More than 150 harvest mice have been reintroduced to a west London nature reserve as part of a rewilding project.
The animals have returned to Perivale Wood having last officially been spotted at the site in 1979.
Harvest mice became locally extinct in Ealing over four decades ago but are now being released across the borough as part of a project by the Ealing Wildlife Group, made possible with funding from the Mayor of London and Amazon’s Right Now Climate Fund.
More than 1,650 harvest mice have now been released across sites in Ealing with Perivale Wood becoming the fifth release site.
It is thought that the mice disappeared due to the loss of their natural habitat and their populations have rapidly declined by 70 per cent across the UK since the 1970s.
Sections of meadows have been set aside in Perivale Wood to create wildlife corridors for the small mammals.
Grass will remain un-grazed to provide nesting material and cover for the mice and a new pond alongside an existing one will create additional reed bed areas, which the animals enjoy.
The mice were bred in captivity by volunteers.
Richard Goddard, from the Selborne Society, which manages the wood, said the reintroduction of mice was "fantastic".
He added: "Selborne Society volunteers put in more than 2,000 hours of voluntary work to improve our habitats.
"This has been the perfect way to celebrate National Mammal Week".
Dr Sean McCormack, vet and Chair of Ealing Wildlife Group commented: “It's been really fantastic to see wilder habitat types emerge in the past few years through our collaborative work with Ealing Council, meaning species that have previously been pushed to the edge now have the opportunity to return.
“Our Rewilding Ealing initiative has seen not only Britain's smallest native rodent, the Harvest Mouse reintroduced, but also our largest, the Eurasian Beaver. Both projects have now been helped by the Mayor's Rewild London fund.
“These projects are not just about rewilding habitat and reintroducing lost species, but also about rewilding people.”
Last year a family of beavers were also released in Ealing to encourage rewilding.
They were released by Mayor Sadiq Khan in an eight-hectare fenced area of wetland at Paradise Fields woods in Greenford.
It is thought to be the first time in 400 years that beavers have been seen on an urban site in the capital.
