Tag Archives: National Dormouse Monitoring Programme

Autumn dormousing

It’s been an amazing few months at my dormouse site, with lots of breeding and therefore lots of bouncy baby dormice to record.

August was a remarkable box check as we found nearly every stage of dormice (pinkies, greys whose eyes have not yet opened, greys with eyes open, older juveniles, adult testes scrotal males, adult females (lactating, pregnant)). This was great for the trainees who came out with me, who need experience of dormice at all these stages as part of their training. And it’s good to see little dormice!

Little dormouse

September was even more amazing. Out of 50 boxes, 9 contained dormice, but most of theses were young families, so in total we recorded over 40 individual dormice. I have never found that many on a box check before. For comparison, the most we saw on a single box check at my site last year was around 10.  As you can imagine, it takes quite a while to extract, weigh, sex and replace that many dormice, but no-one was complaining! It’s fantastic to see them do so well this year.

After the previous two months, I was expecting lots of activity on the October box check. In the end, it was comparatively quiet. We only found 4 (mostly this year’s young, dispersed from their maternal nests), plus one nest that was empty but warm. Hopefully that means that September’s young have all grown up and dispersed around the wood, concentrating on fattening up before winter. None of the ones we found were torpid (although perhaps some have gone into hibernation already).

Lovely dormouse

I was really encouraged to see a new nest in a box we haven’t previously found dormice in – it’s great that they seem to be using the whole site, not just a small pocket of it.

Of course not all the young dormice will make it through the winter, but hopefully the relatively mild autumn is giving them plenty of opportunity to fatten up and give themselves the best chance of waking up next April/May. We didn’t find any particularly fat dormice in October (unlike at one SDG site, where they found a 38g monster!), but they were all weights that mean I’m not too worried for their chances of survival.



Dormouse box check, July 2017

We had a fantastic dormouse box check at my site this month, finding six sleepy juveniles and an active adult.

Juveniles are this year’s young, aged at least 28 days and weighing more than 10g. Their fur isn’t as golden as an adult, but they are still super cute.

Sleepy dormouse
Sleepy dormouse

It’s really encouraging finding them this month, having not found any pregnant females or mothers with young last month – it shows they are breeding already, but using natural nest sites rather than dormice boxes. These youngsters have plenty of time to fatten up prior to hibernation.

I particularly enjoyed this box check as Dan, who’s a Surrey Dormouse Group trainee, working towards his licence, was in charge of the clipboard, directing the volunteers and recording data. This freed me up to actually check boxes for a change. There’s a delightful moment of suspense when you slide the lid of a dormouse box across and peak in; what will be in the box?

The dormice at my site continue to build rubbish nests. We never find textbook examples, with woven honeysuckle cores surrounded by green leaves. It’d be easy to dismiss many of the nests we find dormice in as apodemus nests or bird nests. This site has taught me to investigate any possible nest carefully.

Two sleepy juvenile dormice
Two sleepy juvenile dormice

We found two juveniles in what was little more than a pile of leaves. And there was a shallow, mossy nest, which didn’t look very dormousy, but I checked it anyway. On first exploration of the cavity and down the sides I could feel nothing. I was almost ready to conclude it was empty, but I went back to double check the cavity and ended up finding three dormice.

The check ended up taking quite a while, partly because we found quite a few dormice, and partly because those we did find weren’t in any hurry to get back into their nests. Several of the juveniles we found were awake but sleepy. One decided that halfway through climbing back into its nest was a good time to fall asleep. Another decided to leave its tail dangling out of the box for ages.

Dormouse refusing to put its tail back in the nest box
Dormouse refusing to put its tail back in the nest box

I’ve been checking dormouse boxes for seven years, but they can still surprise, entertain and delight me.

Dormouse activity in my site in 2016

I have been in partial hibernation this last couple of months, hence the lack of blog posts. But I have managed to do somethings, one of which is sift through my dormouse data from last year. I’ve made a little animation showing how dormice and other animals have used the boxes at my monitoring site over the last couple of years.


It’s great to see dormice making use of the boxes we put up in 2015. Hopefully it means this year they’ll start making use of the boxes we put up at the start of 2016.

Dormouse Box Check October 2016: dormouse activity in new areas of the site

After last month’s brilliant box check, I was hopeful that we’d see lots of dormice this month. I was expecting the seven youngsters we found in one box to now have separated and set up their own homes nearby. And I was hoping the pinkies would now be bigger and bouncier.

The first set of boxes we surveyed didn’t show new signs of dormouse activity. But, excitingly, there was the start of a new dormouse nest in one of this year’s boxes, in a new bit of the site. This box is one of four in a clump of hazel on the edge of the woods, and separated from the other boxes by a stretch of un-dormousey woodland – tall trees with little understory. It was a bit of an experiment putting the boxes here – I wanted to see if dormice would use this bit of hazel, given the unpromising habitat between it and the rest of the boxes. So far this year, nothing had used any of these boxes. So it was very exciting to see the start of a dormouse nest here.

The shrew who had taken over the bees nest which had taken over a dormouse nest has finally moved out – not before time – the nest was covered in shrew droppings, and sticky from the bees. The kind Dr C volunteered to clean that one out, which is great as it was a health hazard for any creature that might have ventured in.

There was no sign of any of last month’s young in the boxes near where we found the seven dormice. And the bitey adult male has moved out as well. But we did find a 16g young male in a wren’s nest. As I slid the box lid off, and the perspex over the nest, he clambered to the top of the mossy nest, pressing himself against the perspex. He turned out to be a lively little fellow, so I didn’t take a photo of him – I wanted to get him sexed, weighed and back in the nest before he had time to get too upset. This is the first time we’ve found a dormouse in that particular little section of the site, so more encouragement that they’re not limited to one bit of it. And it’s good that he’s probably big enough already to get through the winter.

No sign of last month’s pinkies – hopefully mum has made a nice natural nest for them.

I’m not sure if that’s the last box check I’ll do this year – if the weather stays mild and there’s still food about, dormice could still be active in a month’s time (particularly this year’s young, as they work on fattening up). But if the weather turns cold, we may not find anything. I’d be a bit sad, if that’s the last check of the year, but, sitting beside my first fire of the season, maybe it is time for hibernation.

Apart from the one dormouse, and signs of new nest building, the other thing of note that we found was this rather fine caterpillar.  Possibly a pale tussock? What do you think?

Catepillar - possibly a pale tussock?
Caterpillar – possibly a pale tussock?

Dormouse box check September 2016: lifting Sophie’s curse

I was very excited about this month’s dormouse box check, after the promising signs last month, finding a pregnant dormouse and a young family. I was expecting to find boxes of bouncy young dormice, ready to explode out like jack-in-the-boxes as soon as the lid was removed. But I had forgotten that Sophie, one of the volunteers joining me this month, seems to be cursed, with dormice hiding away from boxes whenever she visits a site, no matter how many dormice are usually found there…

I was reminded of Sophie’s curse early on in the check, when the nest that held the pregnant female last month turned out to be empty, and none of the surrounding boxes had any sign of dormice. Hopefully that means she’s made a natural nest somewhere to have her babies, and we may see them turn up in our boxes next month. But it doesn’t help Sophie get the experience of handling young dormice that she needs to get her license. Still, we knew that one of the last boxes of the check had a family in last month, so we continued with some (slightly diminished) optimism.

The woods are starting to feel autumnal, with the leaves just starting to turn yellow, and fungi everywhere you look.


Luckily we didn’t have to wait until the end of the check to find dormice. A new nest had appeared in a box about halfway through our check route, so we got it off the tree, and had a proper look in. There seemed to be three or four young (eyes open) dormice in the nest. So Sophie started bagging them up for weighing. But it didn’t stop at four. They just kept coming. Five… six… seven. No sign of an adult, but seven healthy, lively youngsters. I’ve no idea how they all fitted in the nest.

Dormice generally have litters of about four, so seven is a big, but not unheard of, number. Most of them were around 8-10g, although one was an impressive 14g (he was also quite feisty, biting Sophie – quite unusual for a dormouse, but perhaps his feisty attitude is how he got so much bigger than his siblings). We used coloured twisty tags to help us keep track of which was which.

We were able to sex a few of them – mostly males, but my personal favourite was a very pretty female with a white tip to her tail. Hopefully, with that distinguishing feature we’ll be able to spot her again next month, and see how she’s doing putting on weight for hibernation.

Young dormouse
Young dormouse

With seven dormice to go around, we all got a chance to handle a few while putting them back in the box. They were very cooperative, with none trying to escape the nest while we posted their siblings back in. Just as well, as we could have been there all day otherwise…

A few boxes later we found an adult male (who also bit Sophie). By that time we were wondering if she smelt of hazelnut…

A shrew has taken over one of the old bees nests, which they’d taken over from a dormouse nest… It’s funny how some boxes seem to be attractive to several different species, while other nearby boxes are empty.

Our last box of the day also revealed good news – a lactating female, with tiny pinkies (the official term for dormice babies before they develop fur – these were less than 15mm long). We didn’t get them out of the box, and processed mum as quickly as we could (although not before she had bitten me, through the bag!).

With 9 dormice plus pinkies we have well and truly lifted Sophie’s curse. Let’s hope they have a good month feeding, putting on enough weight to see them through the winter… (now there’s an idea!)


Dormouse box check, August 16

As we assembled for this month’s box check I was in two minds about whether to go ahead with it. It was raining, which isn’t ideal, as you don’t want any disturbed dormice getting soggy (their fur isn’t waterproof). And it was quite windy in the car park on top of the ridge of the North Downs. The forecast said it should just be a shower. But the wind was due to double by lunchtime. It’s just not sensible to be in the woods on a windy day.

But the volunteers had travelled to get there (giving up a precious Saturday lie-in). And I would struggle to find time for the check another day this month.

In the end I decided to see what it was like at the site (a 15 minute walk away from the car park, and a bit more sheltered), trusting that the forecast would be right about the shower, and that we’d finish the check before the wind picked up.

Once in the wood, the wind became less noticeable. The leaves were rustling, but the branches were still. So at least it was safe for the volunteers.

We started, as always, with nine boxes we put up last year across the path from the rest. It was where we had found a dormouse last month, so a promising place to start. The dormouse had moved on from last month’s nest. But, a few boxes later, we hit gold.

A lively dormouse jumped out of the box. Once we had bagged it up, it was clear that he was a male in breeding condition. It’s usually quite hard to determine the sex of a dormouse, but that wasn’t a problem with this fellow. While he was safe and dry in a weighing bag I explored the nest for any other occupants, and found a beautiful pregnant female. This was fantastic news – it’s great to see breeding happening on that side of the path. Both dormice safely returned to their nest, we carried on.

Last month we had a couple of bees nests in dormouse boxes. We approached them with caution, watching and listening for any signs of bees. They seemed to have left the first nest, and, as we watched, a shrew emerged from the second. I’m guessing that one no longer has bees in. But we’ll wait til next month to clean it out, to be on the safe side (the bees seem to enjoy lulling you into a false sense of security at my site).

As the check progressed the rain eased up, although by that time most of us had soggy feet.

Dr C checked the last box. Last month it had an empty bluetit nest in it. If it was still disused this month, we’d clean it out, like we had with the other manky bluetit nests. As he slid the lid across, we saw it had been transformed in the last month. No longer a shallow open nest, the box was full of moss (like a wren’s nest), with leaves and honeysuckle bark as well. Although not a classic dormouse nest, we were both suspecting dormice, when a golden face appeared against the perspex.

Dan, a volunteer who is working towards his license, had the job of bagging the dormouse, who turned out to be a lactating mother. In the nest cavity we could feel some young, but, given the less than ideal weather, and their vulnerability, we decided to leave them in the warmth and safety of the nest, and return mum to them as quickly as possible.

Mummy dormouse

It was a wonderful end to the check, and I am very excited to see how they are all getting on next month.

July 2016 Dormouse Box Check

July’s dormouse box check got off to a good start. As I looked into my first box of the day, a lively dormouse appeared.

By the time I had got the box off the tree, into the bag, the dormouse had turned shy, burrowing beneath the nest. The nest itself wasn’t particularly well constructed, so unlikely to survive being lifted out of the box.

An unusually messy, loose dormouse nest
An unusually messy, loose dormouse nest

Often when active dormice are reluctant to come out of their nests at this time of the year, it’s because they have young they want to protect. So I took things slowly and carefully. Once I had established there were no youngsters in the nest, I had another go at getting out the adult, this time successfully.

I finally extracted the dormouse from it's box
I finally extracted the dormouse from it’s box

It’s always a little nerve-wracking, handling your first active dormouse of the year. The last active one I handled was back in October – 9 months ago. Luckily this one was pretty cooperative (and pretty) so didn’t make a run for freedom up my arms.

We weighed and sexed her quickly, then returned her to the box. She was 16g, which is not unusual for the time of year.

The dormouse in a bag, to be weighed
The dormouse in a bag, to be weighed

The rest of the check was less exciting – no other dormice and no new dormouse nests. The bees are still occupying a couple of former dormouse nests. The bluetits have all left their nests, but a couple of wrens were still nesting in the cosiest nests imaginable.

The pleasant morning was completed by a quick lap of a Cherry Fair (it’d be rude not to buy some cherries).

Hopefully next month we’ll have some signs of breeding to boost the local dormouse population.

Dormouse box check: June 16

This month’s dormouse box check started early with just Dr C and me. The birds nests were all empty, with the chicks having hatched and fledged between checks. The bees were still occupying a couple of dormouse nests, so we gave them a wide berth. And no dormice to be seen. There wasn’t even any sign of new nesting activities.

So a quiet check. Even the woods seemed relatively subdued after the cacophony of wildflowers on display last month. It was the first check this year without finding any dormice. But a pleasant way to spend a few hours, and good to get a chance to check boxes myself, rather than just map read and supervise. Hopefully next month we will find some dormice, and maybe even some youngsters.

What I found at my dormouse site in 2015

I have been meaning for ages to look at how dormice, woodmice and birds used different parts of my site over the course of last year. The burst of energy that spring gives me, and being relatively on top of the gardening, meant I had time on Sunday to play with presenting my data visually. I’ve made a short video to show which boxes were used by what, when.

As you can see, birds dominated the site for the first few months. But quite a few bird nests were subsequently taken over by dormice, once the birds had finished with them. By the end of the year there were an encouraging number of boxes with dormouse nests in.
What do you think of this way of showing the data? What strikes you from it?

It’ll be interesting to look at this year and last year side by side.

Dormouse box check April 2016: cold and wet

One of the advantages of surveying for dormice is that usually the weather’s pretty good. Dormice hibernate all winter, so we don’t check the boxes during the coldest months. And dormice don’t have very waterproof fur, so we don’t tend to check when it’s chucking down with rain, to avoid them getting cold and wet if they get disturbed by us and run up a tree. So yesterday’s check was unusual in its unpleasantness.

The forecast had said that yesterday would be dry and cloudy. The first drops of light rain were falling as we gathered at the meeting point. But not enough to make me think twice about checking – usually the trees provide some cover , so you hardly notice light rain once you’re in the woods.

It’s a bit of a stroll from the meeting point to the start of the site. As we walked, the rain didn’t ease off, but still wasn’t enough to make me consider turning back. As we checked the first ten boxes, the rain got heavier, but we’d come that far already, were armed with an umbrella (for the dormice, not for us – have you tried walking through a wood with a brolly?), and it was cold enough that I was expecting any dormice we found to be torpid, so unlikely to dash up a tree at our approach. I decided that we should continue.

Now the site has 50 boxes up, surveys take a bit longer than usual. We got wetter, and colder, and more dispirited as we went. For the first 25 boxes we found nothing apart from the start of a few bird nests. About halfway through we found a common shrew, which was a brief moment of excitement, but given the weather we didn’t want to disturb it more than necessary, so we moved swiftly on.

Then we got to the few dormice nests we’d left in the boxes from last year. To check them properly we took them off the trees, and, with one person holding a brolly over the bag, someone else had to strip off coats and jumpers to have bare arms for checking the nest (dormice are excellent climbers, and clothing makes it too easy for them to run up an arm). The first nest was empty, but in good condition. The next, where we’d found a dormouse last month, look like it had been flattened by a mouse jumping up and down on it like a trampoline. Nothing in that box.

It wasn’t until we’d got to our 46th box that we finally struck gold. A torpid 16g male dormouse in one of last year’s nests. By that time the rain had almost stopped, and suddenly the whole soggy check seemed worthwhile. If you’ve ever seen any of the ‘making of’ bits at the end of BBC wildlife documentaries, you’ll know that a lot of wildlife watching is about perseverance in the face of uncomfortable conditions. I felt like the team of volunteers who carried out the check yesterday really earned seeing that dormouse. We collected the necessary data as quickly as possible, and tucked the dormouse back up in his nest.

I didn’t take any photos of the check (it wasn’t right weather or light for it), so you’ll have to make do with a photo of last month’s dormouse instead.

Torpid dormouse
Torpid dormouse

My dusters and bag have just about dried out now, and I was very glad of a hot drink and change of clothing when I got home. I woke this morning to glorious sunshine – I picked the wrong day for the box check this month! I must confess, when I heard that the box check this morning at a nearby site had found no dormice, I felt slightly better about my choice of days.