Posted by: lensweb | September 28, 2019

What did LENS learn from the Nottinghamshire Dormouse Monitoring Group?

15 September Dormouse Monitoring

Leader Lorna Griffiths, Chair, Notts Dormouse Group at Treswell Wood near Retford.

We met Lorna Griffiths, Chair, Notts Dormouse Group with other members of the group at Treswell. She kept up a constant flow of information throughout a busy and exciting dormouse monitoring session in the wood.

Hazel dormice are adorable with red-brown fur, a long furry tail and big eyes (because they are nocturnal). They are native and should not be confused with the edible dormouse which is found in Surrey. The edible dormouse is an alien species which can have a devastating effect on the native fauna.

The first record of common or hazel dormice in Derbyshire was in 1882, but JW Carr’s 1900 Zoology of Nottinghamshire has no mention. There have been sporadic records up to a 1968 re-introduction of the species which was deemed to have been unsuccessful. It was not until after a second re-introduction under the strict guidelines of the Dormouse Monitoring Scheme, that it became known that there had been an occasional record of a dormouse at the original re-introduction site.

A dormouse introduction involves fixing a minimum of 50 nestboxes in a grid 10m apart in a managed hazel coppice with scrub and some oak, ash and birch canopy trees, like at Treswell Wood, This provides, nuts, fruit and invertebrate food throughout the year. Dormice are introduced by placing a pair in a nestbox in a transition cage. The dormice are fed for a few weeks until they move out into the wood which is coppiced on a 7 year rotation. It takes 3 years for newly coppiced hazel to produce the nuts which dormice eat after nibbling a neat round hole in the shell. There are now 180 boxes at Treswell which are monitored monthly. Regular reintroductions from one of 600 other sites take place to maintain genetic diversity.

The nestboxes are like wooden bird boxes with a removable lid, but the holes (too small for most birds) are at the back. Woodmice too often move in and are evicted, but Lorna allows pygmy shrews to stay. The nests are a round ball of woven grass and leaves with a cosy tunnel to the middle where the female dormice live communally in the summer, in winter the dormice hibernate underground or in trees.


Treswell Wood is divided into sections and our team pushed through bramble and scrub to find the 20 boxes for monitoring in today’s section. When a box is sighted, silence prevails. One person tiptoes up to the box and inserts a duster bung to contain the occupants. The nestbox is then removed from the tree and the nest gently probed for the presence of rodents. Yes, they do bite. If dormice are present they are gently contained in a large bag and individually bagged, examined for unusual characteristics such as a white tip to the tail, sexed, measured and weighed. Meticulous notes are made on the spot including the nature of the nest.

The dormice scampered away from the first two nestboxes, some running vertically up the tree trunk, others swinging like miniature monkeys through the brambles, clinging to creepers using their thick furry tail. One of the nestboxes contained a female with 6 sub-adults. The dormice have to be gently persuaded back into the nestbox which is replaced on the tree. Lastly the bung is removed and the search for the next nestbox begins. Our group were so lucky because a group in a different section did not find any dormice that day.

It only costs £5 a year to join the Nottinghamshire Dormouse Monitoring Group and members can take part in as many monthly monitoring sessions as they wish. Lorna has advised on Dormouse Conservation and re-introduction in the UK and abroad. She loves dormice (and pygmy shrews) and they are very lucky to have such a hard working and charismatic champion.

Marion Bryce

15 September 2019


%d bloggers like this: