A top secret woodland location on the outskirts of Royal Leamington Spa became the brand new home for some charming yet endangered inhabitants.

The hazel dormouse – now extinct in 17 English counties – was reintroduced to Warwickshire on Tuesday (June 20) as 18 breeding pairs, plus one extra female, were released by People’s Trust for Endangered Species (PTES), Warwickshire Wildlife Trust and some dedicated and willing volunteers.

These dormice will spend the next 10 days in their purpose-built mesh cages where they will be checked and fed by volunteers whilst they learn to gather food themselves. When they are ready to be released, a small door will be opened in the cage to allow them to access the woodland, whilst still benefiting from the safety of their nesting boxes.

Given that hazel dormice (Muscardinus avellanarius) will generally only produce one litter a year averaging just four young, it’s no surprise these charismatic little creatures are struggling for survival.

They face pressures from lost habitats and changes in woodland and hedgerow management – as the practice of coppicing trees such as hazel, hornbeam and sweet chestnut has become more rare, so too have the dormice.

This secret Warwickshire location was selected based on its excellent suitability for the new residents. Being both arboreal, and nocturnal, the dormice rely on tree cover, using the branches to travel through the canopy and through shrub layers.

As they were released into their new homes, they were given a selection of berries, dried fruits, mealworms, and other dormouse delicacies but over coming weeks, they will learn to forage for themselves.

Since 1993 PTES has reintroduced more than 898 hazel dormice in 22 different sites across England.

Leading this latest reintroduction, Ian White, PTES’ Dormouse Officer said: “Climate change is one factor having a serious impact the dormice population, but the biggest issue is woodland management.

“At this site the management of woodland will have to continue to ensure the dormice can thrive. They need successional vegetation and all the video evidence we have shows they actively look for that arboreal cover.”

Before the dormice were released they had to be reared, quarantined and health checked by various volunteers and organisations. They were captive bred by members of the Common Dormouse Captive Breeders Group, of which Neil Bemment is the chairman. Neil has been rearing dormice and attending release events since 2000. He says: “When the dormice are two years or under we pair them up, ensuring they are genetically matched – as far from being related as we possibly can. We aim to release 18 pairs each year. We are trying specifically to reinstate them in the counties where they would have originally thrived.”

The dormice underwent thorough health checks with vets at the Zoological Society of London and Paignton Zoo in Devon, ensuring they would had the very best chance of survival and also in a bid to prevent the accidental introduction of any new diseases to the wild. They will continue to be closely monitored and it is hoped that they will have settled and paired up in just two weeks – with baby dormice born by the end of the year.

And funding of £1 million from the Heritage Lottery Fund will ensure that this reintroduction programme can continue for the next four years, as part of a bigger project – the Princethorpe Woodlands Living Landscape Scheme – whose stated objective is to bring ancient woodlands back into management, to work with landowners to better connect the woodlands, to restore hedgerows, and to engage the public.

Chris Redstall, Scheme Manager, explained: “There are 300 nest boxes around the wood and they will be checked by volunteers who have a dormouse licence. Long term we just want to see a stable population. There is likely to be a growth spurt at around three years, and then the population stabilises. That is what we hope for.”

PTES manages the National Dormouse Monitoring Programme, which is co-funded by Natural England. Dormice can be monitored by checking nesting boxes and by checking nut consumption since the way a dormouse chews a hazelnut is unique. (They will open the nuts whilst still green and on the tree, and the shells only turn brown once they are discarded and fall to the ground.)

The reintroduction is a timely event as it coincides with the publication of new research by the University of Exeter highlighting the creature’s steep decline over the past 20 years. With numbers plummeting by more than 70 per cent, the study – published in the journal Mammal Review – shows that the cause of decline is not well understood but that woodland management could be a significant key factor. The paper entitled Voluntary recording scheme reveals ongoing decline in the United Kingdom hazel dormouse population was supported by the Forestry Commission and Natural England, and further supports the importance of reintroduction schemes such as the one I witnessed this week.

In a county where this delightful animal was once extinct, this latest reintroduction hopes to build on the success of earlier ones but also to foster better engagement between landowners and wildlife organisations, encourage better management of the land and to eventually see the native hazel dormouse quietly thriving.

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Laura Briggs is a regular contributor to the Ecologist. Follow here here: @WordsbyBriggs