Mammal Week 2019 - Dormice
Dreaming of dormice
by Lorna Griffiths
Adorable, big-eyed, sleepy furball or grumpy, bitey, snarly furball: which would you choose? Me, I chose both. It all began back in 2008 when I happened upon a flyer pinned to a noticeboard “The Lincolnshire Dormouse Group Needs You”. I took down the details, and a few weeks later found myself in a Lincolnshire woodland with a stranger’s hands down the back of my trousers. Horrified? No, I was having one of the most memorable moments of my life, for I had just witnessed something that has become all too familiar, a baby hazel dormouse running up the inside of my trouser leg. That tiny little soul stole my heart and ever since I have spent almost all my spare time studying these charismatic creatures.
Following a presentation that I delivered at the National Dormouse Conference in 2013, I was invited to attend an edible dormouse survey in the Chilterns, five years on and I continue to attend monthly monitoring sessions on these non-native dormice. In 1902, a small population of edible dormice were thought to have escaped from a private collection in Tring and established themselves in nearby woodlands. Being a species that favours beech woodlands, the animals thrived in the beechwoods of the Chilterns and have become well-established in the area.
During the week I work as an ecological consultant, specialising in mammals, but at the weekend you will either find me gazing adoringly at a placid little hazel dormouse sitting calmly in my hand, or donning a pair of thick gauntlets whilst wrestling the brutish beast that is the edible dormouse.
Both species are nocturnal, primarily arboreal and hibernate over the winter months. However, this is where their similarities end, having adopted completely different life strategies. The hazel dormouse tends to breed once or twice each year, with small litters averaging four young, whereas edible dormouse breeding is closely correlated with beech mast, and therefore in years when beech nuts are scarce, breeding is either significantly reduced or even non-existent. To counteract non-breeding years, large numbers of young are produced during high-fruiting years, with some animals producing up to eleven pups.
Size and weight differ enormously between species. The heaviest hazel dormouse that I have encountered was a 38g female in a Nottinghamshire woodland, a pinprick compared to the 350g edible brutes that I have met in the Chilterns.
Over the winter months you will find the hazel dormouse tucked up in a tiny woven nest below leaf litter, at the base of a coppice stool or beneath log piles. Edible dormice favour a different tactic, opting to hibernate below ground in rabbit burrows, disused badger setts and holes created by rotten tree roots. Although both species have a propensity to hibernate alone, on occasions the edible dormouse has been found to hibernate communally with one or two others.
If you take a walk in a Chilterns woodland at night, you may be lucky enough to hear the vocalisations of edible dormice echoing loudly through the trees. The hazel dormouse on the other hand is far more discreet, with barely audible whispers, often undetected by the human ear.
One obvious difference between the two species is the colour, one is golden brown, the other silver grey, and finally, their temperament. The hazel dormouse is British through and through, with impeccable manners, patience and good grace, whilst the non-native edible dormouse is terribly impolite, impatient and is prone to temper tantrums. However, despite their roguish nature, one has to appreciate the tenaciousness of the edible dormouse…preferably from afar, and with full body armour. My heart though, will forever belong to the sweet-tempered, especially endearing, hazel dormouse.
Get involved!
Autumn and winter are the best times for searching for hazel nuts as the vegetation is scarce and nuts are easier to find discarded on the ground. Different species of small mammals leave distinctive markings on hazel nuts, meaning you can identify which creature nibbled the nut!
Hazel dormouse: opening has a smooth inner rim with tooth marks on the outside of the nut at an angle to the hole
Voles: tooth marks across the inner rim of the nut but don’t leave any marks on the out of the opening
Mice: tooth marks both on the inner rim of the nut and also on the surface, around the edge of the hole
Squirrels: usually just cracked in half, no obvious 'opening'
So why not go on a Nut Hunt this autumn and let us know what you find using our Mammal Mapper app? If you take a really clear photo of the openings on the nuts you find and add these to your Mammal Mapper records then we can easily verify your records and add them to our system confidently. Going on a nut hunt is a fantastic way to spend a day outside in nature. You can also check out a handy Nut Hunt guide from PTES here.
Just like Lorna mentions at the start of the blog, you may find that a local dormouse group needs your help! If you're keen to help out, consider contacting a group to see if they need any help. These are the groups we know about:
Nottinghamshire dormouse group
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Go to our National Mammal Week page to find out what's happening each day this Mammal Week! Make sure you are following #MammalWeek and #MammalsMatter and keeping an eye on our social media feeds for all things Mammal Week related. You wouldn't want to miss out on our prizes would you?! |