Protecting Yorkshire's water voles

Water voles once thrived throughout the country and could be found on nearly every waterway in Britain. But within less than 50 years populations have plummeted by a shocking 90% - becoming one of the UK’s fastest declining species.

A water vole emerging from a hole. Photograph by Tom Marshall. — (C) Tom Marshall

Yorkshire's water voles

The water vole is one of our most iconic and best loved British mammals. Bigger than most other vole species, the water vole has chestnut-brown fur, a blunt, rounded nose, small ears, and a furry tail, and is famously represented by 'Ratty' in Kenneth Grahame's classic children's tale The Wind in the Willows.

Living along rivers, streams and ditches, as well as other small bodies of water, the best signs of water voles are burrows in the riverbank, often with a nibbled 'lawn' of grass around the entrance.

A water vole sat on a log in a secluded wild water body. — (C) Neil Aldridge

Population status

Sadly the once common and widespread status of water voles is threatened, having suffered a 90% drop in population since the 1970s with many of Yorkshire's wetlands missing this enigmatic semi-aquatic rodent.

In East Yorkshire, however, the picture is a little more rosy, with water vole populations still hanging on and in some areas thriving colonies are still present.

Yorkshire Wildlife Trust have been working to protect water voles across the eastern part of the county for a number of years, carrying out surveys to find out if water voles are present on site and focusing on habitat maintenance and restoration to help support these friendly wetland inhabitants.

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Searching for Ratty

In order to help our native water vole populations, we must first carry out surveys to find out if they are still present on a site. Despite them being active during the day they are still shy and can be elusive, so relying on sightings is not a reliable way of surveying.

Looking for tell-tale field signs becomes the standard way of telling us if they are present or not; water voles leave discrete piles of droppings along the water’s edge, revisiting the same place over and over, creating a ‘latrine site’. However, finding these nestled away in long overgrown vegetation can still be tricky, so we have devised a cunning alternative way of getting good confirmation on the presence of water voles.

A water vole survey raft with latrine. Photograph by Jon Traill — A water vole survey raft with latrine - (C) Jon Traill

The solution has been relatively simple. We create and construct floating rafts made from recycled plastic and tether them to the bankside, floating on the water amongst the reeds and tall grasses. On a re-visit to the site around 10 days later, it is hoped that our water voles have visited the raft and left their droppings on top, using our raft as a latrine site. This is a great territory marker to tell other nearby water voles that this area is already occupied, and also a great way to alert us of their presence.

By spreading these rafts out at regular intervals, we can survey large areas quite efficiently and get fairly accurate up-to-date info on how much area of wetland is occupied. The more rafts with water vole droppings on them, the more water voles we have. Water vole surveying has also proved a popular activity with our volunteers, who have helped to construct the rafts, set them out on a site and check them for signs of activity.

Home sweet home

One of the critical areas of work needed to support our water vole populations is in maintaining and re-connecting wetland habitats across the landscape. It is this linked up network of ditches, ponds and wet grassland alongside the streams and rivers that provide refuge and enable populations to expand and spread out across the countryside.

A mosaic of different wetland habitats offers a refuge for local water vole populations to retreat to when bad weather events such as drought or flood strike, or when there is an increased number of predators in the area. This provides an opportunity for those water voles that remain to breed again and build their numbers back up.

A clear, glassy stream at Skerne Wetlands. — Skerne Wetlands - (C) Peter Batchelor

Our Skerne Wetlands nature reserve at the headwaters of the river Hull near the market town of Driffield has provided a focus for our efforts over recent years.

This site was only acquired around 10 years ago, a former working commercial fish farm, and is now a maze of wetland habitats from reedbed and wet grassland, through to ponds and inter-connecting ditches.

Maintaining and re-connecting our wetland habitat has benefits to other species as well as water voles, from dragonflies and frogs, to kingfisher and minnows.

Yorkshire Wildlife Trust cares for 25 wetland sites across the county but they are the Trust’s most challenging reserves where water levels can be adjusted and specialist equipment and support is needed.