The dormouse (Muscardinus avellanarius) is a shy, secretive, nocturnal mammal usually associated with broadleaved woodland, ancient hedgerows and old orchards.

The dormouse requires a very ‘species rich’ habitat and they have a varied diet that includes the nectar and pollen of flowers, fruit, berries and nuts. Food sources must be present within a comparatively small area, as they will not normally travel much more than seventy metres away from their chosen nest site. The species occurs in a population density of no more than ten adults per hectare and they can live for up to five years. They may raise one or two litters, usually of around four young, each year.

They differ from other mice and have a characteristic long bushy tail, attractive golden-brown fur and prominent black eyes. Adults weigh between 16-22g although this increases to about 30g prior to hibernation. Hibernation usually takes place between October and April on or near the ground in a nest under vegetation or between tree roots. During hibernation body temperature approaches that of its surroundings and heart and breathing rates drop by 90% or more. The dormouse has the ability to enter temporary torpid states during the summer if temperatures drop or there is a scarcity of food. This ability has probably resulted in its reputation as being ‘sleepy’, as illustrated in the famous mad hatter tea party scene in the Alice in Wonderland story.

Nationally, the dormouse has declined and disappeared from around half of its former range in the last hundred years or so. However, there has been much effort to manage woodlands where it still occurs in ways that encourage a rich habitat. Coppicing, for example, helps to retain the diversity necessary.

From an article by Paul Terry, Environmental Officer at Southend-on-Sea Borough Council