9 Jun 2023

Over 20 years ago we began a mission to bring the iconic harvest mouse back from the brink of extinction in the UK. We’re thrilled to share this conservation success story alongside our brand new flagship film, showcasing the conservation hero behind the tale.

Harvest mice are one of our most beloved animals in the UK. They’re the only British mammal to have a prehensile tail and are one of our tiniest mammals, weighing less than a 2p coin. Despite their small size, they play a huge role in our ecosystems and are vital to protect.

Scientists completed harvest mice surveys across England between 1980 and 2000 and found that they were in trouble. This is, sadly, still true today, with the adorable rodents still being a conservation concern in the UK as they’ve continued to experience big declines in recent years, mainly due to a loss of habitat and more intensive farming methods. As a result, they’re a ‘priority species’ under the UK Post-2010 Biodiversity Framework.

A remarkable rescue

We made it our mission to help this species. Our team of dedicated conservationists set up an experimental breed and release programme to help inform potential reintroduction efforts across the country at the turn of the millennium. Following strict scientific protocols set up by the International Union for Conservation of Nature, we released a staggering 960 harvest mice between 2002–2004 to help save this vulnerable mammal from extinction.

Amazingly, over two decades later, we’ve confirmed that the descendants of those harvest mice are now thriving in and around our Nature Reserve! In fact, we found 69 breeding nests in 2022 and 118 in 2023. These numbers are hugely significant, representing just under 10% of Great Britain’s total breeding nests in 2021–22, as reported by the Mammal Society.

The release was led by our wonderful Registrar, Penny Rudd, who has championed the conservation of harvest mice throughout her 42 years working at the zoo and personally microchipped all 960 mice during the release.

Penny Rudd | Registrar at Chester Zoo

“I think every species should have a champion, and I’d like to feel I was the champion for harvest mice back in the turn of the century.”

“What the story tells you is that, if you champion a species, you can inspire others to join you and you can actually make a difference, because it has made a difference – we have clearly succeeded!”

Helen Bradshaw, our fantastic UK Regional Field Programme Manager here at the zoo, said:

Chester Zoo's Helen Bradshaw planting sea holly in the UK

“As one of the first breeding and reintroductions programmes that Chester Zoo embarked on 20 years ago, it’s hugely significant to be able to prove that it worked, and we’re delighted that the harvest mice are thriving in our Nature Reserve and surrounding areas.”

“Our Nature Reserve is a flagship landscape for our efforts to recover local biodiversity, and our UK Field Programmes team will continue to manage and improve our habitats in this area for all our native species. Importantly, we’ll also continue to carefully monitor the harvest mouse populations as these data contribute to efforts by The Mammal Society to build up a national picture for this iconic little mouse. With biodiversity in decline across the UK and many species here on the brink of extinction, collecting standardised data is vital to help us create effective strategies that protect and connect habitats.”


While our conservationists are working hard to monitor and conserve harvest mice in our Nature Recovery Corridor, we can all play our part in protecting them by helping local wildlife charities with harvest mice nest surveys, recording sightings to the Mammal Society and wildlife record centres, and leaving long-grass and bramble-patches in gardens and local parks. By working together, we can ensure these animals have a future on our wild isles.

This heartwarming conservation tale not only shows the importance of individual and collective efforts in restoring and protecting wildlife, but also that there’s hope for us to reverse the ongoing biodiversity crisis.