After an unseasonably warm week, I wasn’t expecting to have to de-ice my car on this mid-October morning, but a sudden chill had hit. It finally felt like autumn! It turned into the most beautiful day of blue skies and bright sunshine but was still cold enough to see your breath - my favourite kind of weather. 

I was joining the Nottinghamshire Dormouse Group, a group of local volunteers founded in 2013 as part of the PTES Dormouse Reintroduction Project. They lead on monitoring the reintroduced hazel dormouse population on our nature reserves and the wider landscape. The checks I was about to get involved with are undertaken as part of the National Dormouse Monitoring Programme and with a recent report finding that dormice have undergone significant declines, the data we collect is used to inform dormouse conservation.  

I arrived at one of our ancient woodland reserves in the north of the county to find the group huddled together, where Lorna (Chair of the Nottinghamshire Dormouse Group, and NWT’s very own City Nature Recovery Officer) introduced herself and Michael (NWT’s Nature Recovery Manager and a member of the Dormouse Group) to any new volunteers. Some had come from as far as Staffordshire to join in on the fun!  

We spilt into three groups to cover the huge area we were about to check - which spanned three of our ancient woodland reserves. I was in Michael’s group, so we headed just over the road to find our first section. Michael explained that these are ancient broadleaf woodlands, and that like many woodlands in the UK they suffered large scale felling and replanting with non-native conifers in the 1950s. Since taking ownership of the reserves the majority of conifers have been removed and broadleaf trees once again dominate.  

I had visited once before in the spring to see the mesmerising flowers that these woodlands produce. Think floors carpeted in wood anemone and bluebells! It’s a must visit on your spring to do list. They are just as beautiful in the autumn though, with so many fungi to discover and in my case, get very excited about. 

We spotted these huge shaggy ink caps just off the path, and these bright turquoise fungi, which none of us had ever seen before. Looking it up in my fungi guide later, I found it to be green elf cup! 

We delved into the depths of the woodland from the main path (after missing the turning as we were too busy talking about the incredible history of the woodland). After a bit of searching, we came to our first dormouse box! 

The dormouse boxes are specially adapted and ‘bird proofed’ to make sure that they are primarily available for dormice to use. Rather than it being a circular entrance to the box, it is more of a slot, so that birds can’t squeeze in and take it for themselves (or at least not many species can).  

Dormice are a European Protected Species and are therefore protected by national and European legislation. The monitors in the group undergo years of training to get a dormouse licence, which is a legal requirement when interfering with dormice or their nests. When checking a box, first the opening is carefully blocked using a bung (a small cloth to prevent escape), then the top of the box slowly removed to peek and see if there is anything inside. If there is a nest present, we pop the box into a bag and open it up to see if anyone is home.  

Michael explained that the group only allow the use of their own colour coded bungs, rather than volunteers bringing their own. This is a precaution to make sure that they can keep track of them, and none are ever accidentally left in a box, stopping a dormouse from leaving. 

When identifying a nest, if it was a dormouse nest, there would likely be green leaves in there, as well as at times, a woven structure. Dormice will sometimes collect leaves straight from the tree, so a nest-box full of green leaves is usually a sign that a dormouse has been using the box. This is not always the case though as dormice will utilise whatever materials they can find in proximity to the nest-box to make their nests such as moss, grasses, fallen leaves, and stripped bark. Interestingly, they make nests all year round, for breeding as well as somewhere to sleep (some do a very nice job of it, others not so much!). 

If nothing immediately jumped out from the box, one of the volunteers had a gentle feel around the nest, to see if they could find anything. We had no luck in our first few boxes, but eventually we had three very springy dormice jump straight out once their box was placed in the bag. 

Each dormouse was gently scooped up and put into smaller bags, so that we could collect our data. As I held one of the bags, I was absolutely mesmerised by these adorable little creatures. After an initial jump around, they all seemed quite sleepy, and squinted at us, as if they were struggling to keep their eyes open! We were all very surprised at how lively they were with it being so cold (dormice can spend nearly three-quarters of the year ‘asleep’ in some form). 

They also tried to squish themselves up into corners of the bag to stay cozy. I was amazed at how warm they were as I could feel the heat radiating from their body - certainly much warmer than us on this freezing morning! 

We then weighed them, and gently handled them with gloves to find out the sex for our data. In our box of three, there was one chunkier male at about 22g (still only the weight of a teaspoon) and another smaller male and female. Michael explained that they could be related, or they could be complete strangers, they aren’t particularly territorial outside of the breeding season or picky about sharing their beds. It just means more warmth for them.  

We also recorded whether the individuals had white tipped tails, like the one pictured – an interesting genetic variation thought to be quite rare in the UK that many of our dormice appear to have. Currently the only scientific study into this variation was undertaken on Lithuanian dormice, so the group is carrying out their own research. Once we had collected our data, we then ‘posted them back into their boxes’ as Michael put it. Sometimes they took a little bit more encouraging to get fully back inside!

Our next box was an interesting one, containing a pygmy shrew! This one was too speedy to handle and absolutely tiny - I managed to snap this quick photo as it stayed still for a millisecond. 

We ventured through the trees looking for our next boxes, which was a challenge. I was surprised we managed to find our way as every direction started to look the same!  

Next, we came across a box containing four juveniles, that were probably only a month or so old, weighing a tiny 9g each. Unfortunately, their mother was nowhere to be seen - but Michael reassured us that they are at an age where they can just about fend for themselves. I was shocked at how young they were for their size, but amazingly, they can put on 2g a day if there is plenty of food around.  

Michael explained that despite using leaves in their nests, they don’t eat them as they can’t digest cellulose. When they come out of their nests in spring, they feed on woodland flowers and nectar, and when the flowers die off, they head up to the canopy of the woodland, feeding on invertebrates such as caterpillars. In the autumn, they will be eating lots of hazelnuts, seeds, and fruit to fatten them up before they go into hibernation.

I was surprised to learn that dormice often move about between boxes even after they have put the effort into building a nest. Usually, females don’t tend to travel as far from the nest as males. Michael told us about a female that had bred in one of our boxes, was then found hibernating just a few metres away, then back to the same box to breed for two years in a row. So, some aren’t massively adventurous! 

This October monitoring session was one of the last of the year, as most dormice will be hibernating from October to April, and they don’t use the boxes to hibernate. The temperature of the boxes will fluctuate too much for them in the winter, so they hibernate just above ground, where the ambient temperature is relatively stable. 

Since the majority of dormice we found weighed under 18g, this suggests that most of the dormice we found were likely to be this year’s juveniles, so a lot of the adults in our area must have already been hibernating. In total, the Nottinghamshire Dormouse Group recorded high numbers of dormice in all three of the reintroduction woodlands, 21 dormice in one, 28 in another, and a whopping 83 in the final reserve. The highest number ever recorded in our woodlands! Dormice have also dispersed into the wider landscape, so during the day we also checked a neighbouring woodland which is owned by a local landowner and recorded an additional 13 dormice. 

I left with many leaves and branches in my hair but had a great time and felt even better knowing that our population of dormice are doing so well, with record numbers!