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Rare dormice return to Yorkshire Dales National Park

Home // News // Rare dormice return to Yorkshire Dales National Park

Wildlife charity People’s Trust for Endangered Species (PTES) and the Yorkshire Dales National Park Authority are today [Thursday 23 June] releasing 38 rare hazel dormice (Muscardinus avellanarius) into an undisclosed woodland location near Aysgarth in the National Park in an attempt to stem the decline of the species.

Once a familiar sight throughout much of England and Wales, over the past 100 years dormice have suffered from the loss of woodlands and hedgerows, as well as changes to traditional countryside management practices. As a result, the species is now rare and vulnerable to extinction.

The reintroduction follows a similar event in 2008, when dormice returned to a nearby woodland after a century’s absence from the Yorkshire Dales.

PTES has worked in partnership with the National Park Authority and Bolton Estate to carefully select a suitable new site near the 2008 location which will provide the best chances for the long-term survival of the species.

Ian White, Dormouse Officer at PTES explains: “The two reintroduction sites are close enough that the separate dormice populations will eventually be able to meet up and breed, creating a self-sustaining population. In addition, the programme of habitat management in the area will have great benefits for a number of other species too such as birds and bats.”

Ian Court, the National Park Authority’s Wildlife Conservation Officer, adds: “It is fantastic that we are undertaking this additional release that will help build on the original successful re-introduction in the heart of Wensleydale.

“We look forward to working with landowners and managers to help create a network of managed hedgerows and woodlands within the lower Wensleydale area that will look to re-establish a species back into the Yorkshire Dales that has been missing for many generations.”

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

The release marks the culmination of weeks of work by all of the partners involved in the different stages of the reintroduction process, which also include Natural England, Zoological Society of London, Paignton Zoo, Common Dormouse Captive Breeders Group, and the Bolton Estate.

The dormice that will be released have been captive bred through the Common Dormouse Captive Breeders Group. Prior to release, the dormice undergo a six-week quarantine at Zoological Society of London (ZSL) and Paignton Zoo in Devon, during which vets conduct a full health examination to check they are in top condition and reduce the risk of them passing non-native disease, ensuring they have the best chance of forming a healthy population in the wild.

Following the health checks, the dormice are then released on-site in breeding pairs or trios in their own wooden nest box fitted inside a mesh cage secured to trees. The mesh cages, filled with food and water, help the dormice adjust to their new home in the wild. The cages are eventually removed once the animals have settled into the wood.

This year marks the 26th dormouse reintroduction led by PTES, with more than 750 dormice released at 19 different sites across 12 English counties over the last two decades.


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For more information, images, or interviews contact Susannah Penn or Adela Cragg at Firebird PR on 01235 835297 or or @firebird_pr

There will be live updates about the reintroduction throughout the day, follow People’s Trust for Endangered Species on Facebook or @PTES and #dormouseday on Twitter



Supporting quotes

Tom Orde-Powlett, manager, Bolton Estate

“We are delighted to support the national dormouse reintroduction programme. Conservation is central to our work and lives at Bolton and we are very proud of the wildlife that thrives here. We look forward to continued work with the National Parks and other partners to increase biodiversity, alongside protecting the many existing species of flora and fauna that we are so privileged to enjoy.”

Tony Sainsbury, Senior Lecturer in Wild Animal Health, Zoological Society of London

“The health of reintroduced species must be managed carefully to ensure that harm to the dormice and other woodland species is avoided.  In this programme we invest considerable resource to evaluate the health of the hazel dormice health before reintroduction to endeavour to develop a healthy ecosystem.”

Neil Bemment, Chairman, CDCBG & Curator of Mammals, Paignton Zoo

“We are really pleased to have been able to support yet another year of the Species Recovery Programme by providing dormice for release. The individuals concerned have been carefully selected according to studbook recommendations by one of the CDCBG members, namely Wild Wood in Kent. All in all it is a great example of cooperation between a range of organisations and landowners for the greater good one of our most charismatic native species.”  

About PTES

PTES is a UK conservation charity created in 1977 to ensure a future for endangered species throughout the world. Working to protect some of our most threatened wildlife species and habitats, it provides practical conservation support through funding research and internships; providing grant-aid for world-wide and native mammals species conservation; supporting education, training and outreach programmes; and driving public participation via wildlife monitoring surveys, publications, campaigns and events. Priority species and habitats include hazel dormice, hedgehogs, water voles, noble chafer and stag beetles and traditional orchards and native woodlands. Visit or @PTES.

About the National Dormouse Monitoring Programme (NDMP)

The NDMP is co-funded by People’s Trust for Endangered Species and Natural England and has been running for over 25 years over 400 sites. It is one of only a handful of mammal programmes contributing long-term data on population trends. The NDMP relies completely on the enthusiastic commitment of volunteers who collect dormouse data annually at over 300 monitoring sites all over the country. Dormice population numbers and density in their remaining range are monitored by putting up nest boxes similar to bird boxes on hazel trees and checking the boxes for occupancy at regular intervals. The results are held in a database which is used to assess the status of the species over time.

About the Species Recovery Programme

Natural England’s Species Recovery Programme (SRP) takes targeted conservation action for species in rapid decline or at greatest risk of extinction. Through this programme we work with a wide range of partners to understand and reverse the declines or extinction of some of our most threatened wildlife. Work includes research and monitoring to identify the needs and ecology of individual species, trialling land management solutions, establishing captive breeding or propagation programmes, and undertaking practical action, including reintroductions, to help species populations to recover.

About Natural England
Natural England is the government’s advisor on the natural environment. Established in 2006, our work is focused on enhancing England’s wildlife and landscapes and maximising the benefits they bring to the public. For more information, visit: @NaturalEngland or

About ZSL

Founded in 1826, the Zoological Society of London (ZSL) is an international scientific, conservation and educational charity whose mission is to promote and achieve the worldwide conservation of animals and their habitats. Our mission is realised through our ground-breaking science, our active conservation projects in more than 50 countries and our two Zoos, ZSL London Zoo and ZSL Whipsnade Zoo. For more information visit

About Paignton Zoo

Paignton Zoo is not just one of the UK’s top zoos and a great day out; we are also a conservation and education charity and part of a group of zoos and charities. The Zoo was founded in 1923 by Herbert Whitley, and when he died in 1955 the Whitley Wildlife Conservation Trust was set up in his name. Paignton Zoo is owned by the Trust and it also owns Living Coasts in Torquay, Newquay Zoo in Cornwall, Primley Park and Clennon Gorge in Paignton, and Slapton Ley National Nature Reserve.

About Yorkshire Dales National Park

The Yorkshire Dales National Park is one of 15 National Parks in the UK. It is administered by the Yorkshire Dales National Park Authority, which has two main purposes: “to conserve and enhance the natural beauty, wildlife and cultural heritage” and “to promote opportunities for the understanding and enjoyment of the special qualities of the National Park”. In carrying out these purposes, the Authority has a duty “to seek to foster the economic and social well being of local communities”. The National Park Authority comprises 22 members, made up of county and district councillors and members appointed by the Secretary of State for the Environment to represent parishes or in recognition of their specialist skills or knowledge.

About the Common Dormouse Captive Breeders Group

The Group keeps and breeds the animals that go into the reintroduction sites.

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