Hazel dormouse Muscardinus avellanarius

Dormouse (c) Tom Chalmers

Species information

Common name: Hazel dormouse

Latin name: Muscardinus avellanarius

Category: Mammals

Statistics: Length 8cm plus a tail of 6cmm/ Weight 15-40g/Average lifespan 4 years

Conservation status: Classified as a Priority Species in the UK Biodiversity Action Plan.


The hazel dormouse is an agile climber and mainly nocturnal so is rarely seen. They live in deciduous woodland, hedgerows and dense scrub and spend most of the spring and summer up in the branches rarely coming down to the ground. They eat buds, hazelnuts, berries and insects.

They build summer nests of grasses, stripped honeysuckle bark and fresh hazel leaves in which the female will give birth to up to seven young. They hibernate during the winter months, either on the ground - under logs, leaves, in grass tussocks and at the base of trees - or just beneath the ground where the temperature is more constant.

How to identify

The dormouse has gingery-brown fur, large black eyes and a fluffy tail; it is much smaller than a Squirrel.

Where to find it

Southern England and Wales.




When to find it


How can people help

The hazel dormouse is suffering from the loss and lack of management of its preferred habitats (woodland, hedgerows and dense scrub). It is also thought displacement by the introduced edible dormouse (Glis glis) is a problem in the Chilterns. Gloucestershire Wildlife Trust is helping by monitoring dormice populations, providing nestboxes and actively managing their preferred habitats appropriately through the Dormice in Danger Appeal. Coppicing, ride widening, thinning and glade creation in woodland creates the successional stage of woody vegetation preferred by dormice. Please help us carry out this vital work by donating to our appeal.