project further to allow the voles to spread upstream and possibly even back on to this Kent river. If this was to happen, we believe it may be the first time water voles were re-introduced on to the Eden Brook.
With the initial releases on to our reserve, the main "potential" problem we can foresee is from that of predators in both the mink and herons.
We have a large colony of herons that live on the reserve, and in other areas they have been known to prey on water voles. I think we have to expect to lose one or two voles to this threat, but we hope to reduce the impact by managing the habitat to give the voles dense cover in key areas of the wetland area and by supplementing the herons diet by putting out any of the waste fish our otters do not eat.
In terms of the American mink, we are working closely we Surrey Wildlife Trust (SWT) and have put out three mink rafts by their design in the immediate area. So far there have been no signs, but if a mink were to be spotted, then it would be controlled for the benefit of the water vole and wading bird population on the reserve.
The SWT are to help with the monitoring of the water vole population on our nature reserve so that we can hopefully show that what we are doing is a success, and resulting in a new population of voles. I will keep you informed through the new year as this surveying is underway.