The Bechstein's of Bracketts

S5E46 Hidden in west Dorset is a nature reserve which holds a very special secret. A bat box scheme which was installed in the late 1990's is home to one of the most well-studied colonies of Bechstein's bats. Join Steve as he spends the day with the Vincent Wildlife Trust and Dorset Wildlife Trust as they undertake one of their monthly inspections of the boxes, adding to this really important data which has been collected over the last quarter of a century. We hear from Patrick Wright, VWTs senior scientific officer about the history of the scheme and what new discoveries are being made, Steve Masters, Dorset Wildlife Trust's reserve ecologist who tells us why the woodland is such a special place and a familiar voice to regular listeners; Jim Mullholland who has recently joined VWT explains how the team are processing the bats as silver-washed fritillary butterflies swoop around the dappled sunlight hitting the woodland floor.

• Bats at the Vincent Wildlife Trust
• Dorset Wildlife Trust
• Dorset Bat Group
• Maureen Keats dedication

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Transcript

Steve Roe: 0:37

Welcome back to BatChat, the award winning podcast from the Bat Conservation Trust for anyone with a fascination in these amazing nocturnal creatures. I'm Steve Roe, and this is BatChat series five. Yes, hello, we are back with a brand new series and episodes will be released every other Wednesday from now until spring next year. If you're new to BatChat, welcome along. I'm Steve Roe. I'm an ecologist and in my spare time a trustee for the Bat Conservation Trust. We've had a really busy summer, as you heard just then we are now an award winning podcast, thanks to the Chartered Institute of ecology and environmental management, who named us as the winner of the NGO Impact Award 2023 for making a significant difference to the conservation of the natural environment, as well as spending this year recording conversations for this new series. We're also really grateful for those of you who completed our listener survey at the end of the last series. We've spent the summer going through those suggestions, and we'll be implementing as many as we can over the coming series. One of those suggestions was to have more species specific episodes and so here we are an episode all about the Bechstein's bats. This episode comes to you from a Dorset woodland. It's a place I visited several times for over a decade and the approach involves driving through a narrow dorsal lanes with lovely tall hedgerows VISTAs appearing where you can follow the hedges across the landscape, forming the boundaries of small field parcels. Meeting staff of the Vinson Wildlife Trust and Dorset Wildlife Trust at the entrance to the woods. This conversation starts as the team begins to check the bat boxes spread throughout this reserve. So it's the middle of August and I'm in one of my favourite places in the world to come and see bats on down in the depths of Dorset and Steve Masters from Dorset Wildlife Trust is going to tell us where we are and a bit about what we're doing today in the woodland and why the West Woodland is so special.

Steve Masters: 2:36

Yeah, so we are in the darkest depths of West Dorset brackets coppice so the site here Dorset Wildlife Trust data reserves 45 hectares it's a mixture of a lot of different habitats from semi natural woodland. It's on the ancient woodland inventory, which is where we're stood now to neutral meadows, unimproved. We've got a river that runs through the middle, as well as also some wood pasture. Trust has been involved here since about 1964. So that's the Wildlife Trust. And we took on the main block of the woods in 1987. And then since then, we've acquired other parts of the wood with the last bit been acquired at 2002. And today we're out checking the bat boxes, which were put up in 1998. I think the first ones by Dorset bat group, and a lady that was very involved with that was a lady called Maureen Keats. And she was also very involved in brackets caucus and she loved reserved and since then VWT Vincent Wildlife Trust have put up more bat boxes. And we're out checking for the maternity colony of Epstein's

Steve Roe: 3:47

and the woodland is saying some woodlands like we're looking, we're stood in just off the footpath and it's quite difficult to see very far through the woodlands. So if I can see the next day long after that it's quite a enclosed understory, isn't it? How old do we think the woodlands is Have we got any idea at all?

Steve Masters: 4:04

Well, if it's on to Part of it's on the ancient woodland inventory, which I think means it's at least been around since 1600. But the likelihood is that parts of this would have been a lot around a lot longer than that. As you say we've got a canopy of oak and ash mainly with some birch. And then underneath we've got a hazel Holly and in places maple understory. And previously in the woodland, some areas were coppiced, and we reintroduced a bit of that coppice a few years ago. And so we're just doing very small sections though. Obviously, the woodland is is very precious for not just the back Stein's, but all sorts of other species, including door mice. We get a quite a nice orchid called bird's nest orchids, which is a parasite or saprophyte. And yeah, and we've got in brackets total. There's 2799 species recorded since we've taken on the reserves.

Steve Roe: 5:06

And what's your role at Dorset Wildlife Trust about

Steve Masters: 5:09

the Wildlife Trust? I'm the ecologist. So I go across all the reserves in the ecological survey work, anything from floral surveys to inverts to bats. And then with the bat group, I was on the committee for Dorset bat group up until about a year ago. And then yeah, then a lot of work with Dorset back group over the last sort of 20 years I suppose.

Steve Roe: 5:32

And how does this compare to Have some of the other reserves obviously you're in Dorset you've got things like the Ladybird spider and all those other sort of iconic British species. How does this compare with some of those other sites?

Steve Masters: 5:42

Well, as far as Dorset wildlife trusts go, this is probably my joint favourite reserve, I have to say. And not only because of the woodland, but also we get Marsh artillery butterfly in the meadows, which is quite a rare breeding butterfly species in the UK and Dorset. And, and we also get those other nice species like we I think we've got about maybe 400 or so species of mosses, liverworts, in lichens, some of them quite rare. So yeah. And it's quiet as well. Because we're in a hidden corner of West Dorset, you very rarely see anybody here.

Steve Roe: 6:15

It's great for recording. This is like ideal. There's no cars, there's no traffic, there's no background noise, just the sound of people doing decent conservation work.

Steve Masters: 6:23

It's a great spot. It's a really nice spot if you want to come for a walk and not see anyone and just get immersed in the woodland really.

Steve Roe: 6:34

And there's a bit of woodland coming up. Haven't been having pasture. No, that's an open pasture over in the middle. Why is that area still grey, Steve?

Steve Masters: 6:43

And so yes, we've got a section of woodland. There's a couple of sections woodland, one section that was conifer, where conifers were taken off. And then a section that has been opened up slightly a bit more by taking up some of the ash, which has been restored to sort of a wood pasture landscape. And so which is a really vital landscape for a whole lot of species. The heterogeneity of that kind of landscape is brilliant for all sorts of invertebrates, bats, door mice, you know, all sorts of species really. So yeah, so we're doing that. So that's why it's grazed by currently a nice herd of Highland cattle. Nice. Yeah. So yeah, they spend pretty much the whole year out here. And then the off the kind of wetter bits in winter. But yeah, mainly the whole year. Yeah, they do a good job at eating the kind of roughest.

Steve Roe: 7:37

And driving through the country lanes going, Hey, this sort of it's quite hilly, hilly landscape, and you get sort of two little vistas. And you can see all these blokes woodland are really well connected, how well connected his brackets coppice to the rest of the landscape.

Steve Masters: 7:49

Yeah, so it is really well connected. So from here you as you stretch out from the woodland on various different hedgerows and little compasses, and it connects into some other big blocks of woodlands. So for example, from here, it connects over to our reserve at Kinchen meadows, which is probably about 2k away, but it's all connected up by hedgerows. And from there, it connects into Powerstop common, where we know there are other maternity colonies of Bechstein's bats. And then it connects up the other way over the border into Somerset. Yeah, so it's really, really well connected and obviously got chattington woods as well, which is nervous. So yeah, so it's the perfect kind of connected landscape for bats to be able to move around.

Steve Roe: 9:14

And is there any part of the reserve open to the public or was all completely private for you guys?

Steve Masters: 9:18

No, it's all open to the public. Yep. So although you don't you rarely see a person out here. It is all open access. Yeah. So most of our reserves are all open access. There's just a few where we might have like farming operations that we don't allow people. So yeah.

Steve Roe: 9:36

So we've just heard from Steve, a bit about the woodland and its importance. And he's mentioned, obviously, we're checking boxes today, Patrick, you want to introduce yourself? And then how many boxes are we checking today? And who's helping us?

Patrick Wright: 9:47

So yeah, I'm Patrick Wright. And the senior scientists scientific officer at the bins and Wildlife Trust. And so we are wet rag is called this because a really special site, because we have 85 bat boxes that we're gonna check. We're with a group of volunteers, with the hope to find the maternity colony effect size bats, that we've been ringing for 24 years now, we've already found two boxes with some bats. And I think we were just doing some more checks. And hopefully we processing them later this afternoon. So

Steve Roe: 10:20

just tell us a bit about the type of boxes we've got, why this why this style been chosen. And you say you've been bringing them for 24 years, did the box appear almost immediately? What's the history of the site? Yeah.

Patrick Wright: 10:30

So it's actually a really interesting history for this one. So it started back in 1998, I think in March 1998, where the Dorset bat group thought it would be a good idea to put up a few boxes in this reserve. And three months later, I think they had a whole maternity colony of Bechstein's bats. And so that's quite special. It was a huge discovery because back then, we only knew of one colony in the UK, and like just the odd records in the hibernation sites. So this was a huge discovery with a second maternity colony and also like an amazing opportunity to do some research to learn more about this probably the most elusive bat in the UK back then. So the following year, depends on wire trust UK on the ringing scheme. So they've been ringing the bats Every year since then, so this was mostly done by Colin Morris back back in the days. And now my colleague Marina has taken over. And so we have yeah, like I said, 85 to 82 fN boxes in The Woodlands. And so these are sort of made of cement and sawdust, and kind of mimic the perfect rooster backsides batch was just a woodpecker hole. And then we have these bigger, much chunkier one FW ones, the hibernation boxes, which are very similar, but just big chunky ones where we tend to get the whole maternity colony with all the pubs back in when the month of June and July, that's where they tend to be.

Steve Roe: 11:56

And how big is that maternity colony? Has it grown over the years was it stayed fairly consistent?

Patrick Wright: 12:00

So we think that the colony has stayed fairly consistent over the years. That said, we have had like our peak years over the past two years with I think we're just last month was our highest number with 121 bats, roughly 70 adults, and so 50 juveniles that we ringed and so yeah, we know how they are. Each single bat here. So we actually had our oldest baton ever recorded back in in May, and she's 18 years old. And

Steve Roe: 12:32

you know how old they are? Because you've been able to bring those juveniles when they're large enough to be ringed? How many then are you bringing each year? And do you end up? Are you confident that you catch and wring every juvenile? Or do you do subsequent checks? How often do you do the checks? And do you end up ringing later in the year when you find the last few stragglers?

Patrick Wright: 12:50

Yes. So in total, I think we've received close to 1000 bats over the past 24 years. And we're fairly confident we get all the juveniles, but actually once, so I would say 50% of the population disappears once they are well past the first few months, because we never see the males once we ring them. They tend to live solitary lives. So we get very few recaptures of the males. And we only tend to recapture the females who just are very consistent visitors of these, these boxes. So yeah, we tend to ring all the Youngs in late July when they're when we think they're sort of big enough pretty close to adult size. And if we think some might be a bit too small, yeah, so we just wait the following month, see if if they're there and ring them but yeah, I would say we probably get 95% of the population maybe maybe close to 100%

Steve Roe: 13:51

and you're waiting to ring them to get to a certain size so that things like the ring don't slip off the wink. We've listeners will have heard us talk about ringing before but just has been ringing and then you mentioned recaptures there. Do you ever get recaptures offside? Do you get records from local back groups in the area?

Patrick Wright: 14:05

Yeah, so the ringing is essentially just putting a little ring around their forearm and so we just want to make sure backsies bats take rings quite well. We've rarely very rarely have issues with other species. You can have issues, but very rarely have issues with the back Stein's. Once we put them on we get to recapture them check their ring numbers. We have very few recaptures outside. So I think Colin found a few males in a woodland nearby. That's the only bit of history of recaptures off site I've heard ya know, and when we're not 100 Central, where these bats tend to swarm. So this is when, in October, the back Stein's and particular Myotis bats also tend to travel fairly long distances to get to these hibernation and mating sites. And so it can be up to 20 or more kilometres. But we yeah, we don't seem to get these females at any of the swarming sites so we're not quite sure where they go for the hibernation as well

Steve Roe: 15:09

as scuffling in the background as Jimmy is struggling to get onto the ladder because the amount of undergrowth it's a really nice bit of woodland, isn't it? Have you ever done any work in terms of working out where the bats foraging the woodland? Do they foraging this woodland or do they golf site?

Patrick Wright: 15:22

Back in 2001 of the very first radio tracking studies for the species happened in this woodland So Colin Morris and Henry Schofield spent the whole summer just tracking some of these bats think about a dozen of them. And so backsides are really sedentary that very few of them actually left the woodland. So I think out of the order bats are they radio tracked, they use about 75 hectares, which is actually a really small area. They raid attract a couple of males as well. They moved by maybe 100 metres from the night roost, the females would met sometimes go a bit further away. But uh yeah, they are very sort of sanitary foragers these these big stones.

Steve Roe: 16:04

So we've got about 10 volunteers today and the other team with Marina have split into and they're going the opposite way round, so we're sort of working towards each other and a big circle around the woodland. How long do you reckon this is going to take to date? Are we out for the full day

Patrick Wright: 16:16

If it will be a full day for sure that we started bit after 1030, then I reckon we'll probably be done by one o'clock. Then after that, we'll be tackling the boxes with all the bats. And so it should be a fairly quick process today, although we probably might get 100 bats, but we've done most of the bringing last month. So there'll be very little ringing to do hopefully this month, we left a few actually, we think we had four juveniles last month that we didn't ring because we thought they might be a bit too small. So might bring those ones but other than that, we'll mostly be processing the bat. So we'll be reading the ring number, measuring the forearm, wearing them turn about their reproductive status. So whether they're lactating post lactating, probably this year, because the Youngs will be a bit more independent. And and then we just put them back in the box. And, yeah, there'll be done for the day. And we will also be done.

Steve Roe: 17:12

You said we might get 100 bats so casually. I mean, it's a really special site. Why is it the you'll have bats and why do you enjoy working with DWT so much?

Patrick Wright: 17:20

I'm very lucky with Viola tears, I'm so I'm a senior scientific officer, which means I don't work just on bats. I also work on carnivores. So I have the best of both worlds. So yeah, I definitely like keep myself busy with lots of interesting things. And that's, I think, I think what I find particularly interesting with with this species as well, so, Vito to fund in my PhD, which was actually on backsies bats, and I think for such a small animal here that they live such long lives, which is very unusual already. But their behaviours tend to be a lot more similar to other sort of large animals like elephants, or killer whales, for example, where they have these maternity colonies, where the females sort of have a lot of knowledge on where they need to roost. And so they share a lot of information. And the males tend to live their boring solitary lives. But actually what we find and in sometimes in September checks, we have a bunch of juveniles, like 15 juveniles, with two or three or four oldest females. So these bats are about 15 plus years old. And so studies that are done on cutaways, in particular, tend to suggest that is like these old females tend to play a huge role in sort of knowledge sharing, teaching, or the young ones, where the food is where the roosting sites are. And my theory is that the back Stein's also have similar behaviours, where they're just trying to share as much information as possible to the young ones. So that, no, they just know how to sort of find all the food and the roosting sites to survive for you know, another few years. 17 If they can, or 19 is the record for female so you

Steve Roe: 19:13

guys have just finished checking these boxes. So shall we get into it small boxes, then we'll talk a bit about the ecology of Epstein's short legged Yeah, and

Patrick Wright: 19:24

we never can never find it.

Steve Roe: 19:28

So, we've just crossed the grace matter that Steve mentioned earlier on, Patrick should just want to give us a crash course in Bechstein's bat ecology then.

Patrick Wright: 19:36

Yeah, so the best sign is bat is what we very much call a woodland specialist. And that's because so the maternity colonies in particular are specialised into roosting and woodpecker holes. And so not only are they recent woodpecker holes, but they need a lot of them. So about, maybe they can use up to 50 different routes within a single year. And they also don't like to forge very far. So they need essentially a place with lots of woodpecker holes, and lots of food nearby. And so, this definitely fits of the woodland sort of habitat, especially ancient woodlands, where you have lots of different insects to eat. So actually, backsides are not super specialists. When it comes to their diet, they'll eat pretty much anything they can find. But they need a lot of fit nearby. So very much a wooden specialists that will never forge very far from sort of their roosting sites. And the males, obviously are not as fussy because they don't need to lactate they don't need to feed their young. So they can use sort of what we call sub optimal woodland habitat. And we can find them roosting in sort of lots of odd little crevices and they're not so dependent on the woodpecker features. We haven't been these ones before might get the odd ones I don't even the ones over there. We've got had like the odd like to the bats, even after leaving. Oh, maybe yeah, possibly. Yeah.

Steve Roe: 21:17

So Patrick, you said they like, naturally woodpecker holes, why then obviously there's loads woodpeckers in this woodland. Why are they favouring these boxes? And how are you confident that they're not elsewhere? In those more natural risk features, then?

Patrick Wright: 21:30

That's good question. Actually, so Colin, who did ringing, he always said that he very rarely sees woodpecker holes in this woodland. So although like, it looks like a perfect woodland, where it might be fulfilled, like a house, maybe one of the reasons why the bats moved in right away into these bat boxes was because they actually we're missing a few sort of key features. And obviously, we only do one check per month. So we don't have the full picture, maybe they are using other other actual real woodpecker holes. But the fact that we're we're just we can predict really well, their behaviour. So we, pretty much every month we get the bats and we know that in in May, we'll get the bats in different groups. And then June, July, the maternity colony will pretty much always guarantee that we'll get them in the big one FW boxes. And again, in the, in the August September checks, pretty much always guaranteed that we're gonna get maybe three little groups of bats in the woodland. So we can't be 100% Sure, but just my experience, I think we can sort of get an idea that they seem to really like these boxes. And maybe it could just be a fact that there's, they just love these boxes here. Or, and there's they're lacking some key features in this woodland for the bats to use them, as well. So maybe it wants this, maybe that if there's more sort of features, and the trees further down the line might actually stop seeing them. You know.

Steve Roe: 23:18

And you said earlier, they're quite rare about the special bath, because obviously a lot of gaps in the knowledge. And that's one of the things that your PhD was doing was trying to fill one of those gaps on it tells a bit about the PhD where you did. Yeah. So

Patrick Wright: 23:31

during my PhD, I was a lot focused on population genetics, and understanding how sort of populations in the UK are connected, and how the landscape affects this. So we sampled a lot of colonies in the UK, and looked at the levels of inbreeding. Because you'd think, as a woodland bat, very, very specialised into living within a woodland habitat fragmentation might impact sort of how these colonies are related. And maybe you'd have higher levels of inbreeding, as I mentioned before, they also swarm which is really linked to the species ability to disperse when it comes to mating. So actually, what we found is that the although they're very sedentary and stick to their sort of local patch of woodland, when it comes to sort of foraging and summon breeding, when it comes to the mating season, they're very willing to go very far. And that sort of really helps for the survival of the species, and linking different populations actually, in some are not linked at all. So actually, that's what we found is that there's very little sort of population structure within the backsliders population. So all of these populations seem to be fairly well connected, except for one population, actually, which it stands out on when you look at the range of backsides bats, it's in Buckinghamshire, so it's this burn wood population where there's only one very, very isolated as the only population where we found actually quite high levels of inbreeding. So this could be that they're not just the distance to travel to reach other swarming sites might be too far. So they're not connecting with these other the main population that might be impacting that. So I think, yeah, that they're willing to sort of maybe travel up to 20 kilometres through sort of sub optimal habitat to reach these swarming sites. But more than that, I think it starts impacting the genetic structure of the population. That said, habitat fragmentation will affect them at a much sort of, not at a genetic level, but maybe just the survival of the population. You know, if you're cutting trees down, there'll be less food, less routing features that will affect the survival of a colony in a bit different way.

Steve Roe: 25:53

So how did you go about collecting all that data then? Was it were you using existing data? Were you going travelling at different sites and then how you're actually getting the genetic material?

Patrick Wright: 26:01

So we take wing punches for that, so do a little hole in the wing. So we have to do it under Home Office licence actually doesn't really harm them. So we sampled eights eight colonies, so there are a few other box games How in the UK. And then the rest was done with some trapping. So we put do some heart traps and acoustic laws, which is like the typical way to catch backsides bats and woodlands in the UK. And so that helped us sort of get a sort of increase our data, sample size. And then so then it was straight into the lab, extracting the DNA, and we did PCR, we're looking at the levels. So looking at heterozygosity so for example, heterozygosity and homozygosity in different sites within the genome of the each individual and from that we can sort of determine sort of the sort of statistics the levels of inbreeding, how connected each population is and so on. You

Steve Roe: 27:05

make it sounds so simple. And when you say a hole in the wing, it really is a tiny little hole in the wing, isn't it? Yeah, so

Patrick Wright: 27:11

it's these biopsy punches that are to three millimetres depending on what you use. And yeah, within a month the bat orphans tend to heal we've well after a year you can barely tell that they've been sampled. So yeah, so that wing sort of tissue is one of the fastest healing mammalian soft tissues from what I've heard of. And yeah, it does definitely seems to heal really fast.

Steve Roe: 27:37

These guys have done these boxes so crack on that's not so you can hear on the audio track how much noise there is as we're walking through the vegetation. Patrick just want to describe how dense the understory has and why understory is and why is it the backsides love the understory canopy so much. Yeah,

Patrick Wright: 28:00

so it's very prickly in this area where we are. It's just covered in Holly, and a bit of Hazel but the Hollywood definitely feel that one. Yeah, so quite a lot of the radio tracking studies that have shown that Bechstein's love at one nice woodlands with love oak, but also nice dense Hazel understory, or understory in general, but particularly Hazel, and Holly, they do seem to prefer those type of habitats, I guess it just gives them this sort of structure on the woodland with a lot of well, possible food for them, because they don't want to forge too far from their roosting sites. So they need structure, different types of habitat within the woodland, they spend a lot of time high up in the canopy, they also come down and glean on the ground to feed. And actually, it's very handy in the UK because this understory is used sort of to catch them. So we put up often the heart traps under nice Hazel tree with a rule and the bats will sort of come down. And that's how we'll catch them. Actually, when we tell this to our colleagues on the continent, they think it's hilarious because they don't actually find Bechstein's that way, because it's impossible to catch. Back Stein's will hop traps, they just put hundreds of metres of Miss nets in the hope that they will get the odd back stones. But so definitely in the UK seems to be a key feature. But backsides are going to think about it like quite sort of widespread throughout all of Europe. And they will use other sort of types of woodlands. And we're what we think is perfect habitat for Bechstein's other people on the continent. Why just like, that's not where we find where we find our Bechstein's. But yeah, one key thing definitely seems to be a nice, old oak trees that that's definitely where they prefer.

Steve Roe: 29:58

We think we're about to maybe other teams or whatever. And then we're still flooded, and hopefully then we'll go and get some processing them with with the attendees colony. So Patrick was handsome enough on X, we've got a mask on. We've just had lunch. And we're nailing on blanket when explained what marinas doing with a boxer the minute Yes,

Patrick Wright: 30:18

so we just took the the box down from the tree. And we have the box covered now. And Marina is just about to open the box. And she's going to very carefully gently extract or the or the bats that are roosting inside. And we're going to put them in that box. And once that's all done, we'll be able to start processing the bats.

Steve Roe: 30:46

And what sort of biometric data are you gathering from them?

Patrick Wright: 30:50

So one of the first things we do is measure the form. So that gives us information on sort of the growth of individuals over the years. There's actually been a paper published on looking at how climate change and like hot years are impacting the size of the individuals. And then we're going to weigh them and look at sort of their ring number because we know which individuals which and And yeah, breeding status, and then I'll be damned on for the day we'll put them back in the box and hang them back up. Nice

Steve Roe: 31:30

Marina and Patrick and Sam and the rest of the crew just starting to press the bat. Jim is on again. You've moved post? Well, you've started a temporary post with PwC for the next few months, she just want to describe for, for people listening who don't know what bedtimes look like trying to describe a bedtime.

Jim Mullholland: 31:51

Well, where do I begin, I guess I'll start with the face in the years. So we all know that bats will navigate and hunt using echolocation to the signs they produce that sound gets sent out into the environment. And then they listen to the returning echo. And we have a few specialists who can either hunt passively, or switch off their echolocation, depending on what they're doing at the time and Bechstein's about so one of those they have these huge ears, either side of the head and often mistaken. With brown long eared bats. One of the key differences is that the ears have a clear separation through the middle. And they don't retract in the same way that brand login bats is do when they're at rest. They have a lovely kind of long dog like muzzle kind of pinkish face. Lovely white belly, Brian back. And I think that's all I got to say about well, they look like I think I've run out of characteristics, I

Steve Roe: 32:57

can talk about that. Quite a long Muslim, they look like Fox like, yeah,

Jim Mullholland: 33:02

we've got a mixture of adults and juveniles here. So we've got some that are kind of the typical orangey brain as you would expect in the adults. But as with a range of different bat species, the juvenile of the year look, typically slightly more grey, than the kind of brainy adults, I might step back, just so I can take the mask off as I'm talking, breath in.

Steve Roe: 33:28

And just describe how these guys have been fitting rings to these paths. And for people haven't seen bat rings before.

Jim Mullholland: 33:35

Yeah, so the bats are tricky to mark in this way. And we want to mark them. So when bats are recaptured in the future, we have a known history of the individual that we're dealing with. And there's all sorts of studies that can flow from that. So thinking about minimum ages or populations, that kind of the distribution within the population itself, you know, whether it's ageing, whether it's a young population, how successful certain bats are at breeding, and unlike birds, where the rings are fitted over the ankles, and they're fairly standard size, and my understanding is that they're fitted with pliers. So in every single ring, that's the same design gets fitted in pretty much exactly the same way. We don't have a free ankle to be able to fit rings on to bats. So we ended up putting them on the the forearm. And of course, on one side of the forearm, we have the wing membrane itself. And so we're not able to close the ring fully because if we were to do that, that would puncture and damage the wing membrane, which we want to avoid. And so we have an open ring. And so it slides on top of the forearm. And then it gets closed down to a size that we think is sufficiently small that it won't come back off the forearm. But equally, we need to be aware that we don't cause any damage to the forearm, or the wing membranes. And also that the finger bones don't get trapped within the ring itself either. So if you think about how bats move, typically roosting, they will be hung upside down. And so presumably the rings will be closer to the wrist. And when they're flying around, they will change in all sorts of different directions. So there's possibilities for the ring to move up and down the forearm itself. And because the wing retracts, that's when the the finger bones can potentially come into contact with the ring, which we want to avoid that entanglement basically. So it's a little bit of an art involved in this.

Steve Roe: 35:52

So this data has been collected for many, many years now, who's using the data and what gets done with it. People

Patrick Wright: 35:58

didn't actually know that when they started ringing back in 99, that this could be used for, you know, some random guys PhD in 2050. And so you never know what kind of opportunity may arise. So, I often see used some of this data for my PhD but then recently We've been collaborating with researchers at Exeter University, and they've been sort of analysing this dataset and extracting information on, for example, the lifespan of the bats. So we found that although we get some pretty old bats around 18 years old, what 18 is our oldest one, but actually most of them live five years, Max. Yeah, the lifespan is five to six years survive on the first year is very poor. So half of the bats that have fortunately we bring the first year, we're not going to, we're not going to see them, half of them being male, so we're not going to see them again. But actually, half of them also die. So we're going to actually going to see only a quarter of these baths next year. And then potentially, we'll look at the social networks see looking at how each, all these different individuals, how they connect, if they have like, preferred sort of relationships, individuals, or whether they tend to hang out with most, and so on. So it's a Yeah, the bigger the dataset gets, like, the more questions we'll end up with, and yeah, we'll just endless questions. I think this

Steve Roe: 37:24

guy's a process and the third box full of Epstein's. Patrick, you were talking about the difficulties of monitoring Epstein's nationwide? Why are they so difficult to study?

Patrick Wright: 37:38

Blackstone's they tend to sort of roost up high up in the trees, and they often split up in different groups. And they're performing. So this fish infusion behaviour. So, you know, for some of the species like the horseshoe bats, it's really easy, we can just go to a nice barn where the whole maternity colony is going to be in there easy access, and you can just do a count of the population. And you can do that many, many sites as many maternity colonies that you know have with back Stein's, first of all, it's not always easy to find a maternity colony. And then when you catch, for example, a female, if you want to find the roost, you actually have to put a tag on it, track them to the roost, whether there they are. And then if you do a count, it's not very easy to actually see the bats exiting. And the count might just be a very small represent representation of the actual colony. So that's just makes it super complicated. And so far, no one has really sort of knows how to monitor populations, nationally. So this is people are trying to do this in many countries. And everyone's still struggling for those sort of issues. And it's not just for backstage, it's also for the bass like barber sales, and so on. So yeah, back brackets, compass is kind of like the ideal situation where you just get all the bats in a box, and you can sort of get fed ID on the population and the trends. But one of the ways we're sort of exploring is to use genetics as a way to monitor population sizes. So with the tools that I mentioned earlier, we can look at the effective population size. So this gives us a fairly good idea of the population size of the breeding population surrounding words of the location where we are. So if this is sort of replicated at different sites, and also regularly, so maybe every five years, which is roughly the generation timer for of the species, we will be able to hopefully detect the population trends over a long period of time. But obviously, this is not easy to set up because of many, many limitations. But yeah, ideally, that's what's something we would like to tackle adventuring, like live trust is just getting a hold of population trends for these, these more elusive woodland species.

Steve Roe: 40:03

So you guys obviously been doing this a long time. There was a national back Stein's Monitoring Survey quite a few years ago, organised by obesity. Is there anybody else doing anything?

Patrick Wright: 40:14

Well, there's quite a few black boxes now black box schemes. So I think they'll someone will show some more endorse it. So there's a handful and Herefordshire as well. Then a lot of radio tracking by back group. So a lot, there's still a lot of interest in, in Blackstone's and sort of their ecology and sort of just local back groups wanting to understand more. But as far as I'm aware, I think sort of definitely some more areas of research that are needed to that we need to look into and yeah, I think other than the sort of the data tracking here and there that consultants and local back groups do I think there's a yeah, that's pretty much it for vaccines.

Steve Roe: 41:00

So it's getting told me it's gone five o'clock now. We're all really hot and exhausted. Why do you keep going back month after month? Why do you love it so much?

Patrick Wright: 41:08

I guess it's just the adrenaline and you never know what you're gonna get. But, ya know, it's just like, just fascinating to I just see all these bats and you always like starting to know the ring numbers. I think people like just getting used to having hearing j two one all day long. So the j two one or the bats that have been raised over the past two years. And so if we have another bat that starts ringing about us with a U or H people get quite excited. And oh, what year was that? So that's always quite exciting. So far, oldest bat is 14 years old. And what so we've done three boxes, and that's 70 plus 90 bats. And still probably 2030 more to go. And there'll be Yeah, for we will be done by six, six ish, I think it's just Yes, just always so exciting.

Steve Roe: 42:04

A huge thanks to the team at the Vincent Wildlife Trust and Dorset Wildlife Trust for having me along for the day. We've put a link in the show notes to the bat pages of the vents and Wildlife Trust. I hope you've enjoyed this first instalment of series five, please tell the world about Bat Chat on your social media channels. And we'll be back in two weeks time at a roost where bats emerge from the mouths of gargoyles see them