UK water voles
Seeing a water vole swimming across a slow-moving stream, or “plopping” into the water, is now unfortunately a rare event.
Water voles have been struggling across the nation; they are classed as Endangered on the UK Red list, and unfortunately still declining.
For those not lucky enough to have spotted one, water voles are the UK's largest vole, around the size of a small guinea pig. Their coat colour varies across the UK, a reddish/brown coat in England, with darker brown/black variations in Scotland. They are a semi aquatic rodent, that feed along riverbanks, ponds and wetlands, and a highly important species within their ecosystem.
There is hope for water vole, as some areas in the UK are seeing water vole populations recover. In London, we are leading a collaborative Water Vole Recovery Programme to help restore this iconic species back across the city.
The London Water Vole Recovery Programme
The London Water Vole Recovery Programme (LWVRP) was created to restore water vole across the capital, an area where they once thrived.
The programme brings partners together from across London to contribute and work towards water vole recovery. The programme was formed in 2023 with the People's Trust for Endangered Species, Greenspace Information for Greater London, London Wildlife Trust, Waterlife Recovery Trust, and was supported by the Mayor of London.
Early milestones of the LWVRP include, bringing together stakeholders from across London in a series of practitioner meetings, determining the baseline remnant water vole distribution, developing the London Water Vole Action Plan, training volunteers to survey for water vole, facilitating the roll-out of an American mink- trapping programme and identifying sites where water vole recovery could be feasible. The full action plan can be viewed here.
How can you help?
Reporting mink sightings
By reporting any mink that you spot while walking, especially near a river, you will be helping the local water voles and other wildlife in the area. Waterlife Recovery Trust will be able to quickly see the sighting report and add/adjust the local trap network to help catch them. Removing American mink from the landscape, although unpleasant, is a hugely important step to allowing water vole and other native species to recover.
Report a water vole sighting
We need your help to continue to help us build up a picture where water vole are in the capital. Where remnant water vole populations exists and in the absence of mink, they may start to recover, expand and recolonise stretches of the river. You can play your part by looking for and reporting water voles if you see them when walking by a river.
Join / register a site to survey water voles
If you want to get more hands on with the project, then we are looking for volunteers to systematically survey stretches of river looking for water voles. Our partners, The People’s Trust for Endangered Species run the annual National Water Vole Monitoring Programme. These surveys help us to understand their distribution, and their population trends. Currently, only a few survey sites exist within Greater London and we are looking to help expand this number.
A water vole (left) and a mink (right)
Where to find water voles
Water voles live along slow-flowing rivers, streams, ponds, lakes, canals and reedbeds, preferably with a water depth over 1 meter. They prefer water bodies with large swathes of diverse vegetation, emerging from both the riverbank and the water itself. As they create burrows inside sheltered, steep banks of 45 degrees or more, they have an affinity for soft, easily penetrable earth.
Some water vole colonies are fossorial, meaning they are grassland based and live in underground burrows. This is common in mainland Europe, where they can be found in high numbers and are even considered pests in some areas. Some fossorial water vole colonies exist in Scotland.
Ecosystem engineers
Water voles are ecosystem engineers as their population dynamics, feeding and burrowing behaviour can influence their environment and effect plant diversity. Feeding on the roots and shoots, water voles can prevent a single plant species from becoming dominant and can help with seed and rhizome dispersal. Their burrowing can also alter the soils moisture levels, biological properties and microbial activities, which in turn regulates the availability of nutrients for plant growth. Studies suggest that with the declines of water voles, plant communities will become less diverse which will result in biodiversity loss.
What do water voles eat?
Water voles are herbivorous, with 227 plants recorded at feeding sites. During pregnancy, the females have been known to supplement their diet with flowers, for their protein rich pollen and sometimes even eat molluscs, snails and small fish.
Water vole lifecycle
Water vole populations boom in the summer, females can have 3-5 litters between March and September, with up to five young per litter. Life expectancy in the wild is just 5 months on average, due to the high predation rates of juveniles, often occurring when they are dispersing. In some colonies, over winter mortality can be very high, up to 70% and most individuals won’t survive more than two winters. Water voles do not hibernate but can spend a long time in their nesting burrows during the colder winter months.
Native water vole predators
In a healthy ecosystem, water voles are an important food source for all kinds of British wildlife, including foxes, otters, stoats, weasels, owls, herons, marsh harriers, and pike. Their high breeding rate and natural predator avoidance mean that water vole populations can survive these naturally high mortality rates.
A heron and a stoat are two predators of a water vole
How to identify water voles in the UK
Water vole droppings
Water vole droppings are “tic-tac” shaped, dark brown to green and completely odourless. They can be distinguished from rat droppings by their shape, as rat droppings have pointed ends compared to water voles which are blunt. They often latrine on objects that protrude from the water like rocks and woody debris.
Water vole feeding signs
Water voles make feeding stations along the banks and leave behind neat piles of chewed vegetation. Stalks and stems that they eat are left behind with 45-degree cuts to their ends.
Stalks and stems that have been chewed by a water vole
Water vole or rat?
Water voles will enter the water when startled, unlike rats which usually dash into vegetation. Water voles have small rounded fluffy ears with blunt brown noses with a short furry tail. Rats in comparison have a much longer tail, pink pointy ears and a nose without fur.
Waters voles are very buoyant and fast swimmers, they make a 'plop' sound when they enter the water and look like a small rugby ball as they float. On the ground, they often sit on their haunches, munching vegetation or grooming.
Water vole burrows lead into the water and have a nibbled lawn around their entrance. In comparison, rat burrows tend to lead away from the water and are clear of vegetation. Rat burrows also have spoil scattered around and are well worn between holes, with a smell of ammonia and droppings scattered along runs, whereas water vole burrows are neater and their droppings will be in piles.
A rat (left) and water vole (right)
American mink and water voles
American mink are a medium-sized member of the weasel family. A non-native predator, that originally escaped or were released from fur farms in the 1920s, American mink are very efficient predators of water voles. For example, female mink can enter water vole burrows with ease and predate a mother and her pups, meaning healthy water vole colonies can quickly go locally extinct when discovered by this predator. Mink also predate on a wide range of native waterfowl, amphibians and birds, such as kingfishers and sand martins.
Over the years, American mink populations increased and they are now widespread throughout the UK. Studies have shown that where large, stable water vole colonies existed, many have since been lost due to mink. These predators can travel 20-40 km within a short period of time, meaning no water vole colonies are safe from the highly effective predator.
The Waterlife Recovery Trust, a charity leading the national mink eradication programme, have shown that in areas where mink have been eradicated, water vole and other native species have recovered in abundance.
Identifying American mink
American mink are most active at dawn or dusk and are usually seen in and around water. They commonly have a dark to light brown coat, with a small white patch under their chin, however pale colour morphs can occur. Mink are commonly mistaken for other members of the weasel family, like ferrets, polecats and pine martins, due to their similarity in appearance and movement. They have five toes which radiate from a crescent-shaped central pad which can be seen in soft mud, while on harder surfaces their tracks might only show four visible toes. Their paw size are around 3cm-4cm wide and leave tracks similar to cat footprints.
Finding London's water voles
Help us find London's water volves
Get involved with London Water Vole conservation
We need your help to identify and record any water vole or mink you come across. Find out more information on the programme, and how you can get involved.