Water vole

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A water vole sitting in a stream. water_vole_7.jpg
The brown blob of a water vole.
Perhaps the most exciting organism I have seen at UEA whilst being on campus is the water vole. We were walking along the river when a small brown mousy looking creature appeared. I tried to take a picture, as at the time we weren't sure what it could be, but the picture (as seen below) didn't aid the investigation too much. After doing a few google searches a water vole seemed to be the best fit for the mystical creature we had seen. Their scientific name is Arvicola amphibius and they are fairly small mammals. They weigh up to 300 g and are 14-22 cm in length. They are protected under The Wildlife and Countryside Act of 1981 but face serious threat from the loss of their habitats and from the invasive species the American mink. They can be recognised by their blunt noses, small ears and furry tails. They are usually found along waterways such as rivers and in ditches around ponds. They are creatures of habit and like to sit and eat in the same place so one area around the waterway may have an area of nibbles grass.

Their breeding season begins in March and continues right the way through until October. Annually, females produce 2-5 litters of around 2-8 pups. When they are born the pups are hairless and blind so are very reliant of their mothers during the first period of their lives. After 28 days the young leave their mother and after their first winter they reach sexually maturity. If in the first 28 days the mother does not feed to pups enough for them to weigh over 170 g it is very unlikely that they will survive their first winter.

Water voles biggest predators the American mink MinkAmerican_photo_LCampbell.jpg
There is a long list of threats that water voles face and the most deadly could be habitat loss and degradation. As the human population has grown and urbanisation has had to spread onto floodplains there has been a direct loss of habitat for the water voles and also vegetation and therefore their food source. The inappropriate management of channels and waterside vegetation has also lead to the loss of water voles. Pollution is also a threat to the species as pesticide runoff into rivers has lead to a direct decline in water vole population numbers. The biggest predator to water voles is the American mink. This is an invasive species that is non-native to the UK and was introduced in the 1920s to fur farms in Britain. However, the mink started escaping and were briefing in the wild by the 1950s. As a usual defence mechanism water voles dive into water and run into their burrows but this is useless against the mink as females can fit into the burrows of water voles and wipe out a whole colony at a time. There are methods in place to try to control the mink and take pressure off water vole populations.

I really hope this species doesn't decline to a point of not being able to recover again as they are truly beautiful creatures and a joy to see whilst on a walk (even if you are not too sure what they are).

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