Dormouse (Muscardinus avellanarius)

Deciduous woodland, Mixed woodland and Coniferous woodland.

Orange/yellow fur; our only small mammal with a very distinctive thick furry tail. Large eyes and ears (because it is nocturnal); Paws turn sideways (for climbing).

60-90mm, tail 57-68mm

10-15g in juveniles; 15-26g in adults, up to 43g before hibernation.

Origin and Distribution
Dormice occur mainly in southern counties, especially in Devon, Somerset, Sussex and Kent. There are few recorded localities north of the Midlands, though they are present in parts of the Lake District and in scattered Welsh localities. The dormouse is found in deciduous woodland and overgrown hedgerows.

General Ecology
The dormouse is a strictly nocturnal species, found in deciduous woodland and overgrown hedgerows. It spends most of its time climbing among tree branches in search of food, and rarely comes to the ground. During the day it sleeps in a nest, often in a hollow tree branch or a deserted bird nest or nest box. Dormice are able to lower their body temperature and become torpid, so saving energy, if food is short or weather prevents them foraging. During the winter they hibernate and are not normally active again until April or May. Thus dormice may spend three-quarters of their year ‘asleep’.

Dormice live at low population densities (one tenth as abundant as bank voles and wood mice in the same habitats).

Dormice feed on flowers, pollen, fruits, insects and nuts.

Up to five years.

They can raise one or occasionally two litters a year, each usually of about four young. The new-born dormice remain with their mother for 6-8 weeks before becoming independent. The breeding season and success depends very much on the weather.

Conservation Status
Dormice are strictly protected by law and may not be intentionally killed, injured or disturbed in their nests, collected, trapped or sold except under licence. Their principal requirement is for a diverse habitat featuring several different trees and shrubs to provide food throughout the summer. Coppice management of wood-lands can create such conditions; but cleared areas and wide rides may interfere with the movements of dormice, because the animals live almost exclusively in the trees. Surveys show dormice have declined in Britain this century. Loss and fragmentation of ancient woodlands, climatic difficulties and suspension of coppicing are all probably connected with this. Nest boxes, put up with the entrance facing a tree trunk, are attractive to dormice and help survival and breeding success.

Re-introductions of dormice are often suggested, but these require suitable (large) areas of woodland habitat and long periods of supplementary feeding. Breeding dormice in captivity is difficult and wild-caught animals are unlikely to be available in sufficient numbers. If fewer than 20 animals are released there is a high risk of failure. However, they have been success-fully reintroduced since 1992 to several counties (including Cheshire, Cambridgeshire, Derbyshire).

Many thanks to the Mammal Society for sharing the information, for more details on the Society please visit their website below:

Credit: With thanks to The Mammal Society for providing the photo and information. © The Mammal Society