In our series of blogs for 2024, we’re going back to basics. This is a guide for budding ecologists who are keen to get started in the industry, or anyone interested in learning a little more about professional ecology practices in the UK.
For October, we're looking at water voles.
About Water Voles
European water voles (Arvicola amphibius), often mistaken for brown rats, are distinguished by their smaller, rounded ears, round faces and blunt noses. These rodents make their homes in burrows along the banks of slow-moving streams, rivers, lakes, canals, and ponds across the UK, preferring lush vegetation which offer shelter, food, and the roots support the structure of burrows.
They breed from March to October, so this is when water voles are particularly active. Unlike many other mammals, water voles do not hibernate through the colder months, remaining active and diurnal throughout winter.
Their diet shifts with the seasons: in spring and summer, they feed on vegetation and fruits, while in autumn and winter, they turn to roots and bulbs. Female voles are territorial, marking their areas with latrines near the entrances to their burrows and along their boundaries, ensuring their space remains defended.
Water Vole Conservation
Water voles are a protected species under the Wildlife & Countryside Act of 1981 and are listed as a priority species in the UK Biodiversity Action Plan due to their dramatic decline. Once abundant across the UK, water voles have faced a staggering 94% decline in their habitats over the past few decades.
This alarming drop is attributed to several threats, the most significant being predation by the invasive American mink, causing local extinction. Habitat loss has also taken a toll, particularly as floodplains and waterways are developed for agriculture and urban expansion.
Additionally, agricultural runoff and water pollution severely degrade the voles' habitat, impacting the availability of clean, slow-moving water they depend on. Poor waterway management, including the destruction of riverbanks and vegetation crucial for their survival, further exacerbates their decline.
Survey Methods
Detecting the presence of water voles is primarily done through observation of field signs when voles are most active in Spring and Summer. Specialised water vole traps are occasionally used for more in-depth population research.
- One of the most common indicators of water vole activity is their droppings, which are smaller than those of rats and are odourless. Conservationists often conduct latrine surveys, as water voles create latrines near their burrow entrances or along territorial boundaries where they regularly deposit droppings.
- A newer survey method, which you can read about on the PTES website here, exploits the water voles' behaviour by providing them with rafts as a feeding platform and floating latrine.
- Another key sign is their feeding habits; water voles tend to gnaw vegetation at a characteristic 45-degree angle, leaving neat piles of chewed stems in favoured feeding areas.
- Footprints left in soft mud along the water’s edge can also reveal their presence, with their distinctive, small tracks offering clues.
- Their burrows, often found in riverbanks, frequently have entrances submerged underwater, offering the voles an escape from predators. A clear sign of an active burrow is a "lawn" of closely grazed grass around the entrance, which they maintain to monitor their surroundings and forage nearby.
These field signs, combined, provide a reliable method for identifying the presence of water voles in the wild.
Mitigation Methods
Habitat restoration and enhancement is the primary strategy in ensuring the survival and of water vole populations. Part of this is ensuring the waterways are well-maintained, clean, healthy and less prone to flooding.
Secondly, controlling mink populations is a critical measure. As predation by American mink is one of the biggest threats to water voles, controlling mink through targeted trapping programs helps reduce the pressure on water vole populations and allows them to repopulate restored habitats.
Using traps specifically designed for water voles to reduce stress are used for research and relocation purposes. In cases of habitat loss or danger, water voles may be translocated to safer, restored receptor sites where they can thrive.
Installing fencing to exclude or protect key vole habitats can help safeguard against predators like mink. The fencing needs to include an underlap, a portion of the fence buried below the ground, to prevent predators or voles from digging underneath.
There are now many water vole reintroduction projects around the country, to release individuals into safe and suitable habitats where they have previously been extinct. For example,115 water voles were released in September 2024 as part of Nottinghamshire Wildlife Trust's water vole recovery project , which you can read more about here.
