The Water vole (Arvicola amphibious) is a semi-aquatic mammal which lives in the banks of rivers and wetlands, or in small nests in fens and reedbeds. These amiable creatures are sometimes called 'Water rats' (like Ratty in Wind in the Willows). Although they are in the same family as rats (rodents), they are not rats but voles.
The water vole has experienced one of the fastest declines of any native mammal in the 20th century. Populations in Sussex are critically low and it is estimated that we have lost over 90% in the last 30 years. The only remaining large populations of water voles in Sussex are on Chichester Coastal Plain (West Sussex) and on Pett and Rye Levels (East Sussex). There is a re-introduced population of water voles on the River Arun which has bred with remnant Arun valley populations. There may be isolated communities of water voles elsewhere in Sussex but these are small and often genetically unviable populations.
Water voles are a flagship species. We know that if we work to protect the habitats that water voles rely on, we will also be helping a wealth of other wetland species to survive. For more information download our leaflet on How to manage land for water voles and on Water vole facts.
Where do water voles live
Water voles live on rivers, canals, ditches, streams, ponds - and almost any kind of wetland. They prefer slow flowing water with earth banks, which are not regularly flooded, or areas of lush fen and reedbed where they can make aerial nests to safeguard them from flooding and predators. They need luxuriant wetland vegetation (grasses, reeds, flowering plants and sedges) to eat and in which to shelter.
The National Water vole Steering Group suggests that Water voles need a minimum of 6 km of watercourse to ensure the long term viability of a population. On the ground this would equate to a network of inter-linked ponds, pools, wetland habitats and watercourses on a site which would need to be between 100 and 600 ha in size. There are very limited areas of wetland in Sussex which can accommodate a sufficiently large wetland habitat network to support one of these core water vole populations.
Click here for more information on the Wildlife Trusts National Water vole database and mapping project
What water voles eat
Water voles are vegetarian (herbivores) and eat over 200 different species of plant. Their favourite nibbles are wetland plants such as rushes, sedges and horsetail. In the winter they sometimes eat the bark of willow and hawthorn trees. In spring they sometimes eat flowers from bramble and hawthorn. Very occasionally they eat snails and other invertebrates.
Spotting water voles
It is fairly easy to spot water voles if you know what to look for. Here are a few tips :-
- Water voles leave neat piles of chopped vegetation (approx. 4 - 10 cm long with 45 ° teeth-marks at ends) at feeding stations around their territories.
- They leave 'tic tac' sized and shaped piles of droppings around their territories
- They often live in burrow systems. Burrows are normally 4-8 cm across and wider than they are high. Burrows can be found up to 3 m from the water's edge with numerous entrances including some below water. Burrows entrances are usually 'tidy' unlike rat burrows which often have piles of soil outside.
- They can also live in aerial nests which are the size of a small football
- Water voles make a distinctive 'plopping' noise as they jump into the water but remember that frogs and other animals can make a similar sound, as can rocks and branches falling into the water.
For more information and to help you find these rare wetland mammals, download our free Water vole Spotters Pack.
Current threats to water voles
The destruction and fragmentation of wetland habitats has isolated populations of water vole so that they are extremely vulnerable to chance extinction events:-
- Predators such as mink, rats or cats can predate whole colonies of water vole. Mink are one of the only predators that can follow water voles into their burrows.
- Prolonged periods of flooding make water voles vulnerable to predators and flush them from burrows and feeding places.
- Prolonged periods of drought threaten the wetlands and plants that water voles need to survive.
- Accidental deaths through poisoning meant for rats can also be a problem. For more information see our leaflet on How to carry out Rat Control without harming Water Voles.
- Development, drainage and general urbanisation of the natural environment.
New research on water voles
Brighton University have been working with Sussex Wildlife Trust and others on DNA and habitat analyses to establish new national protocols for water vole conservation. So far the research has led to a range of recommendations including :
- Improve habitat networks and connectivity around key water vole populations. It would help if landowners could be supported to improve habitat management for water voles.
- Create suitable habitat on edges of floodplains to provide refuge habitat during floods.
- Increase the occurrence of bank side trees / hedges / reeds / scrub patches along linear watercourse to provide seasonal food and refuge habitat.
- Female water voles appear not to like to pass locations where there are severe changes in habitat. Graded edges to vegetation along watercourses are much better. Sensitive, graded cuts on bankside vegetation should encourage female dispersal.
- Create non linear wetlands everywhere (vertical habitats such as reedbeds, fens, etc).
- Increase survey efforts in non linear sites which are particularly important in winter.
- introduce tighter control on water vole re-introductions to ensure that regionally distinct genetic adaptations to local conditions are preserved, and that no genetic vulnerabilities (i.e. to disease) are introduced.
- Approach Natural England to see if the Arun valley population can be classed as a national stronghold, for which it definitely qualifies.
NOTE: Non linear habitats are 'horizontal' habitats such as reed beds, fens and rush pasture
Click here for more information on Brighton University research.
Current Conservation Status
In April 2008, water voles became fully protected by law under the Wildlife and Countyside Act (1981) Section 9. The increased legal protection added prohibitions against intentional or reckless killing, taking or injury, possession and sale of water voles, making it an offence to intentionally or recklessly damage, destroy or obstruct any structure or place which water voles use for shelter and protection, or to disturb a water vole whilst using such a place. Water voles are a UK Priority Species.
Guidance on water voles
If you are carrying out any work on your land which may affect water voles then you need to show that you have looked for them, and that you have a licence to carry out any work which could disturb them. For more information on applying for licences for work to study or disturb water voles, click here.
The licence type will depend on the scale of work involved, the likely disturbance to water voles, and the level of skill needed to secure the welfare of water voles. In some cases, an experienced local advisor can help you to obtain a ‘licence exemption’ which enables you to carry out sensitive maintenance works at appropriate times of year. If you believe that you will be damaging any water vole habitat, it is recommended that you offer to create a compensatory area of habitat of similar value in its stead. New Guidance on water vole mitigation can be found here (2016).
A Water vole Mitigation Handbook is also available to purchase from the Mammal Society.
See also our leaflet on Mink control for water voles.