The release, undertaken as part of the wildlife charity’s Catch My Drift project, has been made possible thanks to a large private donation and further reinforces what is one of the few harvest mouse colonies north of the River Tyne.

The 185-hectare reserve, which is a haven for birds and other mammals, will hopefully prove a successful breeding ground for the cute animals, which weigh the same as a 10p coin.

The East Chevington site with its extensive reed beds provides a suitable habitat for the mice, which build distinctive circular grass nests on tall plants 3ft from the ground.

Joel Ireland, Catch My Drift project trainee said: “It’s great that we have been able to release another 100 harvest mice onto the East Chevington reserve, so fingers crossed the project will be able to create a stronghold in Northumberland for this wonderful mammal once again.”

The Catch My Drift venture at East Chevington is a three-year initiative backed by £418,000 from National Lottery players, via The National Lottery Heritage Fund, to improve the reserve’s habitats, species numbers and upgrade access to the Druridge Bay site, she said:

Although part of the wider Catch My Drift project, the release itself has been funded by a generous private donation.