From Discovery to Recovery; Three Decades of Bat Science at Stackpole

In this episode of BatChat, we explore the significant roost of greater horseshoe bats on the National Trust's Stackpole estate in Pembrokeshire, Wales. With insights from conservationists Maggie Andrews and Paul Culyer, we discuss the site’s impressive growth from 200 bats in 1994 to over a thousand today. Paul recounts the early discovery of the maternity roost, while Maggie shares her late husband's innovative work with bat detectors that has contributed to over three decades of data. We delve into the bats' unique behaviors, vocalizations, and the impacts of climate change on their lifecycle. The episode concludes with a celebration of bat conservation efforts and the strong community bonds formed through this important work.

Leaving a review helps other listeners find the show more easily and spread the good word about bats. Don't know how to leave a comment? Check out our simple instructions here.

Chapters

• 0:04 Introduction to Stackpole's Bat Roost
• 0:20 The History of Greater Horseshoe Bats
• 6:03 The Impact of BBC Features on Bats
• 8:17 Roost Population Changes Over the Years
• 10:39 Maintaining Peter's Bat Counting Equipment
• 14:18 Peter's Journey into Bat Conservation
• 17:45 Collaboration Between Conservation Organizations
• 20:57 Effects of Climate Change on Bat Birth Timing
• 24:37 Foraging Behavior of Greater Horseshoe Bats
• 31:53 Discovering the Language of Juvenile Bats
• 34:13 Analyzing Bat Calls and Social Communication
• 42:53 Changes and Advances in Bat Conservation
• 44:48 Memorable Moments in Bat Conservation
• 46:45 Conclusion and Upcoming Episode

Transcript

Steve Roe:
[0:00] Last time we were in Hampshire learning about one of the first commercially

Steve Roe:
[0:03] Available bat detectors.

Steve Roe:
[0:05] Well, our location this week has made great use of bat detectors over the last three decades, and you're about to find out why at this important bat site in this episode of BatChat.

Steve Roe:
[0:20] Welcome to another episode of this brand new series of the Bat Conservation Trust's award-winning podcast, BatChat. I'm Steve Roe, your host, and this is episode 80. If you're new to the show, welcome. Episodes of each series are released every other Wednesday during the winter months until the spring. Just a mile inland from the Pembrokeshire coast on the National Trust's Stackpole estate, whose landscape is Grade 1 listed and spans 3,000 acres, lies a rather special Greater Horseshoe Bat Roost. We heard a little about this roost being discovered in our episode with Bob Stebbings. It's been featured on BBC Autumn Watch and earlier this year it appeared on Hamza's Hidden Wild Isles with over a thousand animals emerging. It's quiet as I park the car. A warm late afternoon in the second half of May 2024. No one is around. I walk down the side of the building to the end where I can see the clock tower I know I'm headed for. Maggie and Paul meet me by the archway under the tower. I spot the open loft hatch that I'll be sitting underneath later on to watch the bats emerge and record their calls, but first I have a podcast episode to record. We head up a small staircase in the walls of the building into a small office-like room. Old chairs sit alongside two desks either side of the room carrying ancient looking computers and other bits of tech.

Steve Roe:
[1:39] A single window looks out onto the courtyard. I spot a bat detector permanently situated on the windowsill, a cable running back along the walls to one of the PCs. And a doorway leads to a yet smaller room which ultimately leads to the loft door inside the void which holds the important roost which resides inside. We pull up some of the chairs. I'm with Paul Cullier who works for Natural Resources Wales and based here at Stackpole as a land manager working on National Nature Reserves, which includes Stackpole. Maggie Andrews is a volunteer and she says she's only really here because of her late husband Peter Andrews, who was a physicist and his ability to build electronics. He built the electronic beam array, a bat counting device which we'll hear more about in this episode. Peter died in 2011, but Maggie didn't stop the work. Instead, she continued collecting the bat activity data that they started together in 1994. At the time of recording, they have 32 years' worth of records. Back in episode 43, Bob Stebbings told us that two botanists found a ringed greater horseshoe bat, and Paul Cullier starts off by giving us the history of the site.

Paul Culyer:
[2:47] Yeah, so it dates back to the late 70s, when the Nature Conservancy Council had commissioned some thorough biological surveys of the Stackpole estate, as the Cawdor family were working towards disposing of their lands here in Wales. And by chance, one evening, one of the surveyors found a ring or potentially the story might be a dead bat with the ring on it. I'm not sure we quite know. But anyway, the ring was found and Bob Stebbings had been involved in that bat ringing event further east in Wales over towards Cidwelly. So, yeah, suddenly we discovered greater horseshoe bats here at Stackpole. They hadn't been recorded here before. Lesser horseshoes had certainly records from the 1930s of a visitor staying here with the family recorded lessers. So people were looking for things here back before the 70s. So suddenly, yes, a maternity roost of greater horseshoe bats was discovered here at Stackpole. And Maggie, just describe the building for us there.

Maggie Andrews:
[3:43] Well, it's a limestone building, which you could imagine it's an upturned cave as far as the baths are concerned. There's a clogged tower here, which is ideal because it's damp. Now, because people live in the building, it has some warmth to it, and I think that's important. And when they cluster in the roof, we've got cameras on the roof, inside the roof, and we can always find them on the side that's occupied and is warmer, and they're away from the side, which is not heated. So there's certainly an advantage there. The building is divided into flats and what I call the bat office. I think Paul calls it flat four. That has been very important to us because previously we used to have to climb up an iron ladder that was fixed to the wall. Then you climbed up an iron ring and you went straight into the loft through a hatchway, which you can see outside. Which is a bit of a surprise to the bats, I think. But Tom, we must mention Tom McCart because he's been very important to this roost. And he lived in a caravan outside at the archway here where the bats come out. Since 1978, he was here for about five years and he practically lived with the bats. So he is a very important person. We mustn't forget Tom's contribution.

Paul Culyer:
[4:57] After the sort of discovery of that bat ring, Bob Stebbings was involved and he'd had previous links with Tom who'd expressed interest and was beginning to get involved with bats through his adventurous activities such as caving. So this was meat and drink to Tom to go to places like this. So yeah, he was probably perhaps the UK's first paid bat worker. Prior to that, perhaps you could say that everyone else had been academic up until that point and then Tom's contract with NCC perhaps made him the first bat worker in the UK. Yeah, and his involvement stayed right through to his unfortunate passing away recently so hence maggie's point to our long data sets we you know thanks to people's dedication such as peter and maggie but also tom and my predecessor here bob haycock and annie haycock his wife we've got some really fantastic data sets which are really useful for us to start to discover things about this data now

Maggie Andrews:
[5:46] I gave a talk in anglesey once to the back groups there and the lady asked me what the talk was about and without thinking about it i said friendship. Because without those people gathered together in their collaboration,

Maggie Andrews:
[5:59] we wouldn't have the data that we've got we just wouldn't have it and.

Steve Roe:
[6:03] Like maggie said it's the rooster's in an a clock tower type structure and listeners might be familiar with it because it was featured on automot in 2022 so just give us a bit of the background as to how that happened and how the team there got the cameras in and you know what was the impact of the bats being shown on a nightly basis for two or three weeks

Paul Culyer:
[6:23] Well i think it was really successfully done very carefully filmed by the BBC cameraman very professional person Alistair Grubb a licensed bat worker in his own right so we followed all the protocols around that sort of thing and I think it's really interesting that those popular programs BBC One audience interested in wildlife were willing to sort of take on board that kind of content and find out more so I think that's a really good sign in its own right that the BBC and other filming companies and production companies want to come and look at these sort of slightly more obscure wildlife interests that we have so I think that's a really good sign about how we're perhaps becoming more concerned about some aspects of our wildlife

Maggie Andrews:
[6:58] Yeah it was great to work with he was very attentive and he had his camera angles, altered pretty well every day but he was very observant he'd never filmed the greater horseshoe bats before and we did actually find them when that was the season but it hadn't been filmed we'd seen it before but it hadn't been i had a video record of it but it hadn't gone out before, so I think it's important that people got to know a bit about what the bats were doing in autumn.

Steve Roe:
[7:28] And I guess it makes them more accessible as well doesn't it

Maggie Andrews:
[7:30] Well I think a lot of people have told me that they didn't understand about the greater horseshoe bats at all they'd never heard them never seen them and they were absolutely charmed weren't they by the antics that they got up to, and the fact that they could do backward flips they could flip there within a second they could flip round from hanging on the roof round to hanging on the roof.

Paul Culyer:
[7:54] Yeah, their acrobatics are impressive, aren't they? And I think, yeah, it just sort of opens up a group of animals that not everyone really favours. They're slightly scared of them in mythology and story and legend, of course. Bats don't always have a good sort of press. So I think that's really helpful, actually, isn't it? To help conserve our bats and people even a little bit more concerned is a good thing.

Steve Roe:
[8:14] And how many bats are we talking then over the last 34, 35 years? Well, how has the roost changed? Has it increased or decreased?

Maggie Andrews:
[8:20] Oh, it's increased. My goodness. We started off with 200 in 1994, and we got up to, I reckon it's over 1,000, I think, 994 was what Paul counted on his count. But the maximum count I counted was over 1,000, 1,100, because we're counting every night. You know, it isn't the same every night. It goes up and down. As I say, bats come from Slevich to join the population here. They go away again, et cetera, et cetera. We just, we've been looking after, I think that what we can say is that Tom Macowat and Bob Stebbings, that first collaboration was very important, because that was the time when the whole ethos of this roost was set up as what you might call minimal interference. The only thing that they did, When they first came to look after the bats, they did actually ring them, and the bats left. So they decided they would not bring bats. That was a firm decision right at the beginning. We do not interfere with the bats as much as we can. We stay away. And so when Peter came along with his infrared beam array counter, that was ideal because it meant you could passively count, not only occasionally, but every single night, the whole year, 365 nights a year for 32 years. So that's a hell of a lot of data.

Paul Culyer:
[9:40] Yes i can back you're right the graph looks wonderfully encouraging really we can go back a little further when the bat roost was first found it was certainly less than 100 adult bats here definitely um and it's now you're absolutely right it's over a thousand our count is a low estimate because we've missed some in our counting method but so it's definitely a minimum that we count so yeah we definitely got over a thousand adult female bats leaving the roost now at the peak of the season so you know that is a tenfold increase in that period of time so really good success story and i think you're right the the ethos of minimum intervention if we're working in the roost maybe looking at babies or counting babies if the adult return we leave we forget the count we'll come back tomorrow night and we'll try again rather than saying we'll keep going it'll be fine so we definitely use that method i think that's really important and

Steve Roe:
[10:28] I should have said you know the reason i've come here tonight is because maggie you're here for the next three weeks or so till june you know what apart from

Steve Roe:
[10:36] counting every night What sort of work are you doing here in that time specifically?

Maggie Andrews:
[10:39] Well, I'm trying to keep Peter's equipment going and that's a major job. As I said, Peter had nine counters going in various places. There's now one at Woodchester, which is still going. There is one that's in Bodridden, and there's one in Glencleven. But the Glencleven one I can't get to because the building that it's in is shut. It's locked. I don't know what they're doing with it, but it's been sold and resold several times in the last few years, and we don't know what's happening there. So sadly, all the equipment that I've got I've pulled into this building. So that's why you've got several bits and pieces all over the place i.

Steve Roe:
[11:18] Mean maggie says bits and pieces they are massive large cpu units like the ones i used to get at primary school sort of tell me what's on these things and what they do what they are doing

Maggie Andrews:
[11:27] This one has got stored data on it, i've had to bring that one um from a different site so that's why it's being set up at the moment it's not completely set up at the moment the one that was there in april i've had to take back for maintenance as i said because these things this is damp in the winter you can't expect computers to be continually active unless you look after them so it goes with a sleeping bag around it in the back seat of the car i've changed the monitor to a flat screen because these screens are ionizing and i don't i prefer not to use them but i mean that's that would be the kick do you know what i mean the infrared beam array that's under the table that we can see is the one that was built by Peter in 2004, And that's a metal frame one. The previous one that he built in 1994 is in the hole at the moment. Now, we can't see that. I can show it to you on the video, but it's like that one, only it's wood.

Steve Roe:
[12:25] So it looks a bit like a small window frame, but there's obviously electronics either side. And when it's plugged in, they're firing infrared beams across to the reflector.

Maggie Andrews:
[12:34] There are holes, top and bottom. There are five sets of holes at the top of each panel. There's two panels. One is an emitter panel, and the other one is a recorder panel. And so they're emitter diodes in infrared light so the bats don't see it because their vision doesn't include that light so they go through there without seeing it and it doesn't interfere with them at all and as they break the beams if it goes from the top beam to the bottom beam that's going out if it goes bottom beam to top beam is coming in so we can count them the direction not only that they're going out or coming in but the number that they're going out coming in.

Paul Culyer:
[13:10] That maggie describes that as a simple sort of break the beat but i know peter spent a long time getting the software right to discern if that's about to going in and out so there was a lot more to that and the reason why it's old cpu units is peter programmed in ms dos so an old computer language so yes but it still works and uh well

Maggie Andrews:
[13:28] That's the rolls royce kit there's nothing like it at all dietz has got a similar kit in germany but as far as i know he doesn't use it in the same way at all. And there's also, in Belgium, there are people who make a different type of counter. It counts in a different way. The way that Peter's counter counts is actually a much better way of counting. I can't explain all the electronics to you, but I can tell you that if it breaks one beam or two beams, it's counted as one, because you've got a wing going through as well as the body, and you don't want that counted as two. And also counts quickly so as you know the bats go out of here very quickly and at 40 miles an hour so it's got to be very accurate and very quick so he made the circuit he devised the circuit,

Maggie Andrews:
[14:13] and there's no spaghetti in there it is very neat and.

Steve Roe:
[14:19] Just tell us a bit about peter then if you're happy to i mean was it peter that got interested in bats because electronics and then you followed or was it the other way around and you know how did they get introduced to tom and bob

Maggie Andrews:
[14:29] Well peter as i say is the person who was the initiator of all this i've only the lot today only since 2003 of there abouts have i got in this bat business because i retired from work work yes he he actually got into bats because of a friend of his in university of liverpool who did genetics and he was interested in the moths because some of the moths are colored and some of the moths are not, and so why are some coloured? Because they fly in the dusk time and can be seen by birds but also have another mechanism of evading bats by clicking and it jams the echolocation and certain bats like certain prey so you've got to find out which of the prey they're after and which ones can be defending themselves by this. Now Peter got interested in the electronics of that and he thought well how are they doing that and how can it jam an echolocation call, now we were actually at woodchester at the time because this is where the bats from manchester went to do their field work for the moths and peter went down with jim and he got interested in the bats then and he was told about this chap called roger ransom who had bats in the valley.

Maggie Andrews:
[15:46] Now, we never actually got to meet Roger at this point. I don't know why, because we actually did have our first bat detector. It was an oscilloscope with a microfilm and a long lead, which we held out the window. Not portable. And I can still remember the Soprano Pipistrel sweep. You know, when you look at the Pipistrel sweep, the 45 kilohertz bats, I can still see it on the screen. And that was 1970s. And from then on, Peter got interested in the bats, and he did a lot of bat walking. He was the president and chair of the local bat group. He made his own bat detectors in the 80s, and we took people around the parks, and they got interested in bats. He then went to Wales to help the North Wales Bat Group do their hibernacular count with Tim Hodnett.

Maggie Andrews:
[16:34] Who had the bat boost at Bodrithan. And he was interested in how you would count the bats. And then Henry Scofield came along with his MSC and wanted to know about how you would count bats. So he was doing the project at Bodrithan. And the first bat counter that Peter ever made, it was one you could walk through because it was in a barn door. So the two sides of the barn door were multiple infrared beam arrays. I think there must have been about 20. I mean it's now just it's taken to bits that one but i still got the bits and the computer then was in tim's garage and it was an acorn computer yes definitely the bees and heaps in those days, so we've got a whole load of records from the lesser horseshoes of bodrytham and then people here got interested in what was happening at bodrytham you know news travels in wales and they wanted peter to make a counter for here so he came here and made the counter here, and then he also went to glen cleveland and put a counter in there and then he went to woodchester and put a counter in there and etc i mean as i say there

Maggie Andrews:
[17:43] were nine of them all together and.

Steve Roe:
[17:45] The data you've collected over that time you've handed a list of the papers about 13 papers or so published and there's another one about to come out later this summer and we'll touch on those in a minute Paul, you just want to give us your background just to your role here at Natural Resources Wales and what the relationship is between NRW and the Natural Trust.

Paul Culyer:
[18:03] Yeah, so the Trust took on the ownership of much of the estate, not all of it. Productive farmland was sold privately by the family in the 70s. But the heritage features that were remaining and land of sort of nature conservation interest, the lake system that we have, the warren, Stackpole warren, which was a rabbit warren back in Norman times, and the coastal sort of communities of vegetation and cliffs sort of all came to the National Trust, Decimal Beaches, So, yeah, we're here on the Castle Martin Peninsula, southwest corner of Wales. The estate was once much bigger when the sort of Cawdor family was perhaps in its pomp, and certainly prior to 1938, when it also included what is to the west of where we're sitting now, is the Castle Martin military range. So it was requisition land from the family in 1938, about 7,000, probably a bit more than that, actually, acres of land to have military training. So that really sort of divided the estate up, and the mod kept that land from sort of a compulsory purchase after world war ii so the estate changed quite a lot uh then alongside the sort of social changes after the world wars um so it came to the trust in 77 uh the cordor sort of sold off their their lane and their welsh lands and moved back to their sort of home in scotland as a welsh family even though they were here from

Paul Culyer:
[19:14] 1698 i think when one of their sons married the daughter of the previous owners so they ran for a long time that family here so yeah the trust owned it they became the owners we made it a National Nature Reserve back in 1982 and a site of special scientific interest and then in the late 90s that's several special areas of conservation the Pembrokeshire Lakes and Pembrokeshire Bats and Boston Lakes SAC the Limestone Grassland SAC and the Marine SAC that's just offshore so that all kind of reflects really that interest back even back in the 60s with the Nature Conservancy of why they want to put some effort into surveying this estate and finding out more about it and how the land might come into a sort of sensitive management for conservation because of that that real diverse mix of habitats cheek by jowl right through the estate really makes it a very very diverse place to be so i'm i work for natural resource as well as i say we've had a long relationship with them and part of my role is the sort of conservation advice and management of the estate to sort of help the trust sort of realize the benefits of these habitats and and the protected nature of the habitats and species before

Steve Roe:
[20:16] We hit the record button, you were talking about the influence of climate change on the roost, both in terms of how the timing of the bats has changed but also what climate change is going to mean for both those and bats in the future do you just want to explain that a bit

Maggie Andrews:
[20:31] More yes we've got a paper um actually we've got two papers that you could access that information in certainly the one that we have on foraging touches on it but also we've expanded it into another paper on the timing of the births and what we found with this load of data is with 32 years of data So you can do quite a lot. You can actually find out what's happening.

Maggie Andrews:
[20:52] And what's happening is that the mean birth dates for greater horseshoes has advanced. It's gone earlier, seven days earlier. The mean birth date is earlier by seven days. Now, that's quite a big shift in the time from 1980s to the present time. So we want to know not just the mean birth date, but what's happening in an individual year. Because in any individual year, it can be a warm year or a cold year or an intermediate year. Last year was an intermediate year and we've had several years in which we've had really early births where they've been in weeks six to eight which is actually out of the time that we normally count them and we wouldn't know that this is happening unless we had this data because with Tom's work with the babies in the forearm lengths we can determine when the babies were born and then we can find out what the shift is each year.

Maggie Andrews:
[21:44] So the take-home message here is that you can actually predict which are going to be the warm years, because there's something called a degree day, which is a calculation of environmental temperature. You take the average temperature, the maximum and minimum temperature, add them up and divide by two, obviously, and then you get your threshold temperature, which is the insect temperature, the temperature at which the insect will fly. Because unless that insect is flying, that bat's not going to get it. So the cockchafer is the important beastie here and April is the month that is the determining month for the birth dates in this particular for this particular species the greater horseshoe bats.

Maggie Andrews:
[22:26] So if you take April temperatures in your area, and you can go online at AccuWeather or Daytime and Date, those are two accessible weather stations, and you can find out your own area, which we've done for selected bat roosts, and we've found that over the years, there's only now Scotland, which is a cold year, and the areas where the greater horseshoe bats are, which is of course south and west, they're all warming. Gradually. It's not warm every year, but it is warm enough in enough years for us to have to take notice. So if we want to monitor properly, what we have to do is go to the April temperatures, do a little calculation, find out whether it's a warm year. If the temperature is between 110 and 154, that's a warm year. Then what you do is you count in week six to eight instead of later on which nine to ten because otherwise you're going to miss the peak count because the temperature in April tells us that's what's going to happen.

Steve Roe:
[23:30] The mean birth date has moved forward by seven days over 35 years or so that means it's moving forward a day every five years or so. What's that actually going to mean for that they're going to struggle to feed that their range is going to change?

Maggie Andrews:
[23:44] Well that's a very important point because the dependence on the cock chafer is relevant here, because the cock-chafer life cycle is temperature dependent as well. Not only the temperature at which it will fly, which is seven degrees C, but the temperature of the soil in which the grub will grow. So the grub grows over three years, and if those three years are cold, it means it's going to be slower and smaller when it comes out into being an adult. The prey and the predator is the scenario here. I think a lot of people understand that one, but they perhaps haven't got to grips with which insect is which bat, because each bat has its own prey insect. So, for example, a soprano pipistrol, it's the coronamids that come out of the lake, and their temperature dependence is January, February, March. So every species of bat is going to be affected, but it won't be the same for every bat. It depends on the insect that's involved.

Paul Culyer:
[24:37] I think just coming there, I think it's interesting and fascinating bit of work. And so I think what climate change is doing is put a bit of perturbation into the system and if our habitats and species were more resilient if we had bigger areas of land given over to nature and so on then maybe that resilience would help sort of buffer that perturbation but because we know they're often kind of on the edge of their range or certainly edge of their kind of viability then i think that's likely to be more significant isn't it and

Steve Roe:
[25:03] Then maggie showed us a picture earlier of the foraging range of these bats which was i think you said a couple of kilometers or so have you found that data out and i guess why are they only foraging that short range in the first few hours of the night

Maggie Andrews:
[25:18] Well in april the bats don't go out all night and so we have to calculate what i call the foraging time or the actual foraging time you can have either title if you like it's not the whole night i mean the bats some bats may be out all night but not enough it's got to be a reasonable amount of the population is going to get out. So you can reckon in April if they can get out for three hours that's good. If they get out for one hour that's adequate. If they get out for less than that it's not because they've got to be able to find their prey within that hour and a half which is the typical time for the real foraging time, the maximum foraging time for bats, these bats in April. And the 1.5 kilometers is we know that they can only go a certain distance in that time. so the 1.5 kilometers is the time you can go there and back in your foraging time, your actual foraging time.

Steve Roe:
[26:10] They return into, obviously later in the year, they're returning to feed the pups. But, you know, why are they not staying out that little bit longer to continually forage? Is it because they get enough food and they're then digesting food? Or is it because they go off to go and do other things?

Maggie Andrews:
[26:25] Because the temperature is too cold for them. The temperature has to be at midnight. It has to be 10 degrees. Or in fact, it's 8.45 is the average. But as a rule of thumb, if it's 10 degrees at midnight, you're going to get a good night's roost. root foraging. If it's less than 10 degrees, you not. It's because of their temperature dependence and their ability to catch insects and the insects that are flying at that time. That's the important thing. If the insects aren't flying, it's no good flying about. They're not going to waste time. They're like birds. If there's no food, they'll go somewhere else.

Steve Roe:
[27:00] And you've been able to, with those cameras, monitor that activity coming backwards and forwards. Where is all that footage? You know, is it saved on hard drives? Is it stored or is it not stored?

Maggie Andrews:
[27:09] Oh, it's stored. Initially, it's on three and a half inch floppy disks. I then convert that to put it onto a computer file. Because of the way that Peter collected the data, he actually had a program that would demonstrate what was happening the night before. And there's pictures on the wall we have in the BAT office that people can see to show the sort of data that's collected, and that's on screen the morning after the night. So the record programme is from 4 o'clock in the afternoon until 8 o'clock in the morning. That's because during the wintertime, any bat that goes out may go out at 4 o'clock because that's the dusk for the bats. So we set it to the maximum collecting of data that we can get. In the summer, they are going out, obviously, shorter and shorter nights as we get to June, July. And that fits the bats because the time they wanted to be out and getting their food is actually June, July. And at that point in July, the bats are getting more of a night. It's beginning to get a longer night. And they're going to get more food by foraging further away. So they need that time to go up further and further. And the lactating bats go the furthest. They go about 12 kilometers. And that was the work of Bob Stebbings and Tom. they actually tagged the bats and also Laurent de Bourges. He tagged them too.

Maggie Andrews:
[28:33] So we know all that data just from the paper record that comes out. I mean, we could print it out as you've got here, but it's stored, as I say, on the three and a half inch floppy disks and that goes to the computer. It's been stored on Peter's computer. That was transferred to my computer. It's now stored on two computers and three external drives. I should put one in the garage. Remind me to put one in the garage.

Paul Culyer:
[28:59] I think it's an interesting point. I mean, you've talked about the long run of data going back, a number of iterations of technological advance. So initially, paper files, handwritten notes, prints and slide images, eventually digital images, and then eventually electronic documents and through different formats of software. So it's actually surprisingly hard to maintain that archive of data it's really difficult we're blessed in Wales here to have a full coverage of the country with biological record centres four of them cover the whole of Wales which I think is a real blessing for us here in Wales that we have got a repository for data it doesn't have everything that we've done here obviously people's own data is their own property as they generate their own data but even so we try and get as much into the biological record centre as we possibly can

Steve Roe:
[29:47] And the rooster has increased massively over the last three decades. The landscape out there can clearly support it. Are there any aims to continually manage the habitat as it is for the pre-items and the habitat? What's the long-term plan, I guess, for habitat management out there?

Paul Culyer:
[30:03] Well, I suppose there's multiple features, one of which is our bat features, and particularly the greater and lesser horseshoes, of course. But yeah, we're lucky here at Stackpole, of course, that we happen to have a pre-designated site. So our bat designation could then take advantage of that much wider area so for most of our bat roosts that for example are sac bat roosts it is literally just the roost with no particular control over the environment of that site so here we do manage it and a lot of the management is for conservation we're particularly blessed being close to the sea with lots of sea caves i think that offers a resource for bats that uh that's special to this coastal location with limestone cliffs and as i mentioned the military range is 7 000 acres of relatively untouched neutral grassland it probably holds as large as expansive neutral grassland in fact which is grazed by sheep and cattle and the same for much of the grasslands here on the state so we're really kind of lucky but unusual sort of circumstance here for us to be able to do that and

Steve Roe:
[31:02] Paul you touched on the importance biological record center and you're trustee of the

Paul Culyer:
[31:06] Trustee of the wildlife trust which is a different organisation so in my spare time I work as a trustee of the Wildlife Trust South and West Wales here and of course we know that the conservation landscape of organisations in Britain is very unusual actually state actors like Natural Resources Wales natural nature conservation bodies but also a plethora of charitable bodies and the Wildlife Trust's office got a long history of working in the environment from the initial Norfolk Wildlife Trust which was the first that was set up so I think that volunteer-based activities is a good thing for society. I think it's something that we do very well in Britain, actually, about sort of how citizens can support their societies and in different aspects of that. So I think that's something very particular to Britain, but one that makes us stronger for all of that.

Steve Roe:
[31:49] And Maggie, so obviously you're a volunteer that's been doing stuff here.

Steve Roe:
[31:53] I think the first time I heard your name crop up was because of the work you were doing with the social calls of the horseshoes. Do you want to touch on that work? Because it's pretty groundbreaking what you've been doing. You've been listening to these bats with time expansion calls and in particular the social calls. And you've actually been able to start to understand the language of these juvenile bats. Do you just want to talk to us a bit about that then?

Maggie Andrews:
[32:14] Yes. When Peter put the infrared beam array in, Tom said, how do you know it's great horseshoe bats going out there? Because the roof at that time wasn't divided off as it is now. It was open. And at the other end of the roof, it's quite a big roof. There were less of horseshoe bats. And he said, well, you know, they can get through and they can fly out there. So Peter had to think. And being a scientist, he brought out a microphone on a long lead and a frequency division bat detector, which he made himself.

Maggie Andrews:
[32:45] And we heard sounds that we thought they were killing each other. We thought a cat had got in. What were they doing? Was it a male? Was it savaging the females? We had all sorts of theories about what was going on. Because it was a frequency division detector, it recorded any sound, and it didn't tell you particularly any details of the sounds. So the next thing we did was we put in a heterodyne detector, and the back detector was made by Peter as well. So we played it, we had a microphone again that was in the roof and we could hear it. And this is on audio tape now and wires stretched across here and goodness knows where. And we had videotapes running so we could see what they were doing when they were making these calls. But it was all a bit of a jumble at the time. And I could hear a particular call, which I can play for you if you like. Can you see on this, we've now got a screen showing where we've got a cascade of calls. Which are like echolocation calls, which go down in a series of steps with about a 5kHz difference between them. And then the last few calls are made through the mouth, not the nose, and that's a 28.5kHz. So this is a cascade. Can you imagine a cascade of calls? And here it comes. Do you want to hear it again?

Maggie Andrews:
[34:14] Now, that particular call is in John Russ's book, The Bat Calls of Great Britain and Europe. And that book is very useful because there's also the sound calls are available for you to listen to. And I think that particular call is to do with flight. It's emitted within the hour before going out and in the hour coming back. So it's like, I'm ready to fly. I'm going. Are you ready? Are you coming with me? and hi, I'm home. So that particular call is, I think, very interesting. And I heard that on heterodyne. And I said, I kept telling Peter, I can hear a difference in the sounds. It's like a sequence of calls. And he got fed up of me saying, I can hear them, I can hear them. And he bought a time expansion machine, which was a David Bale Tranquility 3, Tranquility 2, I think we first had. And when we got those calls, I was in heaven. I'd just retired and I was quite happy to sit in this bat office and there's a chair here which I used to sit on which is now completely wrecked because I sat in it for so long.

Maggie Andrews:
[35:24] And we then found there were 28 categories of call, now there's another call which is quite a nice one which Roger Anson calls pot hooks, you know when you're learning to write you do pot hooks and hangers pot hooks and hangers those calls are particularly interesting because they indicate what the bat is the bat is telling its mates what it's doing now this one isn't isn't quite so easy to see on the screen we've got, what roger anson was calling pot hooks it's a sort of j upside down if you can imagine that and there's about five kilohertz difference and they go in a sequence and this is what they sound like.

Maggie Andrews:
[36:07] So that the bats are indicating they're going to fly again when they make that noise. That's another call that's frequently uttered before the exit and on the return. This particular call that I'm looking for, you can actually listen to it outside. You don't have to be inside. You have to be inside the roost to hear those two. I'll give you number 12.

Maggie Andrews:
[36:33] Sounds like a seal, doesn't it? It does. and it's because it's got all these oscillations in it and that is a social call which has got, individual characteristics at that that's that particular call is a male or a female advertising its presence to the rest of the community so you can there are lots of other calls that you can listen to outside the roost there's one that sounds like a barking dog, i could play that for you if you like would you like a bit of that.

Steve Roe:
[37:37] Not the sort of sound you want to hear when you're surveying by yourself, is it? And just while that's plain, Maggie, I mean, obviously the ones outside, you can see what the bats are doing. You know, you've got the detection, you can observe the bats and observe the behaviour. For the stuff that's inside the roost, have you had to match up the timings of the cause with what you can see on the video? Yes. And is that how you've done it?

Maggie Andrews:
[37:57] Yes. Hours and hours of sitting in the chair, I tell you. And it was a joy to do, but it did take a lot of work because Peter had this bat detector, which he, of course, modified, so you could put it somewhere for 24 hours. And we also made recordings in caves in Devon, in the Chudley Caves. And it meant that you could go in at lunchtime and you could put your bat detector there and you could go out, come back the next lunchtime and collect it, or even just change the batteries and make it run for another 24 hours. And so that's how we got all these calls. It wasn't a matter of just listening to one or two minutes. You really got to get the time in. And the longest ultrasound call is 300 milliseconds. And every night you put that in, it was four hours solid because it's voice activated. So every single minute was taken up with sound. So you can imagine the numbers of calls that we had to analyse before.

Steve Roe:
[38:51] So you've got 28 categories of calls. Obviously, that's an amazing amount of work and amazing work to have achieved. There are obvious uses for that. But I'm thinking in terms of people like myself who are consultants, who are going to a roost and they're maybe doing the internal and external, maybe seeing the bats, maybe not depending on the time of year. And then they're doing the three surveys. How can this information improve the sort of survey work that we're doing, I guess?

Maggie Andrews:
[39:17] Yeah, so we just go back to bat sound again. We've got baby calls. The adult social calls are developed from the baby infant calls because the babies are born, they're not able to eclogate, and it takes them four weeks to really get to the adult eclogation because they haven't got the shape of the mouth at all and they can't fly either, so they're stuck in the roof when the mummy goes out. So the first thing they do is do what I call the wah-wah call, which is one that you cannot miss if you're a mother these are the baby coils in the rooster, That goes on the whole time when the babies are born. So it's a good thing you can't hear the way you go.

Paul Culyer:
[40:06] You wouldn't stay in for long.

Maggie Andrews:
[40:08] It's deafening. And how the mothers cope. They can actually determine their own baby by the number of frequencies and the harmonics in the call. And you can see that there's the fundamental, which is about 12 to 15 kilohertz, and the rest of it, that's made in the mouth.

Maggie Andrews:
[40:25] This call is not nasal because it can't echolocate. It hasn't got the right shape of mouth at all to do that. It just shrieks, really. Mummy, mummy, mummy. And they're in doublet. They're in twos. The lesser horseshoes do them in threes, and their echolocation comes in higher, so they've got more harmonics. But we ought to say to the folk listening that the greater horseshoe bats and the lesser horseshoe bats, the social cores are in the same frequency range, which to me means that these social were made by the ancestor of the two bats. It can't be that similar and not have a common origin, I don't think. So if you're a surveyor and you've got a nice fancy time expansion detector, a Pettersen or something like that.

Maggie Andrews:
[41:11] If you can possibly put a little bit of plastic on it, except for the microphone, and if you go up a ladder and you just tuck it into the roost, you don't have to go in at all, just prop it up with a brick, half brick or a piece of wood, so the microphone is facing upwards towards the apex, because that's where the babies are, and if you just leave that there for whatever memory time you've got, you will probably pick up the babies. Now that saves you an awful lot of time if you're if you're wanting to know is that roost a maternity roost then you can put that record in and you get it and scotty dodd has done this in sussex with the roost that they found and i think they were able to then identify that roost as a maternity roost and that helped them to get the vincent vote to buy it for them yeah i think that was important piece of work there by scotty dodd.

Steve Roe:
[42:02] Your name came up when we interviewed scotty last year do you think that the other bat species have got a similar thing going on. Do we know if anybody's done anything on those?

Maggie Andrews:
[42:11] Maggie Brown very kindly gave me some records and I'm trying to encourage more people who have bats that are injured to do any social calls that they can because we need a library of the baby bats. If we can possibly get a library of baby bat calls that will help them to identify those roosts of those species and certainly the Pippa straws have been quite well studied haven't there for their social cause and it was tom actually who told us about soprano pips and their social cause which we used to call chunking because of course we didn't have the fancy bat detectors at that time and that's what it sounds like on a heterodyne bat detector but yes all the

Maggie Andrews:
[42:48] bats the soprano pipistrels are important and the pipistrels is important as well how.

Steve Roe:
[42:54] Have you seen bat conservation change over the years and do you think it's going in the right direction and what do you think we can be doing better?

Maggie Andrews:
[43:01] Well, I've certainly seen changes in the situations regarding who is actually monitoring that. Certainly, it's gone from a much more academic, as Paul was saying before, gone from more an academic society to more of a surveyor society. But the main thing is that people are getting out there and finding the bats and finding out what they do and how to conserve them. And the more information we get, the better. I mean, Bob Stebbies was saying when you interviewed him that he owns up to having disturbed the bats, and he's learnt from that, and we've learnt from that, that you mustn't disturb them, you must leave them alone. And this is why I think the more people do the automatic counting the better because you get just so much information.

Paul Culyer:
[43:44] I think, obviously, we know all our backspecies are protected. And I think it's that protection that has worked in this case. It is possible for people to look at the UK wildlife protection legislation and say, well, it hasn't really worked. And to a certain extent, that's true. But I would say it's true because we've never resourced it to the way that we should resource it. So it's not necessarily a fault of the legislation. But what we do know is I think we've penetrated the construction industry, architect industry, those sorts of businesses that are now much more alert to their requirements uh legal requirements in terms of of what they need to do to protect bats and i think that's been a big step forward for bats and of course we do know that a lot of the monitoring records for bats are showing some good news stories around some of our bat species definitely so certainly the ones associated with buildings so i think that's been a real help and i think that general awareness of our nature and wildlife has helped and of course in recent years nature is on the political agenda more than it has ever been in in my sort of 30 years of working in nature conservation mostly here in Wales so I think there's a few things coming together on that it's still lots to do but I think the bats are a good news story.

Steve Roe:
[44:48] Over the years what have been your most memorable moments anything that comes to light?

Paul Culyer:
[44:53] Following Tom crawling through a Napoleonic fort small gaps where Tom would say oh it's just a bit of a drop and down you go Tom McCout was incredibly adventurous and great fun to be with and amazingly energetic in his and that's why he learned so much and that's why we've learned so much from him so yeah at any times and but also of course with maggie peter i did know a long time ago when i worked here initially in pembrokeshire and bob and annie so those people have been really fantastic and have been great fun to work with

Maggie Andrews:
[45:23] Yes, I think when we put the microphone in and we thought they were killing each other, I think that was a moment to treasure. But also thinking back to Tom and what I call the Stackpole crew and the way they work together, I think, has been a joy to be part of that. And certainly watching that count, you know, when Tom was doing his measurements of the forearm length, he did it so professionally. And Bob was up the ladder. He got his box. He got the baby bats down. and he would say which section he got them down from, which number, it's numbered one to seven, north and south, while the pats were peeing on his head. And he didn't wear a hat. And then Annie would be sitting there doing all the records. So it was a team, and I think the teamwork has been the thing. And by the way, I should have said before, when we were talking about records, Tom's records were on paper, but they were very good. He kept them thoroughly. And when he gave them to me in the year before he died when we were writing that paper and I'm so glad that we did write that up because I think we would have lost all that otherwise, just seeing what he'd done and the fact that Peter was able to calculate the pub age from the forearm length that partnership was very important and the people who went with it the crew, Stratpole crew that went with it, the friendship bit has been very important as well I think.

Steve Roe:
[46:45] That's what it's all about Yeah Maggie and Paul, thank you both very much for your time.

Paul Culyer:
[46:51] Thanks, Steve. Thank you.

Steve Roe:
[46:53] Thanks again to Maggie Andrews and Paul Cullier for their time. After that interview, I set up underneath the archway with a detector to watch the bats emerge. Next time, we'll be down in Cornwall with Professor Paul Racey, talking about his distinguished career with bats. Until then, I'll leave you with the sounds of greater horseshoe bats emerging from Stackpole on a May evening.