Water voles are small riparian mammals and members of the rodent family. As their name suggests, they typically inhabit the banks of watercourses and their dense fur, small ears and furry tail make them specially equipped to do so. Water voles live in colonies as large as 150 individuals, they form a network of burrows on the banks of watercourses, which they use for storing food, raising their young and evading predators. Most are a chestnut brown colour however some black water vole populations can be found in Scotland; they are the remnants of a distinct Iberian lineage which migrated here over 10,000 years ago.
Water voles are herbivorous, they can feed on over 800 species of grasses. They must eat around 80% of their body weight every day to compensate for their herbivorous diet and energetic lifestyle.
Catching sight of a water vole in the field can be difficult as they are highly vigilant to predators. Noticeably larger than field voles, water voles are mostly confused with rats which are a similar size and colouration. The main characteristics which distinguish water voles from rats are their rounder face, smaller ears, and hair-covered tail. In the field look out for a muddy rim along riverbeds- evidence of a nearby burrow. If you come across a burrow, expect to see a tennis ball sized hole surrounded by a lawn which they trim at 45° cuts. Their droppings are similar to the typical ‘tic-tac’ shaped mouse droppings though slightly larger in size and can be found in latrines, unlike rats.
Photo credit: Johnathon Ridley - unsplash.
Water voles are hugely influential on the wider ecosystem. Sitting low on the food chain, they are an important prey source for many predators. Their excavations when forming burrows creates fertile soils for wildflower meadows and grasses to grow in, thus boosting biodiversity. Even when water vole colonies have dispersed, their remaining burrows persist for many years and provide suitable refugia for a range of other species including reptiles, amphibians, small mammals, and invertebrates.
Water voles are hardy animals which have persisted through several ice ages. Their populations naturally fluctuate between seasons however, a combination of pressures has seen their populations drop by almost 90% over 10 years. Intensive agriculture and extreme weather as a result of climate change floods and destroys water vole burrows. The invasion of the American Mink, a non-native predator, has also decimated water vole populations. Owing to this, water voles receive legal protection in the UK under Schedule 5 of the Wildlife and Countryside Act 1981. Captive breeding, reintroduction, and translocation programmes are also in place to help recover their historic numbers and consequently the ecosystem benefits they provide.
If you have a development which might interfere with water voles, or their resting places then please get in touch with our Ecology team at email@example.com or call 01381 610313.