Cornwall Mammal Group
Recognition:
The water vole is the largest of the British voles. It has dark glossy chestnut-brown fur, a blunt nose, short, furry, rounded ears, small black beady eyes and a long hair covered tail. Close up, its bright orange incisor teeth can be seen. The head and body are 120 to 220 mm long and the tail 95 to 40 mm; they weigh up to 300 g. Males are slightly bigger than females. When disturbed, water voles enter the water with a soft ‘plop’ and they may be seen swimming with their blunt noses held clear of the water at the tip a
v-shaped bow wave. When swimming underwater they may kickup clouds of mud to screen themselves from approaching predators. Water voles are often confused with the similarly sized common rat, as both species are found on, or near, water.
However, the common rat is generally larger with more prominent eyes, large hairless ears, and a pointed muzzle. The rat’s tail is also longer and hairless.
Did you know?:
Water voles are often mistaken for common rats, and are actually known locally as water rats. Ratty in Kenneth Grahame’s The Wind in the Willows is actually a water vole.
The last sightings of water voles were in the late 1990s from near Par, Godolphin and Bude. Although reports of water voles are received each year by ERCCIS, none have yet been confirmed. In June 2013 the first phase of the release of 100 captive-bred water voles was commenced on the Bude Marshes.
© David Chapman
In Britain water voles live by waterways, preferring slow-flowing rivers, streams, ditches and even ponds. Cornwall’s rather fast-flowing and spate-prone upland rivers do not provide ideal habitat, but lower reaches and marshland are all suitable. Water voles use their large incisor teeth to burrow into the bank to create a tunnel system. The tunnels have multiple entrances, some below water level, as well as nests and food caches. Nearby water provides a convenient escape route. The female water vole occupies a territory of about 70 metres of river bank. She breeds after her first winter, from about March to September, having up to five litters per year. The litter consists of 2 to 9 blind and naked young which are born underground, being fully weaned at about 4 weeks. The male has a much larger territory, covering several female territories. Both male and female rarely live beyond 2 years and the average life expectancy is less than 6 months.
Water voles are opportunist herbivores, and have been recorded consuming a varied diet which may include over 200 plant species. Grasses, rushes and sedge are eaten in the spring and summer; roots, bark and fruit in the autumn and winter. In central Europe water voles often live in grassland burrows far from rivers and they are considered a pest because of damage they cause to root crops and banks.
Foxes, otters, stoats, weasels, domestic cats, rats, owls, herons and pike, as well as American mink, will all eat water voles. Despite this list of predators water voles are able to recover rapidly from limited local population crashes caused by flooding or cold winters providing that habitat continuity permits the animals to move between suitable areas, and that American mink populations are effectively controlled locally.
Survey Methods:
Burrow surveys. Feeding signs and latrines. Prints - mink rafts, developed by the Game and Wildlife Conservancy Trust to survey and trap American mink, can also be used to monitor water voles. The plywood and polystyrene rafts incorporate a bed of wet clay within a tunnel housing. Water voles and other semi-aquatic mammals entering the tunnel leave distinctive prints which remain identifiable for several weeks.
The water vole makes burrows (4 to 8 cm in diameter) on bank sides close to the water’s edge, often with entrances above and below the water. Grass surrounding the entrance may be close-cropped. The characteristic tracks can be found in mud at the waters edge, identified by star-shaped pattern of the four-toed forefeet. The hind foot has five toes, with the first and fifth digits leaving prints almost at right angles .In the summer water voles mark their territories with latrines of cylindrical khaki/light green droppings about 1 cm in length, often associated with food caches of neatly cut lengths of vegetation. Water voles are creatures of habit and vole runs can often be seen in the bankside vegetation, or leading to places where they enter or leave the water.
Distribution:
Once widespread across Cornwall, the water vole is now considered extinct in the county although reintroductions are being carried out in the north east of the county. Present throughout the UK, although having declined
dramatically in the last 30 years, the water vole is also found from Western Europe to the tundra of central Siberia.
Records:
2007-2012: 0
2002-2007: 0
Pre-2001: 58
Total: 58
Conservation:
The water vole is Britain’s most rapidly declining mammal. The impacts of habitat destruction, agricultural changes, domestic pets, rodenticides, and the depredations of the American mink, are now combined with geographical and genetic isolation of the remaining populations. Recent national surveys estimate 94% of water vole sites have been lost. Maintaining and enhancing habitat, limiting over-grazing, and active control of American mink all contribute to the protection and support of water voles in the UK. Since 2001 more than 20 re-introductions have taken place across the UK, using captive bred animals with varying degrees of success. Water voles are legally protected in Britain under the Wildlife and Countryside Act 1981 (as amended in 1998). The water vole is a priority species in the UK BAP and the Cornwall BAP although there are no active plans to reintroduce the species to the county.
