Eleven hazel dormice released into an undisclosed woodland location near Retford, in Nottinghamshire.

The People’s Trust for Endangered Species (PTES) State of Britain’s Dormice 2016 report confirmed that hazel dormice had disappeared from 17 English counties since the end of the nineteenth century, and that recent records reveal populations have probably fallen by a third since 2000.

Loss of woodland and hedgerow habitat, as well as changes to traditional countryside management practices, are all factors which have caused this decline.

Dormouse stronghold

The release of 11 dormice this week will bolster the existing reintroduced populations of hazel dormice already in the area by increasing genetic diversity and therefore helping the long-term survival of this endangered species.

The release follows three previous reintroductions which took place in 2013, 2014 and 2015. These three woodlands are all owned by the Nottinghamshire Wildlife Trust and are located within a five-mile radius of each other.

Ian White, Dormouse & Training Officer at PTES explains: “This week’s release is the next phase of a wider landscape project, as this site was where we released 40 dormice. Over the last five years, we’ve reintroduced over 100 hazel dormice into this part of the county, in three different woodlands.

“By releasing more dormice again this year, we hope to achieve our aim of connecting the three separate populations and increasing the gene pool, consequently creating a dormouse stronghold in the region.”

Ian continues: “Since the previous reintroductions, dormice have become well dispersed throughout all three woodlands, which is fantastic as it shows they have adapted and settled into their new surroundings.

“To ensure these populations continue to thrive, each woodland will require ongoing woodland management, which is something our colleagues at the Nottinghamshire Wildlife Trust and Nottinghamshire Dormouse Group have been doing successfully since 2013.”

Smooth transition

This release and previous reintroductions would not be possible without weeks of hard work by partners PTES, Nottinghamshire Wildlife Trust, Nottinghamshire Dormouse Group, Natural England, ZSL (Zoological Society of London), Paignton Zoo and the Common Dormouse Captive Breeders Group. Each are involved in the different stages of the dormouse reintroduction:

All dormice being released this week are captive bred by members of the Common Dormouse Captive Breeders Group

Prior to release, the dormice undergo a nine-week quarantine period at ZSL London Zoo and Paignton Zoo in Devon, during which vets from both institutions conduct a full health examination to check they are in tip-top condition and to reduce the risk of them passing on non-native diseases, so that they have the best chance of forming a healthy population in the wild

Once all dormice have been given the green light, they are carefully transported to the reintroduction location, where staff from PTES, Natural England and members of Nottinghamshire Dormouse Group, will be on hand to ensure the smooth transition from travel nest-boxes to their new woodland home

New home

Tony Sainsbury, Senior Research Fellow, ZSL and lead Disease Risk Analysis and Health Surveillance (DRAHS) Project (NE and ZSL) explains: ”The health of all species being translocated needs careful management and monitoring both before and after the release. 

“The effects of squirrelpox virus on red squirrel populations in England, and the chytrid fungus on amphibians worldwide, provide warnings of the dangers of unplanned translocations.

“At DRAHS we are pleased to have been monitoring the health of reintroduced dormice throughout England for nearly 20 years.”

After the reintroduction, the dormice spend the next 10 days in large release cages, which are checked daily and are connected to trees containing natural foliage, food and water to help the dormice become acclimatised to their new surroundings.

After this, a small door in the cages are opened, leaving the dormice free to explore their new home. Eventually, the release cages are removed once the dormice have settled into the wood.

Great success

Lorna Griffiths, Chair of the Nottinghamshire Dormouse Group adds: “Not only have the dormice dispersed throughout their original release sites, but also populated nearby woodlands, increasing their stronghold in the wider landscape.”

Michael Walker, Reserve Management and Monitoring Officer at Nottinghamshire Wildlife Trust, says: “The introductions in Nottinghamshire have been a great success and these extra animals will help to ensure that their future is secure as they venture out into the wider landscape.”

A second release is also taking place in Lincolnshire this week, where another 11 dormice will be released. This follows a previously successful reintroduction in 2002, so this addition will also strengthen the local dormice population in this area.

These reintroductions play an important role in the long-term conservation of this endangered species and are part of the Species Recovery Programme supported by Natural England.

This year’s two releases are the latest in the programme, which has run for over 25 years, releasing almost 1,000 hazel dormice (the majority of which were bred by the Common Dormouse Captive Breeders Group) back into 12 English counties where dormice once existed, in an effort to rebuild lost populations.

Healthier population

Dr Peter Brotherton, Director, Specialist Services and Programmes, Natural England concludes: “We have seen great success in reintroducing hazel dormice to Nottinghamshire and Lincolnshire though our Species Recovery Programme, and today’s release will mean their numbers can grow.

“This project is helping to maintain woodlands and the links between habitats to allow our dormouse communities to breed and create a healthier population.”

This Article 

This article is based on a press release from the People’s Trust for Endangered Species.