Water Vole

The Water Vole Arvicola amphibius is a small, semiaquatic mammal which is found throughout most of Europe, Russia, West Asia and Kazakhstan. They are much bigger than the other UK voles, and are distinguished from Brown Rats by their slightly smaller size, chestnut-brown fur, rounded nose, fluffy tail and small, rounded ears that don't protrude from the fur. Their brownish colouring helps them to blend in with their environment.

In the UK, Water Voles live in burrows that are generally excavated along the banks of slow moving and calm rivers, streams and ditches. Their burrows have many floor levels within, in order to prevent flooding, as well as nesting chambers and a food store for the winter months. If no suitable banks are available, then they can also live above ground in reed beds where they will weave ball-shaped nests. Water Voles generally prefer lush riparian vegetation as it provides them with cover when they are on the river banks.

Water Voles are herbivorous, mainly eating grass and other riverside vegetation. They often sit in the same spots too, so little piles of nibbled grass and stems can build up on the river's edges. Due to the way Water Voles eat, the nibbled grasses and stems always show a distinctive 45° angled-cut at the ends.

Rubbish photo of a very cool species!
A typical Water Vole is approximately 20cm long, plus a tail of around 11cm, although their weights can vary a lot, from 80-180g. Apparently, the minimum weight needed to survive each winter is 112g for females and 115g for males, and on average, Water Voles only live for 1.5 years.

Water Voles are the UK's fastest declining mammal, suffering catastrophic declines during the 20th century. During the 1940s and 1950s, agricultural intensification caused widespread loss and degradation of habitat, but the major cause of the Water Vole's decline was the release of hundreds of American Mink from fur farms in the 1980s and 1990s. The usual defence mechanisms of Water Voles include diving under water and kicking up a screen of dirt or running into their burrows, however these techniques are insufficient to escape mink. Between 1989 and 1998, the Water Vole population fell by almost 90%, and currently stands at around 875,000.

Due to their extreme declines over the last few decades, Water Voles are protected under section 9 of the Wildlife & Countryside Act 1981, and are also classed as a UK Biodiversity Action Plan (BAP) species. Numerous re-introduction projects have been undertaken around the UK, with most proving successful and Water Voles have now returned to every county in England. We are lucky to have Water Vole living on the UEA campus, along the River Yare, and seeing one brightens up every walk!

Here is a great little video from the Wildlife Trust on the characteristics and ecology of Water Voles:

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