Natural England - Dormouse reintroduction in Warwickshire

Dormouse reintroduction in Warwickshire

20 June 2012

One of Britain’s most endearing but elusive mammals - the hazel dormouse Muscardinus avellanarius – returns to Warwickshire.

Hibernating dormouse © John Robinson

Hibernating dormouse © John Robinson

A new reintroduction programme - starting today - is led by the People’s Trust for Endangered Species (PTES), with funding from Natural England.

Thirty-four captive-bred dormice will be released into the wild at a private woodland in Warwickshire. The semi-ancient natural woodland at this latest reintroduction site has a mix of plant species – hazel, oak, hawthorn, bramble, ash, elder, silver birch, field maple and wild service tree among others – all of which provide an excellent source of food and shelter for breeding dormice throughout the seasons. 

The dormice were captive bred through the Common Dormouse Captive Breeders Group and have been checked with vets at Zoological Society of London and Paignton Zoo in Devon to make sure they were healthy and have the best chance of survival.  They will be released in pairs in their own secure wooden nest box fitted inside a mesh cage secured to woodland trees.  This helps them adjust to their new home in the wild.  Once the initial relocation has taken place, the dormice will be checked and fed daily in these cages over a two week period to help acclimatise them to their new environment.  A small door in each cage is then opened so that the dormice are free to explore their new home whilst having the security of the mesh cage and food if needed.  These are eventually removed once the animals have settled into the wood.

Katherine Walsh, Mammal Specialist at Natural England added; “Dormice are a charismatic, iconic creature of our countryside but their numbers have fallen significantly since the late 19th century. We set up the dormouse recovery project nearly twenty years ago, which has seen dormice return and thrive in many areas of the country where they had become extinct. This is the 18th reintroduction by PTES at a specially selected site in England - we are delighted to support the scheme and wish it every success.”   

Nida Al-Fulaij, who coordinates the reintroductions at PTES, explains: “There is good news and bad about dormice. The bad news is that despite their once widespread existence throughout much of England and Wales, there has been a dramatic 40% decline in their population numbers over the last two decades and they are now rare and vulnerable to extinction.  The good news is that analysis from the National Dormouse Monitoring Programme suggests that although dormice continue to decline, the rate of decline may be slowing.  This gives us every reason to double our efforts for dormice with renewed confidence and enthusiasm that we are doing something right, and reintroductions are a key aspect of those efforts.”

More than 635 dormice have been released across 12 English counties over the last 19 years as part of the National Dormouse Monitoring Programme. Survival rates of dormice reintroduced into the wild are extremely high, with dormice from several sites, known to have dispersed beyond the woodland in which they were released. Reintroductions are only attempted in areas where historical populations of dormice have gone extinct and are followed by ongoing sympathetic management of the woodland and hedgerows.

Hazel dormouse (Muscardinus avellanarius)