Bat and dormouse quest

posted in: Cornwall Wildlife Groups | 1

Our bat and dormouse survey day marked a quarter of a century anniversary of bat checks at Armstrong’s Wood for our resident local ‘batman’, Tony Atkinson. We were jointly led by another very good friend of our local wildlife, Jen Bousfield, who is both qualified and experienced in Hazel Dormouse surveys, and was standing in as dormouse monitor for the site.

Armstrong's Wood view to River Inny
View down to the river Inny from the path through Armstrong’s Wood nature reserve
Reserve sign, Armstrong's Wood
Information about the nature reserve provided by Cornwall Wildlife Trust

Since 1994 (25 years ago!), October has been survey time in Armstrong’s Wood Nature Reserve for Tony. While he inspects the bat boxes, often high up on ladders, the dormouse monitor and assistants do the same – a little nearer the ground – for the dormouse boxes around the wood.

These surveys draw quite a following from local wildlife enthusiasts, especially from LAPWG, the Launceston Area Parish Wildlife Group, who made up the vast majority of the participants. Among the other onlookers were an environmental consultant who is also a trainee bat inspector, ready to take accurate notes of the bats found and the box numbers, and some people who had found the event on the internet and were glad to have done so.

Tony examines bat box
Tony examines a bat box above the river

Tony has the assistance of volunteers who help carry the ladder, torches and new bat boxes and lids. Jen was assisted by helpful countryside ranger Jenny Heskett, who is also licensed to inspect dormouse boxes. Today there was a wide age range of volunteers and assistants. Equipment also varied, from Tony’s enormous torch to the bright LED lights in the mobile phones of much younger potential bat watchers.

Checking for bats with mobile phone lights
Checking for bats with mobile phone lights
Assistants and onlookers
A few of the assistants and onlookers

Today, Sunday 13th October 2019, we were extremely lucky with the weather. I had already been soaked through by a downpour in the morning, and a large puddle had formed on the floor under my other raincoat, hanging up to dry back at home. Fortunately, the forecast was very good for the afternoon as the rain pushed eastwards, and we had a fine afternoon with glorious sunshine showcasing the autumn beauty of our leafy part of Cornwall.

Glorious sunshine & Tony up ladder
Glorious sunshine

I was giving a lift to my good friend Jenny, the countryside ranger. I parked the car deep in a thicket of nettles on the verge of the quite narrow road near the nature reserve, at the bottom of a line of tightly parked cars. The verge was quite solid, and I have a handy extra low gear, should I need it for extracting us from the mud and vegetation. Jenny clambered nimbly across from the passenger seat and out of the driver’s door, and we were greeted by Jen’s husband Pete, who was checking that we all went to the right place. Armstrong’s Wood is lovely, but it is not suited to being a ‘showcase reserve’, which would have a generous car park and an obvious entrance. In fact, it is only accessible by arrangement with the Trust.

Intro by Tony Atkinson
An introduction by our own ‘batman’, Tony Atkinson
Gathering before the quest
Ready to start out on the quest

Most of the assembled bat and dormouse enthusiasts were already mingling under a gazebo and after the final couple arrived, Tony gave us an introduction. He explained that checks now take place every October and May, times when the inhabitants of the boxes will be disturbed the least. At first, only the traditional wooden bat boxes were placed on trees in the wood, but then five years ago, he installed four new boxes in the style of a beehive, with narrow slots for the bats between insulating foam layers. These boxes don’t have traditional opening parts and are completely open at the bottom. The bats fly in from the underneath, crawl up into the warm, and can be viewed from below using a torch. Three of these new-style boxes were colonised very quickly, while wooden box occupancy went down. In August this year there had been over 100 Soprano Pipistrelles in one of them, plus two Noctules. A couple of years ago there were over 200 breeding Sopranos in the same box during the summer, however. Tony was sure that these weren’t Common Pipistrelles, thanks to bat detector evidence.

Gathering up the equipment for the bat survey
At the start
Jen (left, by Land Rover) is our dormouse expert, newsletter writer and chief organiser as well as being one of the LAPWG members who provide fantastic refreshments.

The usually golden-brown Noctule has a quite snub-nosed appearance, like a pipistrelle, but is a bigger animal – apparently six times larger than a pipistrelle. It is also a UK BAP Priority species, usually found in woodland.

Noctule in box © Tony Atkinson
A Noctule bat in a wooden box photographed at Armstrong’s Wood. Photo © Tony Atkinson

Tony went on to say that the wooden boxes were being retained because they give trainees handling experience of wild bats. Most who wish to gain the obligatory qualifications needed to inspect bat sites and handle bats go to bat rescue centres, where the bats can be handled and studied. However, this is not ideal, as the rescued bats get used to being handled and therefore behave differently to bats in the wild.  

Back in 2007, I went on the October bat check in Armstrong’s Wood and was delighted to be able to see and photograph a group of Brown Long-eared bats in one of the wooden boxes.

Brown long-eared bats in wooden box 2007
Brown long-eared bats in a wooden box, Armstrong’s Wood, 2007

Sadly, the dormice of Armstrong’s Wood are becoming “more elusive than ever,” these days, although one occupied box with a dormouse nest was found last year.

Sleepy Hazel Dormouse. Photo © Jen Bousfield
Here’s one that licensed dormouse monitor Steve found on an earlier date (never handle dormice without a proper licence).
Photo © Jen Bousfield

It seemed that if we wanted to see either bats or dormice, bats would be a better bet. Tony gave us the necessary health and safety advice about the reserve, and we headed off along the rosehip-lined field edge, some of us reminiscing about the lovely and diverse flowers, including orchids, that had seen there back in May.

It’s a good year for berries (these are on a holly bush)

We weren’t far in before we came across the first insulated box. We had to take turns to look up vertically. On this occasion, no one seemed to be in.

Insulated bat box
Our first insulated bat box
Using a torch to see bats
The insulated bat boxes are viewed from below with a torch

Continuing onwards, we came to the first of the wooden boxes. At this point we hadn’t quite reached the dormouse boxes, and so the whole group was still in one place.

Carrying ladder
Carrying the heavy ladder around the nature reserve

We watched Tony almost sprint up the ladder (how old is he? Nature is obviously very good for the constitution).

Bat box inspection
Box inspection by Tony

We couldn’t imagine Tony agreeing to the rigmarole of attaching safety ropes and harnesses around himself and the trees … but we were comforted by the fact that he knows what he is doing, and that there was at least one strong man steadying the ladder from the bottom, as well as helping ensure that it was firmly in place before our expert ascended.

Foam box AWE contained two pipistrelle bats. Their gingerish hue led Tony to pronounce them as probably Soprano Pipistrelles, which Tony has found to be more ginger in colour than Common Pipistrelles.

2 soprano pipistrelles in box
We spotted two soprano pipistrelles in an insulated box, their faces reminding me of Pekingese dogs
A much clearer photo showing the incredible bat capacity of the insulated boxes at Armstrong’s Wood. Photo © Tony Atkinson

Rather than being a gangster bat, as in the popular US TV crime series The Sopranos, the Soprano Pipistrelle is of course named for its voice. Its echolocation call (bouncing sound off insect prey to find their position in the dark) is at its peak at around 55kHz, whereas the notes of the common pipistrelle are at their strongest a little lower down, around 45kHz. I would describe the sound of a pipistrelle on a bat detector as bubbling and chirruping – certainly the most common call to hear around buildings such as our house.

All the wooden boxes turned out to be devoid of bats. This was a shame, given Tony’s daredevil ladder-climbing and box-opening feats and the efforts of his helpers carrying and erecting the heavy ladder for two hours. Nevertheless, records of no bats being present are statistically valuable too, and help give us an indication of trends in bat numbers, roosting preferences and behaviour. Perhaps the success of the insulated boxes has drawn the bats away from the wooden ones.

Another foam-filled newer style of box revealed another eleven Soprano Pipistrelles in a long line. While those of us not involved with ladders and torches watched Tony inspect boxes, we also kept an eye on the ground, looking for nuts that had been nibbled by dormice. Sadly, we didn’t find any. I did find plenty of holes in the ground. I guess the one pictured must have been excavated by a Bank Vole.

Hole in the bank
Someone has been making a hole in the bank
Dormouse-nibbled nut © Jen Bousfield
A dormouse-nibbled nut. Photo © Jen Bousfield

We also directed our cameras to the treetops, where streaming sunlight lit up the leaves as if it were springtime, and to the river, which was gushing by powerfully, with much white foam in places, after all the recent rain. At the take-off point for the mill leat, the river is dammed by a weir, with the leat sluice alongside it. The leat leads to a waterwheel that is still operating today – and generating electricity – at Trecarrell Mill, the home of the Armstrong Evans family.

Weir gate
Weir gate in the nature reserve
More Soprano pipistrelles amongst the foam insulation blocks. Apologies for image quality
Bats in insulated box
Less zoomed in, it is possible to see the design of the insulated box that is popular with local bats, and to see several bats inside
Bat guano under box
A pile of bat quano under the box with the largest number of inhabitants. It was rich, dark and crumbly in appearance
By placing something white directly underneath the Soprano Pipistrelle breeding colony in the woods, it was easy to differentiate the pile of bat guano from the rest of the soil. Photo © Tony Atkinson

Meanwhile, Jen and Jenny, with their group of followers, were checking the dormouse boxes in numerical order. Each box was opened gently and carefully, to avoid alarming any inhabitants. The bat watchers were keen to see a dormouse too, and so the dormouse box group offered to whistle loudly or send a runner if they found anything exciting. We received word of a wood mouse, but otherwise, heard nothing. Later, we met up with a pioneer dormouse box person, who gone on ahead and uphill, finding additional boxes numbered up to and beyond 60. There seemed to be about 67 in all.

A Wood Mouse paw is visible in the hole in this dormouse box. Photo © Natasha Underwood
A Wood Mouse paw is visible in the hole in this dormouse box. Photo © Natasha Underwood
Caught on camera – a Wood Mouse using a dormouse box. Photo © Natasha Underwood
Caught on camera – a Wood Mouse using a dormouse box. Photo © Natasha Underwood

Sadly, not a single box of the 67 inspected contained a Hazel Dormouse, although there were two Wood Mice, a Wood Mouse cache of nuts, and two blue tit nests, along with the sticky, accumulated debris from wax moths.

Should a Wood Mouse’s cache be cleared out of a box intended for dormice? Opinions differed, although apparently Wood Mice have been known to attack Hazel Dormice while competing for nesting sites, and even to predate upon their sleeping neighbours. I think I would nevertheless leave a Wood Mouse cache found in a dormouse-free box.

Wood Mouse nest found in a dormouse box.
Wood Mouse nest found in a dormouse box.

I hadn’t heard of wax moths, the bane of beekeepers. Apparently the grub-like caterpillars of the wax moth Aphomia sociella larvae destroy the nests of bumblebees, whereas those of Achroia grisella attack and and eat the honeycombs of honey bees. Beginning by infiltrating the nest with silk tunnels and galleries, wax moth larvae end up eating the bee larvae too. By the time they leave, they have also created a sticky mess that can wedge the lid down.

A sticky mess left by wax moth larvae, with a probable Wood Mouse nest underneath.
A sticky mess left by wax moth larvae, with a probable Wood Mouse nest underneath

We returned to the gazebo, where hot drinks, cakes and flapjacks awaited, along a track through the field that contained a section full of lovely striped mining bees, coming and going amongst a lengthy cluster of holes in crumbly ground. Having looked them up, I think that they are the Ivy Mining Bee Colletes hederae, which arrived in Dorset in 2001 (presumably from France) and is now the latest solitary bee to fly (August to November), feeding on ivy flowers, which are abundant at this time. The sunny sloping field so close to the woodland edge must be an ideal habitat for these insects.

The holes of an Ivy Bee colony in a sunny site by a path through a field near ivy at the edge of the woods

Next, we passed some fungi in the field. It’s been a good year for mushrooms.

One mushroom growing above another, with a handsome Arion ater slug on top of its huge dinner
One mushroom growing above another, with a handsome Arion ater slug on top of its huge dinner
A field that turns out to be full of natural treasures when you look out for them.
A field that turns out to be full of natural treasures when you look out for them

Having eaten a piece of apple and hazelnut cake and a flapjack (Jen is not only a great event organiser but also a generous and thoughtful provider of excellent refreshments, along with other members of LAPWG), I headed back into the wood to find Jen, Jenny, Pete and companions. I strode most of the way through the glorious scenery at my fastest walking pace this time (the first time I had been through Armstrong’s Wood on my own), and discovered them near the place where the bat checkers had left the wood, quite high up the slope. They were looking in the last few boxes, clearing out any debris. Jen had also found a group of cellar slugs in a box and was looking around for a rare fungus before heading back.

Cellar slugs Limacus sp. enjoying the shelter of a dormouse box
Cellar slugs Limacus sp. enjoying the shelter of a dormouse box
Tea & cakes are served
Tea and a variety of delicious cakes were served when we returned

Back at the gazebo, there was the chance to look at each other’s photos, offer each other tea and sample more cake. Despite so many boxes being empty, it was a truly glorious day.

Farewell to the reserve until the next time

To find out more about Cornwall Wildlife Trust and its nature reserves and activities, visit

To find out more about bats in Cornwall, visit: and, or you can always ask Cornwall Wildlife Trust if you have a question about bats or any other wildlife:

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