The National Bat Monitoring Programme

S3E33 Discover the amazing work taking place in the dead of night each year by hoards of volunteers. This episode starts with Steve joining a team of these volunteers who are counting out a brown long-eared bat roost in the Derbyshire Dales at dusk as a nearby rookery gathers. We then sit down in Battersea Park, London with Philip Briggs, monitoring manager for the Bat Conservation Trust who collates all of this data sent in by volunteers and turns it into invaluable trends to establish how our bats are faring year on year in the UK.  The National Bat Monitoring Programme is one of the longest running citizen science projects in the world and YOU, yes YOU can take part! There are surveys which need no prior experience.

• Get involved with the NBMP yourself here
• Take a look at the summary maps for each survey type
• Watch footage of the brown long-eared roost being counted out by Jill in this episode here as the bats return at dawn
• Read the latest NBMP report to see how our bats are faring
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Producer: Steve Roe @SteveRoeBatMan
Cover Art: Rachel Hudson http://rachelhudsonillustration.com/

Transcript

Steve Roe: 0:12

Hello, and welcome to BatChat. This is the podcast where we bring you the stories from the world of Bat Conservation. We're continuing series three with a couple of guests this week. If you're a regular listener of the show, it's great to have you back with us. And if this is your first time in joining us welcome along. episodes in this series are being released every second Wednesday. And this is the penultimate episode of Series Three. And you can join the conversation online using the hashtag bats chat. So that's all one word. As we meet each of our guests in this series, you'll hear from people working to make a difference in the world of bat conservation, people who care about individual species, people who concentrate on one particular part of bat ecology, and people who are working with bats at a landscape scale, as well as keeping up with the latest news and hearing from people in the world of bats. We hope that you'll be inspired to get involved because bats need our help. I'm Steve Roe, a trustee of the Bat Conservation Trust. I've been involved in bat conservation for over two decades. And in that time, I've come to learn that there are some really great projects and stories out there. One of the best known projects in the world of bats and indeed mammals is the national bats monitoring programme or NBMP. To start us off, we joined Jill Leheup from Derbyshire bat group who was in the middle of undertaking rousse counts for the NBMP and she explains what she's up to as dusk falls in the Derbyshire Dales. So Jill. How long have you been doing that work?

Jill Leheup: 2:01

So long, I don't think I can remember. I got involved in the Start through a colleague at work. We both work for the Derbyshire Wildlife Trust. And Sue wanted to go along to be come a volunteer bat roost visitor, and asked me to go along with her. So I said I would not really know what I was letting myself in for to be honest. Anyway, I passed the training, and then started doing bat roost visits and talking to people and I suppose that's the thing that I've really liked doing talking to householders about that.

Steve Roe: 2:40

So what's the roost we're counting tonight?

Jill Leheup: 2:43

It's a BLE a brown long-eared roost. A lot of other bats around to confuse matters and go for that one. And we're counting it for the roost count for the national bat monitoring programme. And trying to see if the number of bats roosting here is stable from year to year. I mustn't click the next one because I've already clicked one too many.

Steve Roe: 3:13

How many bats is there normally in this roost?

Jill Leheup: 3:18

There's normally getting on for 200 not counting that one. At the moment, I've counted five, but they do come out from all over the place. I'm not expecting to count all of them myself.

Steve Roe: 3:31

Yeah, I was gonna say we've got four other volunteers here tonight and it's quite a nice mild evening and rooks have just gone back to copse of trees over and over the other side of the house.

Unknown: 3:43

And you're right Steve it's mild. There's a lot of insects around a lot of bat bait around. Here are the things for us bats to the bats to me.

Steve Roe: 3:53

What's the detector you're using there?

Unknown: 3:55

It's magenta bat five, which I like because it's got a big digital display, which people with failing eyesight can read. Good for anybody. Good for anybody.

Steve Roe: 4:13

So how many of these roost counts you normally get involved with during the summer then?

Unknown: 4:17

The roost counts I do well, including this one, three. I do one in Cromford. That's a soprano pipistrelle roost, and it's got over 200 bats in it on the two counts that we've done this year. There's one in Matlock Bath that it's got about 150 bats again, it's a soprano roost. And what I found quite interesting was that the Cromford one, there's only one place that the bats come out of, and it took a good hour for the bats to come out. Yeah. Whereas the Matlock Bath one it seems to be quite a leaky roof and there was probably five places that they were coming out it was all over in half an hour. Hooray! Cup of tea off to bed so yeah it was quite quite interesting how they all yeah them in the must be lining up in there ready to come out when there's only one exit tricky that second one I suppose it did so the rooks have gathered and now moved off to somewhere else, the night roost I guess. Trust my eyesight now.

Steve Roe: 6:40

So, that was Jill undertaking a roost count and at the end of the night, the five of us collated our our counts, and we had 191 Brown on good bats emerge from that house last summer, which is a pretty average count for that roost. That data collected by Jill was then uploaded to the NBMP website where it was received by the team at the Bat Conservation Trust, which is led by Philip Briggs, who we hear from next, I sat down with Phil in the autumn just over the road from the BCT offices in London, Battersea Park. And amongst the sound of parakeets and waterfowl on the pond, he gives us an insight into what the NBMP does for about conservation. It's a breezy autumn day, nice sunny morning, and I've sat in grassy park next to a lake with a load of pigeons and various wading birds. And I'm sat with Phil brakes from the Bat Conservation Trust. Phil, do you just want to introduce yourself to listeners and say what your job title is and what you do at the trust? Yeah,

Philip Briggs: 7:34

I'm the monitoring manager at the Bat Conservation Trust, which mainly involves project managing the national bat monitoring programme, but also other bat monitoring projects that we take on.

Steve Roe: 7:46

And I mean, how did you get involved in that? And have you always worked on the NBMP since starting at BCT?

Unknown: 7:52

Yeah, well, I've been interested in wildlife from an early age. And I remember when I was in my teens, standing by my local ponds, watching bats flying around, and just thinking how amazing they are. And I remember thinking to myself, I wonder how you tell them apart. And if someone had come along and told me, that'd be my job one day, I just wouldn't believe them. But then I started volunteering at the WWT London wetland centre. And then about 20 years ago, I went to my first bat walk, and just was immediately hooked. And I ordered a bat detector. And a good friend of mine, Richard Bullock, who was his ecologist at the science, he said, Well, you've got a bat detector, you should get involved, the bat walks the bat surveys. So I started doing that. And then a couple of years later, I started taking part in the National Bat Monitoring Programme, doing the field surveying waterway survey. And then later, at the end of the summer, the opportunity came up to apply for the role of survey coordinator. So I applied for that, and successful, which was really exciting. I've been working in publishing up to them. So it's a real career change. And I hadn't even really thought of a career in wildlife conservation, even though I was really passionate about it. So it just really fell into place. So I started off as the survey coordinator, think about four or five years later, I applied for the role of project manager and got that role. And that's just kind of evolved over the years and is now the monitoring manager. So it's now about 18 years that I've been in working on the Bat Conservation Trust and all that time. It's been on the national debt monitoring programme, so I do kind of feel like I found my vacation.

Steve Roe: 9:37

Gonna say you must know it inside out by now. I have no idea in publishing what may what was the career change?

Unknown: 9:42

Yeah. Well, it's funny, I did an English degree, so I'm not a scientist at all. So it felt well, I went into some bibliographic work for a bibliographic agency for about five years. But all this time I was volunteering, doing wildlife conservation volunteering, so you know If, in a way, it was like a sort of logical change, but it wasn't really one that I particularly plans, you know, sort of one, the opportunity came up and I just went for it really.

Steve Roe: 10:10

So I mean, I'm here to quiz you about the NBMP. So for anyone out there who doesn't know what it is, can you give us, you know, give us the elevator pitch?

Unknown: 10:13

Well, it's really about discovery, I think discovering bats near where you live, and really kind of helping us monitor how bat populations are faring across UK. That's a really important thing to do. But it's also really fun and rewarding thing to do. And we have surveys, suitable for all levels of experience. So including complete beginners, so you don't have to have any previous experience to take part in, in one of our surveys, right up to licenced surveyors in putting hibernation surveys, or can get involved with our tracking projects. So there's really a kind of amazing range of different ways people can get involved. And that was gonna say, you mentioned the different surveys, can you just tell us a little bit about each of those different survey types. Okay, so we have our beginner level survey, that's the sunset survey. And you don't need any previous experience, you don't need any equipments. You don't need a bat detector. If you've got one, you should use one, obviously. But it's designed so that you can actually record what that see see, or whether you see some bats and other nocturnal wildlife, just by using visual clues. And then we've got the roof counts. So you need to know of a roof that you can monitor. Quite often it's householders who've got bats in their property who are doing the counts, or it's kind of bat group members or other bat enthusiuasts. So you've discovered that roost in the local area. And this simply involves standing outside the roost at dusk, usually in June for most species in June, and just counting about cells to see emerge. And then we've got to bat detector surveys, which involve walks transects, the field survey, where you're monitoring for species common pipistrelles, soprano pipistrelles, noctule and serotine are then in Northern Ireland, we ask people to monitor Leisler's bats instead of noctule and serotine, just simply because of the difference, bats that they get over there. And then we've got the waterway survey, which is also walking along a one kilometre stretch of waterway monitoring depends on stats. And then in the wintertime, we collect data from hibernation sites. So these will be sites that are monitored often by back groups or other licenced stat workers who are kindly sharing the data with us. And there's a few other smaller projects. But those are the the core surveys, which we which we really get very high engagement in, which of those is your favourites. I'm particularly fond of the back to Sector transect surveys, I do like going out, seeing, you know, walking these routes, and I get very familiar with my routes, as well get very, very familiar with the site's re attached to them. I don't even need to look at the route map anymore. So I'm so familiar with them. And actually, when I'm first doing one of these sites, I love looking at the map and just thinking of what am I going to find in all these different places. And so what I like is sometimes, well, you often find bats at the same spots each time. So some spots are really reliable areas for bat activity. But then bats will turn up at more unexpected places. Sometimes there's a spot where I think I'll have to send it for two minutes, and I never get any bats here. And then just as I'm telling my survey buddies, this a bat will fly past. So I think long by transects, probably bats have turned up at most of the recording locations over the years. But there's a few where they will always always reliably turn up. And I even have one, one transects, which is right near where I live, it's just involves walking around suburban streets. And my expectations aren't always very high, because sometimes I don't get any bats. So I sort of challots and manage my expectations. They're just my, you know, sort of, you know, sort of threshold and what I think is a good result. And if I get one that I think are great, I've got one that's in the survey, I've got the results. But all the sites are really important regardless of if you get one bats or no bats or lots of bats. This is all really important data, because it's feed into a much larger data.

Steve Roe: 14:21

Exactly. Yeah. You joined 18 years ago, where did the idea come from? You know, what's the history of the programme?

Unknown: 14:29

Well, it started in 1996. So that was about seven years before I joined BCT. And it was originally commissioned by the Department of Environment transport some regions. So BCT were commissioned to set up a effective programme for monitoring bat populations across the UK. And they've been there's sort of bits of evidence that that numbers have really declined over the previous 50 to 100 years or longer. So data from specific sites such as hibernacula that have been monitored for many years, species undergoing range contractions such as the horseshoe bats, we know their their range contracted quite significantly. Historically, lots of lots of anecdotal evidence so things you're reading books, you know, ceramic total evidence about, you know, seeing lots and lots of bats in certain locations where we don't see lots of bats nowadays. So there was quite compelling evidence that bat numbers had really declined. And we knew some of the real factors like timber treatments had really been devastating to to bats, roosting and buildings where timber treatments had been applied. So there was a real need to get much more kind of concrete evidence, much more kind of robust data and long term data, kind of geographically widespread data on how bats are faring. So that's, that's why the programme was set up. And it was really the perfect time. Because up until then, the technology to bat detectors had really been not very accessible to volunteers. If you've seen David Attenborough his life on Earth is a bit where he shows a bat detector, a great big unwieldy thing, prob, probably cost a fortune. So bat detectors have become very much smaller, much more affordable. So they're now in the hands of volunteers. And also round about 1990. They'd been the setting up for the bat groups across the UK. So there's a real growing network of that volunteers. So it was perfect timing really, the time is really right to start doing a national bat monitoring programme.

Steve Roe: 16:36

And I mean, Have we got any idea how many volunteers have been involved in the programme over all those different years?

Unknown: 16:42

Yes. So since the programme began, we've had just under 5000, individual volunteers submitting data Wow. And this is us counting the volunteers who submit the data. And if you include their survey buddies, then it's going to be well over 10,000 volunteers who've been been taking part over the years. And we really just couldn't do this. Without volunteers, it would just be impossible. If we hired people to do that the costs will be astronomical, it would just be totally unfeasible. So we're completely dependent on volunteers. And it's thanks to volunteers that were able to track how that species are faring.

Steve Roe: 17:21

Now, all that species that we put in the UK are included in the surveys, Why have you chosen these particular species to monitor?

Unknown: 17:29

Well, it's all down to which species can be effectively monitored by volunteers. So the survey methods, they must be easily carried out by a large range of volunteers. So they can't be invasive techniques, they can't be techniques that require licences, they need to be techniques that are reasonably simple while still being robust. So for example, the risk counts, and that will be mainly species which are commonly found at buildings. So obviously, the majority of UK species use trees to a large extent. But tree roofs are very difficult to locate, it's very difficult to monitor for that. So these switching between roosts on a very regular basis. So it's mainly buildings that are monitored for roost counts. And therefore, it's mainly species that are largely found in buildings that are that are monitored. And then for the field, and the waterway survey is species that can be identified relatively easily and confidently with a bat detector. So there are five species that that we focus on for those surveys. And then, of course, we collect data from the winter hibernation surveys. And that kind of fills in small gaps in terms of species coverage, also gives us complimentary trends for some of the species you monitor in the summertime. But again, some species are very rarely encountered at these large hibernation sites, which we can actually walk into and see the bats. And some species are obviously very difficult to separate as well. So we currently produce trends for 11 species, which means there are six species we don't currently produce trends for. But we are developing methods for for kind of monitoring some more of these species.

Steve Roe: 19:14

Oh, tell us more. Go on.

Unknown: 19:15

Okay, so one key method is passive acoustic monitoring. So rather than walking around, identifying bats in the traditional way, using a headstone, bat detector, which is obviously very time intensive, and there's a limit to how much monitoring you can ask a volunteer to do at each sites. But obviously, it's quite a powerful method when you've got loads of sites across the UK over a long time. But there are still these limitations to what you can do with passive acoustic monitoring, you're just putting out a static back detector in a location leaving his house over potentially several nights. I mean, potentially, it could be weeks or even months. So it's collecting data throughout the nights, every night that it's out, triggering recordings when a bat flies past. And that way you're collecting huge amounts of data. And we, there are a number of automated classifiers, which are valuable in that they can help us process huge amounts of data, which we've completely impossible to look at, manually. I mean, with our pilot projects, we've been looking at something like cover up is certainly terabytes of data as of 35 terabytes of data or something like that. So it's huge quantities of data to work through the limitation of classifiers is that they can't actually identify every species to a high level of confidence. But there are certain species where we can certainly get get reasonably reliable results. So what we'll be able to get from passive acoustic monitoring is sort of complimentary data on the species we already monitor. But also data on some additional species. So we're thinking species that can be readily identifies that we'll be able to add to things like barbastelle, Leisler's bats, we'll be able to collect more data on things like horseshoe bats, potentially serotine. Although I must admit, I always often struggle with serotine classifiers often struggle with a bit as well. So quite often, I think, yeah, there might be a bit more checks needed on on results when you're looking at things like serotine, but certainly not to realise this, but you'll get more data on when they're producing them or more characteristic calls. The really, you know, the sort of Holy Grail is being able to separate the Myotis species, which are really challenging. But certainly Natterer's bats, their calls can be pretty distinctive. So you might be able to get some quite robust data, and that was bats. The other species, I think, remains to be seen how how reliable classifiers will get at this, I know, some people, you know, are pretty sure that certain classifiers are doing this quite well now, but I think we need a bit more evidence. So that that's, that's doing it. So we'll be looking at other techniques for the motor species such as, you know, DNA amount of system droppings, and that kind of thing. So, and maybe sort of looking at sort of more types of targeted trapping surveys for the species carried out by licenced volunteers.

Steve Roe: 22:16

And in terms of those passive acoustic surveys, are BCT, getting funding together to provide those recorders are we expecting volunteers who have access to one of those to use their own,

Unknown: 22:27

I expect it will be a bit of both. So we do have quite a large number of audio moths. These are the cheapest, smallest, passive acoustic recording devices. So they really are very, you know, kind of a bit of a game changer in terms of being able to do this on a wide scale. But I think we need to sort of really, you know, the protocols are still being worked on. So we need to decide, are we just going to be using one kind of detector or let people use any kind of detector that will do passive acoustic monitoring? Yeah. And also exploring potential remote sensing. So there's been an amazing project in the Olympic Park using, they've installed static detectors, which are the solar power. I know they're not I think they're running off the power from lamps, I think, I think that's right. And they're actually sending the data via Wi Fi. So they're completely unattended. And that's pretty much probably the, you know, having a series of those around the UK might be the sort of ideal method, perhaps during Yeah, but probably complemented by people actually putting out their own detectors as well. But, you know, having a large number of permanent monitoring stations would be fantastic, I think. But these are all things that we're kind of looking into. Yeah, we'll see what the next few years show for this year where we're running a small survey called Nightwatch, which is much more about just engaging people, sending them audiomoths off to put in their own gardens. Because we found that that's a real motivation for people to take part, people really want to know what's in their backyards, or in their local area. Perhaps that's much more motivational to some people then think given a randomly allocated square, which is better for robust monitoring. So this is kind of a separate passive acoustic monitoring programme, which is all about engaging people, particularly urban audiences, underrepresented audiences, people who, who haven't been so good at reaching out to a thing and engaging

Steve Roe: 24:40

So volunteers go out and have great fun and collect all their survey data, how once they've then sent you their data, how do you translate those results in statistical trends, which were then able to tell us how that populations are faring.

Unknown: 24:52

Okay. Well, process is quite simple for us. We send it to our statistician Steve that's So simple answer, as Steve has been involved in the NBMP right from the start. And yeah, he's he's a brilliant statistician. So he does great work on the trends and all sorts of other statistical projects. So Steve uses generalised additive models, which produces smooth trends. And this approach is quite robust against random variation between years. So if you get one quite anomalous year, it's going to get smoothed out. So not going to suddenly show that back to Sunday, numbers are suddenly shot up or suddenly declined quite dramatically. A real key components of the analysis is the looking at covariates that might influence the number of bats that are recorded. So we ask volunteers to record things like the weather conditions, the temperature, what kind of bat detectors, they're using all these sorts of things. Because these are all things which will can have an influence on the number of bats you record. So obviously, weather conditions, that's that's an obvious one temperature. But back detector is really important because different models of architects have different microphones, which have different frequency responses. So one detector might detect a certain species from from a greater distance than another detector. So that's gonna have a bit of an influence on how many bats are recorded. And then Steve analyses these covariates to see which ones are having a statistically significant influence. And then he can adjust the trends to minimise these biases. But in fact, some of the the results from this are interesting in themselves. So for example, we started looking at metaphysis data in relation to the hibernation survey data. So looking at minimum temperatures in the days leading up to the survey. So obviously, the volunteers will collect record the temperature on the day of the survey. But what we found was that the temperature at the minimum temperature up to three days before the hibernation counts, was statistically significant for certain species. And this seems to indicate that there is a bit of a lag in fats responding to changes in temperature while they're in torpor. So it turns out that temperature a few days before is actually a really important thing to factor in, because that has quite a big influence on how many bats you record on the day,

Steve Roe: 27:20

You've gotta love stats to be able to do it that much haven't you! And what's the picture so far? You know, how are our bat populations doing?

Unknown: 27:28

Well, there are some encouraging signs, so a few species are showing increases. So for example, the greater horseshoe bats and lesser horseshoe bats, which is brilliant news, because as we know, they underwent huge range contractions historically. And I think it really shows the the value and effectiveness of very intensive conservation actions. So there are a number of major routes which are very well protected and have been enhanced and modified and for the bats, and also landscape scale work. So the landscape around the roots. Interestingly enough, though, there is some evidence that horseshoe bats might be benefiting from the milder winters, which might kind of enhance the overwinter survival. And I know they are quite can be quite active in the winter, so they might get quite good, still get get some quite good foraging in milder winters. Also, common pipistrelle is showing quite a strong increase. And I guess, because it's a more adaptable species, that might be one reason why it kind of responses quite rapidly, perhaps, to any conservation measures. But it's quite interesting when you compare it to the soprano, pipistrelle, which is more of a habitat specialists search showing a slight increase, but not the sort of more obvious increase of the common pipistrelle. So there does seem to be quite a sort of logical reason to me why why you'd see that difference between the two species. But the challenge is really that there are some species where we just don't have data to be able to tell how they're doing. And most of these are real habitat specialists. So woodlands, habitat specialists, or kind of unimproved grassland specialists like the grey long had bats. And when you got habitat specialists, these are obviously the most vulnerable species. So, you know, that is that is a gap in our monitoring, which we're looking to address through these these additional survey techniques where we're looking at developing.

Steve Roe: 29:29

So you've just had it varies between species. Does it vary between regions, you're able to tell that from the data?

Unknown: 29:35

Yes, so to some extent, we're able to see this. We produce country level trends, where we have good enough sample sizes. We don't have good sample sizes for all species at the country level but where we can we produce these separate country level trends, and you do see slight differences between them. In our latest results for brown long-eared bats from the hibernation survey We can see there are slight differences between countries. So in England's I mean, it's kind of a stable trend, I mean, there's a bit of a downward slope. So the currents value is below the below the baseline figure. But because of the confidence intervals, we're it's not actually a statistically significant decline for carried on doing that for some more years it might be but things do fluctuate so well, we'll see what happens. Scotland's looks a bit more stable. But then interesting for Wales, there's a slight significant increase. So we're seeing slightly different patterns between between these countries. And it really shows the importance of being able to look at country differences and regional differences. Because a positive trend at the UK level might not necessarily be the case at country or regional level. So it's really important that we can see these differences. And that makes it so important that we can enlist more and more volunteers, because the more volunteers, then the more site's being monitored. And the more we can actually do these more kind of regional level breakdowns.

Steve Roe: 31:04

Can you tell us about some of the notable roosts or sites which are surveyed each year? And do you have any favourites where you look forward to receiving the data from volunteers,

Unknown: 31:12

there's one really remarkable site which will be lucky to be invited along to so it's the biggest bat roost in the UK. Not only is it the biggest bat roost, but it contains one of our biggest bats. And one of our rare respects as well, the greater horseshoe bats. So typically has well over 2000. Bats counted in the, in the NBMP recording period. So obviously, once the young are born, that's going to go up even more. But it was an amazing experience helping with account then, when you think over 2000 bats and their great big hefty greater horseshoe. That's, that's definitely the biggest volume of bats. I've been anywhere near in my life. And so we had three of us, I think a few of us by each respects it all doing our best to count these bats and merging all arms with tally counters. And I must admit, I'd find myself doing okay, lots of bats came out at that point. So I did lots of clicks on my tally counter. I'm not quite sure how they relate to each other. But you know, but there's the best I could do. At the end, the three of us who accounts that exits, two of us said moderately similar counts, the third person was way out. So we assume the two of us is moderately similar counts, it was a good ballpark figure. But yeah, that's just an incredible roost, you know. And so it's, you know, we're always quite excited to see what the counters like each year when it comes in.

Steve Roe: 32:34

And what would you say to those volunteers who go to their roosts, and they've got actually quite small numbers about us and the thinking now, there's no point in doing this yearafter year?

Unknown: 32:41

It's really important to think all that all the data are really important. And one thing we're finding is that what quite often happens is that when people start monitoring a release, there are lots of bats, because that's when people tend to notice the bats. And then quite often the roost might split. Or the bats might go to one that there are other risks for whales. So the numbers can can drop off a bit even go down to zero for a while. And then people think that bats have gone, they stopped counting. But it's actually really important to keep monitoring the roost, because when we've seen this pattern when the roost commonage tends to be monitored, the bats often do come back. So it does create a bit of a bias in the roost monitoring. If you know we're finishing the data series with a zero count. So it's really important to continue monitoring, keep going back each year.

Steve Roe: 33:33

So just the data and the results help influence government policy and legislation was in quite hard to get them to take notice of it.

Unknown: 33:40

Well, certainly, you know, taking getting governments to take notice is obviously obviously a challenging thing. But the trends are government's official statistics, which gives them obviously quite a high level of importance in terms of data presented to the governments. And every year, we need to send a briefing to Defra 24 hours before the statistics are published. So DEFRA do read them. I have actually seen a minister at the conference hold up our state of the UK's bats and quotes from it. So that was nice. So that was a nice thing to see. We also produce a bat indicator, which is an overall trends combining a range of different species. And this is part of the UK biodiversity indicators, which are use used by the government to report against biodiversity obligations. And then finally, our data used by the country agencies to do constituent assessments for SSSI, SAC sites, and also to assess new sites that might qualify for SSSI status. So yeah, there is they certainly do get used by governments and government agencies. Obviously, you know, we lobby a lot for policy change. Isn't that sort of thing and NBMP data are a real kind of part of our, you know, sort of, I guess, weaponry for that. But yeah, you know, that's often the challenge.

Steve Roe: 35:12

And early on, you mentioned, you've looked at how the trends of different species are doing against the baseline. Yeah. Well, I mean, it's difficult to say, because we don't have that historic data. But do we think about populations are, where they need to be? Or are they much further reduced than what they used to be historically? I know that's a difficult question to answer.

Unknown: 35:30

Yeah. Well, I think, you know, there's certainly quite compelling evidence that, that numbers were much higher, say, 100 years ago, or more. And what we tend to say is, we see these increases. And we say, you know, it's, this is evidence that these facts are showing recoveries after long term declines. But we feel, it's likely that these numbers are much lower than they were in the past. And then some species aren't showing increases. So for example, dependence, bats is showing a very stable trends, which is obviously, you know, the least you could hope for, but it's not showing signs of recovery. And so, sort of quite a, you know, to like a personal bit of bit of anecdotal evidence, which struck a personal chord with me was I was reading Gilbert White's natural history of Selborne. And he actually talks about actually went outside his, the county of Hampshire and went on a boat ride along the Thames in Richmond where I live. Yeah. And he talks about the huge numbers of bats he saw. And it's still a pretty good sight of bats. But it sounds like you're seeing way more bats than I do nowadays. So yeah, you know, it's just these bits of evidence, we think, are you there must be much more bats around there. And there's another bit of writing, which mentioned swarms of bats around St. Paul's Cathedral, which you just don't see now. So, you know, there's all these bits of evidence, which show that you know, if you went back inside and just be seeing vast numbers of facts, but a really exciting developments, is that genetic studies are revealing kind of, sort of information about past population changes. So this is something we're really keen to explore a lot more, because this could really reveal a lot about kind of changes in different species populations over the years, and maybe give some much more kind of concrete evidence about the sort of level of declines over years. So that's quite an exciting new developments, I think.

Steve Roe: 37:28

So you made these reports public each year, where can people get hold of the latest reports and maps?

Unknown: 37:33

This is all on our website. So if you go to bats.org.uk, click on our work, National Bat Monitoring Programme, you find the latest results, and all sorts of information about how to get involved information about the different surveys, training, online resources, I was gonna say people can sign up online, it's really easy. Yeah, that's right. Yeah, and we've got online recording as well. So you can activate an online recording accounts, submit your data online. And then you can see summaries of all the data you've submitted in the past, download all your raw data. So it's quite a nice system, as well as submitting your data, you actually keep ownership of your data as well.

Steve Roe: 38:15

When I was researching questions for this podcast on the train down there, I was looking at the maps. And when there's only one roost count for Brandt's, bats in the whole UK!

Unknown: 38:23

Yeah, there are some species where you have very small numbers of routes being monitored. And that's always going to be challenging for certain species where they're not found buildings so often. But it's good to have these all because it's all really useful data. And even if we can't produce species population trends, because we don't have good enough, good enough sample size, if the volunteer is ticks and box saying they're happy for this, then the data will go on to the NBN Atlas. So that can be really valuable for informing example, local planning, or research or whatever. So all the data we get, you know, will have at least one use will have no doubt have multiple uses, you know, over time, including, you know, being included PhD research, research projects, which kind of discover valuable new information about that populations. So, yeah, it's the producing trends as a core use of the data. But, you know, we get so much more value out of it when that

Steve Roe: 39:21

Phil Briggs it's been great having you on the show, thank you very much. You're welcome. A big thanks to both Jill and Philip for coming on the show. That's almost it for this week. I really hope you've enjoyed it. If you take a look at the show notes, you'll find links to more information about the national back monitoring programme, and how you can get involved yourself this summer. As Phillip said, there are surveys on there that you need no prior experience to take part. As you'll hopefully now know we are rolling back chats first ever competition during this series. children's authors Emma Reynolds and Angela Mills have kindly donated copies of their books about bats. Angela has donated a copy of Bobby the brown long-eared bat signed by both Angela and Chris Packham and Emma has donated a copy of her newly released book, Amara and the bats. To enter the competition to win one of these brilliant books. All you have to do is write us a review about this podcast about chat, and the two winners will be picked at random at the end of this series. Not all podcast apps play to leave reviews, so you can find instructions in the show notes of this episode. And please note that we're only able to post the prizes to addresses in the United Kingdom. Thank you. If you're one of those listeners who has left us a review we really do enjoy reading the comments you leavers. The series concludes in two weeks time on the Knepp rewilding estate thanks for listening