Heroes to the harvest mouse: 300 tiny mammals released in the North York Moors National Park - North York Moors National Park

More than 300 harvest mice have been released at a site in the North York Moors National Park in the hope of re-establishing a local breeding population of this once-common species.

The initiative, led by Hawsker residents Steve Mills and Hilary Koll, has been supported by a grant of £4,200 from the Defra-funded Farming in Protected Landscapes scheme.

The release follows several years of habitat restoration by Steve and Hilary, who have been working with Derek Gow Consultancy – experts in UK small mammals – to ensure the right environment for the mice. The couple purchased the ‘wild and windy’ pasture field around five years ago, and have since planted trees, built ponds and watched as a habitat full of birds, butterflies and bees has slowly developed. It was a chance bit of research, however, which led Hilary down the path of harvest mice reintroduction. Hilary recalls:

"In different patches of the field, we noticed a certain type of grass – cocksfoot - started to dominate. In researching this grass, it turned out to be the species most favoured by harvest mice, and so there our journey began!”

Harvest mice, once a widespread species in the UK, are now classified as Near Threatened and are on the Red List of British Mammals. These tiny creatures, which weigh about the same as a two-pence piece, are highly vulnerable to predators such as cats, owls, and crows. They rely on dense vegetation, such as long grass and reeds, to build their distinctive woven nests.

Steve and Hilary made contact with others who have an interest in this area, learning that while there was no evidence of harvest mice currently living around their land, there certainly are harvest mice living successfully elsewhere in the North York Moors.