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 said: "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 contacted 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.

With support from Whitby Naturalists’ Club and the Yorkshire Rewilding Network, they began planning the release of the mice, which were captive-bred especially for the project by Derek Gow and his team. Volunteers from these groups were invited to help with the release and will also assist with future surveys to assess the success of the reintroduction.

Asked if she had any advice for those considering rewilding a proportion of their garden or land for nature, Hilary said: b“People might think it’s about doing nothing, but actually it’s about handing some of the control to nature whilst trying to create as much variety as possible. For us, it’s been an ever-evolving source of fascination and learning.”

If you’d like to read more about Hilary and Steve’s journey, Hilary has written a number of guest blogs (entitled ‘An unexpected journey’) for Yorkshire Rewilding Network. Visit yorkshirerewildingnetwork.org.uk/guest-blog

To find out more about the Farming in Protected Landscapes scheme, or other types of grants and advice available in the North York Moors National Park, please visit northyorkmoors.org.uk/grants