Tag Archives: Surrey Dormouse Group

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.


Surrey Dormouse Group trip to British Wildlife Centre

Winter is a quiet period for dormousers. The dormice are hibernating, so we wash our dusters, enter our data onto the national database, and put our feet up. Here in Surrey we’ve not quite been hibernating – 30 of us met up at the British Wildlife Centre for a meeting to celebrate our achievements from last year, and discuss plans for 2016. And, of course, to see the wonderful collection of animals they have there.

It’s always good to have an excuse to visit the British Wildlife Centre. The runaway show stealers for me were the otters (as always). It wasn’t great weather for photography (very little light), but here are a few of the more acceptable snaps I took.

Red Squirrel
Red Squirrel
Red squirrel looking into a camera lens (shame the lens cap was on!)
Red squirrel looking into a camera lens (shame the lens cap was on!)

How was 2014 for dormice in Surrey?

This article is adapted from one that I wrote for the spring/summer issue of the Surrey Dormouse Group (SDG) newsletter, and is reproduced here with their kind permission. It's based on data collected by dozens of volunteers across the county. If you would like to find out more about the work of SDG, visit their website

Last year SDG members checked a total of 7076 boxes from 18 sites. Data from each SDG box check gets reported to the National Dormouse Monitoring Programme, to feed into their national analyses – you can read about how 2014 was for dormice nationally in the Dormouse Monitor.  Here’s a summary of the data from Surrey.

How many dormice?

We saw a total of 487 dormice over 2014. That works out at a mean average of 3 dormice per 50 boxes checked, but there was quite a range of numbers seen at box checks: from 0 per 50 boxes to 27 per 50 boxes. At a third of box checks no dormice were found. The median number of dormice found per 50 boxes checked was 1, which is probably a representative average, given that a few large numbers are skewing the mean. Some sites that had quiet starts to the season saw large numbers later on. On average, we also found 2 empty dormouse nests per 50 boxes (ranging from 0 to 18).

Number of dormouse found per 50 boxes checked, Surrey, 2014
Number of dormouse found per 50 boxes checked, Surrey, 2014

When did we see them?

The earliest dormouse was a 20g torpid male, found on the 6th March, and the latest ones were 3 found at the beginning of December (that’s not to say others weren’t around earlier or later – just we weren’t checking so didn’t find them). As you can see from the graph above, average numbers were highest in August to October, and lowest in March and April.

How much did they weigh?

Females weighed slightly more on average than males (19g vs 18.7g), but this changed considerably over the course of the year, as you can see from the graph, with weights at their highest just before hibernation. The heaviest dormouse recorded was a 33g female found in October.

Average weight of dormouse found in Surrey, 2014
Average weight of dormouse found in Surrey, 2014

Other interesting features

Dormice with white tail tips were reported 36 times over the year, including a family of juveniles, all with white tail tips. There were 9 dormice with stubby tails.


The earliest pinkies were found on 20th July. (Pinky is a technical term describing baby dormice before they grow fur). On that same box check the earliest greys (babies that have their first coat of fur, which is much greyer than an adult) were also found. The latest pinkies were found on 25th September, and the latest greys were found on 20th October. Dormice born later in the year have more of a struggle to fatten up in time for hibernation, but those born too early in the year may struggle with their mother not being able to find enough food for herself.

The largest number of dormice found in one box was 8 (mother with young): boxes with 8 dormice were found at two sites.

Other box occupants

Apart from birds (which seem to take over a large number of boxes in spring at some sites) and invertebrates, the most common other occupant were wood mice (162 were seen, 21 of which were found in dormice nests) and yellow necked mice (29 were seen, only one of which was in a dormouse nest). There were also 12 unidentified apodemus mice (wood mice or yellow-necked mice). The rarest other box occupant was the pigmy shrew, with only 7 reported over the whole year (2 of which were in one box).

Dormice! Bouncy baby dormice!

Please excuse the excessive exclamation marks in the title of this post. I am just rather excited about the dormouse box check at my site this month. Having only found one dormouse at my site so far this year (and even that was months ago), this month we found a whole family of healthy, lively dormice.

I think word must have got round Surrey Dormouse Group that my site isn’t the best bet for seeing dormice, as my only ‘volunteer’ this month was the wonderful Dr C. I think he brings me good luck with dormice, as we found the previous dormouse on a check when he was my only helper. Anyway, hopefully now we’ve got a few more dormice at the site, we’ll have more regular success so volunteers can get some dormouse handling practice.

The occupied box had a lactating mother with three lively, eyes open young. It won’t be long before they will be able to leave the nest and live independently (hopefully in some of our nest boxes).

Bouncy dormice
Bouncy dormice

Dr C saw the mother’s nose peer out of the nest when he was checking the box. It’s the time of year when dormice are busy having babies, so we knew that there was a real possibility that there may be young in the nest. That was quickly confirmed – as soon as we had put the box in the rubble sack and taken off the lid, the bag was full of four dormice dashing round at incredible speed. Having so far only handled one, torpid, dormouse this year, trying to safely catch and bag each of them was an intimidating prospect at first. But, after taking a deep breath and picking a target, I got the first one, and it got easier from there.

Young dormice are harder to handle than adults – there’s less to get hold of,  and their paws seem stickier, allowing them to climb arms more easily (something you have to keep an eye on when you’re dealing with several at once – you don’t want any escaping up your arm while you try to catch a different one).

After catching, weighing and sexing each mouse we put them carefully back into the nest. Not all of them seemed very keen on going back in, but once in they stayed there.

There’s plenty of food around, so they should have time to gain enough weight to hibernate through the winter. And they all looked in good condition.

Apart from delight at seeing lovely dormice, this new find is also really encouraging as the nest was in a different part of the wood to where we’ve found the other dormice nests.  We also found another new (unoccupied) nest in another part of the site. At some sites you find most of the activity in a relatively small area, but, from this first year of monitoring, it looks like they’re present across most of the monitoring site. While four dormice (one family) isn’t a huge number compared to some other sites, it’s the highest we have had so far, and I am encouraged by it.

Dormouse ecology (or how I got back into wildlife)

I’ve always loved wildlife, and being out in nature. But during my first few years of adult life, as a student living in big towns, I didn’t really act on that love. I’d go for country walks, and spend my holidays back in the beauty of Devon. I was always pleased to see exciting wildlife, like birds of prey, reptiles or even just bunny rabbits. But that was as far as it went.

Then, in 2006, newly married and living in the outskirts of London, it all changed. I had signed up to become a member of my local wildlife trust. One day their ‘what’s on’ brochure landed on my doormat, and, lured by a cute picture, I signed up for a one-day dormouse ecology course (the first of many courses I’ve done, and the beginning of a love affair with dormice).

Why do a dormouse ecology course

torpid dormouse
Torpid dormouse

My reasons for doing the course were pretty feeble – I knew practically nothing about dormice, apart from how cute they looked. I thought it would be an interesting way of spending a day off. That’s about it.

I was right. It was an interesting way to spend a day off. I did get to see lots of cute pictures of dormice. I even got a go at handling a couple. And I had my first experience of checking dormouse boxes.

One of the things that really struck me from the course (apart from how adorable dormice are) was that normal people, like me, could help with wildlife conservation. That there was still so much scientists don’t know about British animals, and that amateurs could help to fill those gaps. That was a bit of a revelation for me.

Dormice are fascinating creatures (as well as being undeniably sweet). They’re arboreal and nocturnal, so you’re not likely to bump into them, and they are rare in the UK. Add to that the fact that they spend several months a year hibernating – you could easily live within a few metres of a dormice and never see one.

There are other, more practical reasons for doing a dormouse ecology course, besides curiosity and liking cute pictures. Dormice are protected by law, meaning you need a licence to disturb them in any way. Doing a dormouse ecology course is an essential step towards getting your license, so is useful for professional ecologists and keen volunteers who want to contribute to dormouse monitoring.

Surrey Dormouse Group Ecology Course: 22 August 2015

Surrey Dormouse Group are running a dormouse ecology course on 22 August in Guildford. It’s a full day with classroom work in the morning, followed by a box check in the afternoon. There will be a charge for the day and you’ll need to bring lunch. It does not include dormouse handling, this is a separate course, but hopefully should include seeing dormice during the box check. You will receive a certificate of attendance at the end of the afternoon. There are only 20 places on the course, going fast, so if you would like to find out more, or would like a registration form, please email info@surreydormousegroup.org.uk for full details.

The course will be led by David Williams, a dormouse expert with years of practical experience, and the man who first introduced me to the delights of these beautiful animals.

The dormouse course I did, almost ten years ago, was the start of me getting serious about wildlife – realising how much there is to learn, and that I could get involved with studying and protecting it. Who knows, this year’s course may be the start (or another step towards) something special for you.

Dormouse box cleaning at my new site

I woke up really early on Saturday, I was so excited about checking and cleaning the dormouse boxes at my new site. It’s the first box check I’ve done since getting my licence at the end of last year, and the first one I’ve led.  And I don’t know the site that well.

I dreamt that we found a box with five placid, fat dormice. Sadly reality didn’t quite live up to this – all the dormice at my site seem to be hibernating still. (Elsewhere in Surrey one of my fellow dormousers found three, including a chubby 25g male – that’s a good pre-hibernation weight, let alone for one just emerging from hibernation!) But we did find one common shrew, which we quickly let go to find its next meal.

Our main task was to get rid of the manky old nests from boxes, with lots of woodmice or bird droppings, so they’re fresh and clean for when the dormice are active. No signs of any new bird or dormouse nests yet. I was pleased that we were able to find all the boxes – the map I’ve inherited is clear and accurate, which always helps.

In addition to the spring cleaning we had 10 new nest boxes to put up. Luckily I had the assistance of some very helpful volunteers, so we got through all the work in a reasonable time. We managed to find some likely looking hazel stands to put them up on just across the track from the other boxes, so with any luck we will be able to find them again next month. And if we find any dormice in them, we’ll be able to feel a quiet glow of satisfaction that we helped provide the basis of a good home for them.


Dormouse license!

After four years of volunteering at box checks, scrambling over and under fallen trees, battling holly and brambles, and being stung by nettles and bees, I now have my dormouse license! Dormice are a protected species in the UK (as there are so few of them), so to do anything that may disturb them you need a license from Natural England. To get the license you need to prove that you are capable of handling dormice safely, and have considerable experience of doing so under the supervision of license holders.

When I started volunteering at box checks I didn’t really have ambitions to be a license holder – it was just a pleasant way of spending a Saturday morning, and seeing adorable little animals. But I kinda got hooked, and Surrey Dormouse Group supported to pursue my interest further. At the time they were running an excellent training scheme, having clear requirements for what I needed to have experience of before putting in for my license. This included courses of dormice ecology, surveying and handling. I needed to know how to do a nut hunt, maintain nest boxes (a bit of DIY), set up a new site, record data, use a map to find boxes, give directions to volunteers, deal with other box occupants (like woodmice, birds, bees and shrews), and of course handle dormice at all stages of development.

Hazel dormouse

By Björn Schulz (= User Bjoernschulz on de.wikipedia) (selbst fotografiert von Björn Schulz) [GFDL, CC-BY-SA-3.0 or CC BY-SA 2.5-2.0-1.0], via Wikimedia Commons

It’s taken me a while to build up the necessary experience (mainly because the sites I usually volunteer at don’t have many dormice). As part of my training I’ve had the privilege of learning from many experienced license holders, as well as other volunteers with wide-ranging knowledge of nature.

Torpid dormouse
Dormouse found during regular monitoring by Surrey Dormouse Group

I’ve been on checks where it’s so cold my fingers have got too numb to undo the wire catches to the boxes, and others in the steaming heat of summer. I’ve had a few war wounds (bee stings, nettle stings, and been bitten by a dormouse – quite a rare occurance) and tripped over once or twice. I’ve seen many bluetit nests with chicks, and dormice from tiny pinkies to obese adults ready for hibernation. I’ve also witnessed a few tragedies – the dormouse who shed its tail (like lizards they can do that if they’re stressed), and nests of dead chicks or dormice. But overall the experience has been a joy –  even if we don’t find any dormice on a check, it’s a pleasant way of spending the morning. And having a torpid dormouse snuggle up to your thumb is just adorable…

So, now I’ve got my license, what does that mean? Sadly it doesn’t allow me to hibernate all winter (my employer would have something to say about that…). It does mean I can lead box checks. I’m hoping to get a site of my own to run next year, but if not I will help out when other site leaders in Surrey Dormouse Group can’t do a monthly check. It’s a big responsibility, looking after the wellbeing of those lovely little mice, but I think it will be rewarding.


Related posts

Review of the dormousing year

It’s late November, and despite the usually mild weather, most dormice will be hibernating by now. That gives dormouse monitors some time to take stock of the year, enter data onto the national database, and start planning for next year.

This week I attended a meeting of Surrey Dormouse Group site leaders. It was the first I’ve attended, as I have only just finished my traineeship. It was very interesting to hear about all the different monitoring sites in Surrey – I hadn’t realised how many there were. But then Surrey is the most wooded county in England, and has some good dormouse habitat.

The consensus seemed to be that 2014 wasn’t a great year for dormice in Surrey (with the exception of a couple of very popular sites). This matches my own experiences this year, where several checks I did resulted in no dormice. Some sites had good numbers at the beginning of the season, and then some quiet months. Other sites saw very little until October.

There are many puzzles in dormouse monitoring. Several of the sites adjoin, or are well connected to each other. But there seems to be little link between how well they do in terms of dormice numbers. A couple of sites have big problems with squirrels destroying the dormouse boxes, while in adjacent sites this isn’t an issue.

I’m hoping to get my own site next year, which would be exciting. The group discussed a few possibilities for developing or revamping sites. The main limitation is lack of funding. It costs around £10 to make a dormouse box, and a new monitoring site needs 50, which adds up. We’re going to try to raise some money to allow us to set up new sites, as the data monitoring provides is essential to protect dormice.

Another plan we discussed was doing some habitat work (coppicing trees) to help dormice thrive in our existing sites.

Exciting stuff for the winter, although I suspect the dormice have an even better way of spending the cold months.

Dormice don’t read text books

One of the things I love about monitoring dormice is the way they frequently surprise me. When I first started learning about dormice I was amazed at how much we don’t know about them. Through projects like the National Dormouse Monitoring Programme we’re learning all the time, and it’s great to be able to contribute to this research. Sometimes I think they deliberately set out to prove the textbooks (and me) wrong.

Although October is usually a good month for dormouse monitoring, I wasn’t expecting to see any at the site I helped with this month. No dormice were found in the previous few checks. I was prepared for a pleasant but mouseless scramble round the woods.

I was very happy to be proven wrong. We found six dormice, all of decent weights (although none were very chubby). For some reason, they were all in pairs this time. Dormice aren’t supposed to be social animals, at least when they’re adult and not-breeding. We had a box with a male and a female, and two boxes with two females in. All adults. It’s not like there weren’t plenty of other empty boxes to choose from, if they’d wanted some peace and quiet.

Another thing dormice are supposed to not do is take food into their boxes. Unlike woodmice who cache nuts, dormice tend to eat outside where they find the food. Once again the contrary mice were intent on proving the experts wrong, as we found a nut nibbled by a dormouse in an otherwise empty box. The nibbled nut had since been taken over by a spider.

Apart from the dormice it was a quiet box check. No wood mice, yellow-necked mice or shrews, and of course the birds finished nesting a long time ago.

That may well be my last check for the year, depending on how cold it gets over the next month. The dormice will soon start constructing their hibernation nests, down on the woodland floor (or at least if they’re following the advice of the text books they will). Time for me to start working on something similar?

Dormouse box cleaning

It was lovely to get back to the woods this weekend for my first dormouse session of the year. Box checks naturally come to a halt over winter (an advantage of monitoring an animal that hibernates), so it has been a few months since I last helped at a check.
Most dormice are still hibernating in March, so the focus of Saturday’s session was to clean and repair the boxes, ready for when the dormice emerge. We were a bit worried that we may have left it too late this year, with the warm weather meaning spring seems to be springing earlier than usual. But we didn’t find any dormice, and not many birds have started nesting in the boxes either.
We had a lovely day for it. Quite a contrast to most of the box cleaning sessions that I have done, where my hands become numb from cold within the first few minutes.
While we didn’t find any dormice, there were quite a few wood mice that had to be evicted from the dormice boxes.
Orchids and bluebells have already come up (although not in flower yet),  while primroses and violets were blooming. I was expecting more trees to have come down in the storms, but not many appear to have been damaged,  at least in the parts of the wood we monitor.
Anyway, the boxes are now clean and ready for dormice to occupy. The next check should be exciting.