Hazel dormouse, muscardinus avellenarius
I thought I would start a series of species profiles with the hazel dormouse, as over the last few years I’ve spent quite a bit of time monitoring them, and they are just about the cutest creatures in existence. (If you’re not sure you agree with that, watch this and then tell me what is cuter).
Hazel dormice are small, nocturnal mammals that spend most of their lives up trees, so few people get to see them in the wild. They have quite a varied diet, depending on what’s available at the time, including small insects, pollen, fruit, and nuts. They get the first part of their name from their fondness for hazel nuts. They live in woodlands, and prefer woods with a wide range of trees and a good understory, so food is available for them all the period they are active. Hedges are also important for them, both as a source of food and as a corridor between woodlands.
Dormice seem to enjoy proving dormouse experts wrong, so are sometimes found in unlikely places, including conifer plantations and small strips of wood between the carriageways of the A30.
Hazel dormice are the only dormouse species that is native to the UK, although there are a few rogue glis glis (edible dormice) (a much bigger, more troublesome type) in a small part of the country. (By the way, edible dormice really need to work on their branding – having ‘edible’ as part of your name has got to be bad news… how about adding an ‘in’ to the start of ‘edible’?)
While the dormouse’s range used to cover much of the UK, it is now largely confined to the south of England, with a few small pockets further north. This is thought to be largely due to habitat loss and fragmentation. Because of this, they are protected by legislation that means that you must not catch or disturb dormice without a licence. Any developments that threaten areas where dormice live must put in place mitigation measures to compensate for the damage caused.
Unlike other types of mice, they are not prolific breeders. Mature females will usually have 1 litter of around 4 young per year. Survival of these young depends on enough food being available for them to fatten up before hibernating.
Dormice are not the most active creatures. They spend about 6 months of every year hibernating. Even when they’re not hibernating they go into a state of torpor (very deep sleep) when it is a bit chilly (like the snoring chap in the video).
The People’s Trust for Endangered Species coordinates the National Dormouse Monitoring Programme, which keeps track of how the dormouse population is doing.
If you would like to learn more about these adorable creatures, I can recommend the following:
- Surrey Wildlife Trust‘s dormouse course – they run it once a year, so keep an eye out for it
- Dormice by Pat Morris: an accessible book focusing on Hazel dormice and edible dormice in Britain.
- The Hazel Dormouse by Rimvydas Juškaitis & Sven Büchner: a scientific monograph summarising what is known from studies of the hazel dormouse in Europe.
If you would like to help dormice:
- Sponsor a dormouse: sponsoring a dormouse through Surrey Wildlife Trust will help to pay for new dormice nest boxes and maintain existing ones, which are important for both monitoring the species and giving them suitable nest sites for breeding.
- If you are interested in getting involved in monitoring dormice, it’s a good idea to go on a course about dormice first (Surrey Wildlife Trust, Wildwood in Kent and the Mammal Society all run courses). Regular box checks are run by Surrey Dormouse Group and Kent Mammals Group
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