THEY were immortalised in the Wind in the Willows, but numbers of the enchanting water vole have slumped in recent decades.
Now, they are set to flourish after being returned to a stretch of river where they have not been seen for more than 30 years.
The National Trust is to release some 150 of the mammals into the River Aller on its Holnicote Estate on Exmoor in Somerset, where they were last seen in the 1980s.
Their return is part of the charity’s £10m Riverlands project to restore five rivers across England and Wales, and it is hoped the voles will boost the wildlife of the waterways running through the Exmoor property.
It follows a similar scheme by the charity to release hundreds of voles at Malham Tarn in the Yorkshire Dales, which began in August 2016.
Water vole numbers have plummeted across the country in the face of loss of suitable habitat and because they are preyed on by invasive American mink which escaped or were set free from fur farms.
The 150 water voles are being released in groups of siblings and in breeding pairs at six sites on the river, from where they will be able to spread along the streams of the catchment.
A further 150 will be released in the spring.
National Trust South West conservation manager, Alex Raeder, said: “I remember being enchanted by these creatures as a child, and hugely welcome their return.
“This ambitious project not only brings back to its rightful home a much-loved small animal, which sadly became extinct due to human activity, but also adds to the whole wealth of wildlife and enjoyment of this wild and stunning estate.
“In true Wind In The Willows-style, these voles should soon be busy burrowing into the muddy banks and creating more natural-looking edges to streams with shady pools that are great for so many other small creatures.”