Bat and dormouse quest

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.

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 https://www.launcestonparishwildlife.org.uk, 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 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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

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.

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.

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.

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.

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.

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

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.

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.

To find out more about Cornwall Wildlife Trust and its nature reserves and activities, visit www.cornwallwildlifetrust.org.uk

To find out more about bats in Cornwall, visit:

https://www.bats.org.uk/support-bats/bat-groups/south-west-england/cornwall-bat-group and https://www.cornwallmammalgroup.org/bats-in-cornwall, or you can always ask Cornwall Wildlife Trust if you have a question about bats or any other wildlife: https://www.cornwallwildlifetrust.org.uk/wildlife/ask-wildlife-question