Homecoming: Reintroducing Water Voles at Trewithen Estate
The 10th September marked a huge moment for the water vole's conservation journey, as we released 106 water voles into the Fal catchment.
On the brink of recovery
After becoming extinct in Cornwall, with last reported sightings in the 1990s, we are standing on the doorstep of recovery of Britain’s fastest declining mammal. We are thrilled to be part of Kernow Conservation’s mission to see these extraordinary mammals thrive once again. Kernow Conservation first released water voles in South Cornwall in 2022 and have worked tirelessly surveying, monitoring and bolstering this healthy, established population, looking to ecosystems to introduce new populations.
A living landscape
Together, we identified an ideal location for them to establish themselves safely, securely and play an active part in the ecosystem where they belong. Reintroduced to a valley stream amidst organic farmland, we are excited to witness how these mini ecosystem engineers interplay with wetland recovery, woodland creation, and regenerative farming, also at play in the Trewithen Estate landscape. We are excited to see the biodiversity benefits that water voles bring, supporting everything from kestrels to otters, knowing as we do that a thriving ecosystem works hand in hand with farming.
Mink and monitoring
As well as assessing habitat and vegetation at a number of potential release sites at Trewithen, the lead up to the actual release day involved meticulous monitoring for predators. Non-native mink, escaped from fur farms in the 20th century are largely responsible for the purge of water voles. David, Ecologist and Director of Kernow Conservation, installed mink raft within a radius of the release site. Promisingly, sightings of mink in Cornwall have all but vanished in the last decade, and so far, we don’t have reason to worry for these mammals’ survival.
The long-awaited return
The water voles arrived at Trewithen after an hour’s journey from Devon, where they were expertly hand reared by Derek Gow Consultancy, who breed water voles for reintroduction projects across the UK. With Izzie and Katie from Derek Gow Consultancy, we carefully assessed the best release spots, working around the challenge of unusually high water levels. The voles are just 2–3 months old, at this stage weighing about half their adult size of 350-400g, but with a three-week gestation period, we hope to see new arrivals before long.
Thanks to much appreciated hands-on help from Kernow Conservation’s fantastic business members, 26 release cages were assembled and filled with straw, ready for family groups to be gently transferred from their travel cages. It was then all hands on deck to carry each cage, positioning these along the stream at 20–30 metre intervals — reflecting the natural spacing of water vole territories. Each release cage was covered with vegetation for shelter and over the next three days, we returned daily to feed the voles whilst they acclimatised to their new surroundings.
Homecoming
When the time came, the cage doors were swapped for wooden planks with small openings, giving the voles the chance to venture out in their own time. By the following day, all had left to explore their new watery homes.
Nine of the strongest voles were given a “hard release,” straight into the streams below Eagle Ponds, in Trewithen Gardens. Upstream of where the voles released from cages have started out, these water voles’ presence will quickly be noticeable in the gardens, and across a much wider radius, it is hoped. A second release of up to 100 voles next year will help to bolster the population, if necessary.
Trewithen Gardens: Keep an eye out
These charming creatures create burrows in the banks of streams and ponds, with entrances often just above the waterline. If you’re quiet and patient, you might even hear the tell-tale “plop” as a vole slips into the water, nostalgic of a time when water voles were a regular sight in the British countryside. Water voles eat over 200 different plant species, another important role they play in shaping healthy wetlands, so signs of their grazing is a key thing we will be monitoring.
This milestone step has only been possible thanks to the tireless work of Kernow Conservation, and their supporters. Thank you particularly to David Carrier and Nell Sanders Crowden, and to Zac Lazarou and Oliver Cummins for capturing wonderful photography from the release.
From the careful breeding of voles in Devon at Derek Gow Consultancy, to the ongoing mink monitoring ahead, today carries a real sense of optimism for what can be achieved when we work together for nature. We’re all excited for a future where water voles are once again a familiar part of our living, breathing countryside.
c. Photo credits to Zac Lazarou and Oliver Cummins.