UK’s Fastest Declining Mammal Brought Back to River Ver

Living Magazines Water vole © Russell Savory

Water voles have been reintroduced to the River Ver after a 34-year absence.

On Tuesday 10 August, Herts and Middlesex Wildlife Trust, in partnership with the Ver Valley Society and a number of private landowners, reintroduced the nation’s beloved water vole to a stretch of the River Ver to the west of St Albans. The reintroduction was made possible by funding from the Debs Foundation and Linder Foundation.

Water voles were once abundant in rivers throughout Hertfordshire, but populations have declined by over 90% in the last 50 years due to habitat loss and because they are being killed and eaten by American mink, an invasive, non-native species. Water voles are the fastest declining mammal in the country and face extinction. Increases in the population have only been noted in recent years where habitats have been improved or through carefully planned reintroduction programmes.

Herts and Middlesex Wildlife Trust is aiming to have thriving populations of water voles back in every river in Hertfordshire by 2030. Last week, specialist breeders brought the 150 water voles from Devon to a stretch of the River Ver to be released. Prior to this reintroduction, the last recorded sighting of a water vole on the River Ver was in 1987.

Water Vole Conservation Officer Josh Kalms said: ‘We are thrilled to have reintroduced water voles to the River Ver. Water voles are a key species in wetland ecosystems and their actions are important for maintaining healthy wetland ecosystems – they are mini ecosystem engineers with their burrowing and feeding helping our river banks and wetlands stay in good condition.’

The voles were released through a series of ‘soft’ and ‘hard’ releases along the bank over the course of the week. Volunteers from the Ver Valley Society and Herts and Middlesex Wildlife Trust transported the voles in pairs to pens set out along the river bank for soft releases. The voles are reintroduced in this way to allow them time to settle into the new environment. After a few days of supplementary feeding with fruits and vegetables, the pens are removed and the voles will make their own burrows below the water’s surface. Hard releases on the other hand are for a few solitary voles which are released directly onto the river bank.

Chairman of the Very Valley Society John Pritchard said: ‘The Society is delighted to have been involved in this wonderful initiative. We have long been campaigning for the return of the River Ver’s former flow and wildlife and the reintroduction of water voles is one of the highlights of that journey. Over 40 volunteers have enjoyed every minute from the initial planning a number of years ago, to installing the pens and daily checks before finally opening the doors to see the voles go free.’

Water voles are part of a wider decline in our wild species and habitats across the UK. In Hertfordshire, one-fifth of the wildlife assessed in Hertfordshire’s State of Nature Report, published by the Trust in 2020, is currently either locally extinct or threatened with extinction. Habitat loss and fragmentation have sent populations plummeting. The report concludes that at least 30% of land must be protected for wildlife in order to combat the ecological and climate crisis.