BatChat

A Churnet Chiroptera Conundrum

February 19, 2020 Bat Conservation Trust Season 1 Episode 9
BatChat
A Churnet Chiroptera Conundrum
Show Notes Transcript

S1E9 Steve heads to the Churnet valley in north Staffordshire to join Staffordshire Bat Group members Helen Ball and David Nixon for the day. Helen explains how a colony of Brandt's bats in one of their bat box schemes (started by the Vincent Wildlife Trust) have become one of the main study subjects in their small Myotis bat project which is taking place across the Churnet valley. In the evening, Dave explains the aims of the advanced bat survey techniques they're using out in the field to help with the study and discusses an interesting finding they've made where there appears to be no overlap between any Brandt's and Natterer's colonies within the valley woodlands.

If you're interested in finding out more about the bat work taking place in the Midlands region, the biennial Midlands Regional Bat Conference is taking place on Saturday 28th March 2020, more info and booking here: https://www.bats.org.uk/our-work/conferences-symposia/english-regional-bat-conferences/midlands-bat-conference

Take a look at the Staffordshire Bat Group website: http://www.staffordshirebats.btck.co.uk/
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Steve Roe:

This podcast episode is dedicated to the memory of Craig Slawson, who sadly passed away on the 11th of February 2020. Craig was the biological recorder for Staffordshire based at the Staffordshire Wildlife Trust within the ecological record centre. He was always incredibly helpful to staff to that group and kept their records in good order. None of their queries or requests were ever too much trouble for him. Craig will be missed by all of the wildlife recording groups across Staffordshire, the Peak District and the wider biological recording community of the West Midlands. Our thoughts are with his wife and family. Welcome to BatChat the podcast from the Bat Conservation Trust. Last October I joined Staffordshire bat group members Helen Ball and David Nixon to take part in the small Myotis bat project in the Churnet Valley. We started off the day checking one of their bat box schemes before heading out in the evening. I'm Steve Roe and this is BatChat. Helen what and where is the Churnet Valley?

Helen Ball:

Okay, so the churnet Valley is a really well wooded area of land in North Staffordshire. The upper stretches of the Churnet fall from the upland areas of North Staffordshire Moorlands and it flows in a southeast direction into the Dove and then into the Trent. And it's quite a notable area in the overall West Midlands. It's a second most wooded continuously wooded area in the West Midlands, so notable for its woodland cover, but also it's in a matrix of wet woodland, and there's unimproved grassland on the slopes. So a really nice sort of mix of mosaic of habitats.

Unknown:

And the woodland we're in now is called Consall Woods. What's so special about this woodland and why have we got so many bat boxes in this woodland.

Helen Ball:

So the Consall woods is part of the wider Churnet Valley SSSI woodland. This woodland is towards the centre of the Churnet Valley, and it was selected a few years ago as part of a Vincent Wildlife Trust project to look for the Northern Distribution of barbastelle. So the boxes 100 in total were put up in 2004 with Colin Morris. We didn't find barbastelle, but within just a few months of the box has been put up. They were colonised by a maternity colony of Brandt's bats, which used the boxes for a number of years. And that was very notable because the clusters went up to sort of 20/30 bats.

Unknown:

So what what is it that we reckon about this world and that makes it really good for the Brandt's colony then. So Consall woodland is in the heart really of the Churnet Valley SSSI It's a very extensive overall woodland area that is bisected by a river the river churnet but also a canal, the Cauldon canal that flows along the base of the valley alongside the river. There's also a railway line that runs along part of it as well and no roads. So the woodland is very undisturbed. There's a continuous cover. And it's a lovely mix of broadleaf woodland which is Oak Birch with a very good Holly Hazel understory. So there's a lovely mixture of broadleaf woodland, adjacent to river and canal and also interspersed with unimproved grasslands and the like. So we've just found a cluster of bats in a box, there's 13 bats in total, all Natterer's eight female, five male, the majority of them are adult. Many of the females are post lactating. And the males are in a variable state of breeding condition.

Steve Roe:

So what sort of roost would you say that is then?

Helen Ball:

Well, judging the time of year, the late, late in the season breeding time into October, I'd probably say it's a mating cluster of Natter's. And we've had one already have just checked the number of nine Natterer's earlier on so it's too mating groups so far.

Unknown:

And you say the bat boxes have been used by Brandt's in the past, are the Brandt's still here because the minute we've just found a load of Natterer's bats, which were just processed at the moment, are the Brandt's still around and did you say that was maternity colony as well. So over time, we've seen a change in the species composition using the boxes. So Brandt's utilise them very early on. And then over time we started to pick up Natterer's which are still using the boxes now. But the boxes have been colonised and particularly during the summer months and early spring months by large numbers of noctule. The noctules roost in individual numbers and small groups throughout spring and summer. And it's notable that since the noctules have colonised the boxes, the number of Myotis bats we're getting the small Myotis is reduced all the Myotis are roosting in a smaller number of boxes, although, when we come across the Myotis they're generally in good numbers per box. So why do you think the noctules have colonised? What's changed in the wording that's caused about species composition to change? Do we have any ideas why there might be? No we don't. And there aren't there hadn't been any management changes in the woodland at all. The Woodlands very recently been taken over by the RSPB. It was managed very well for a long time by Staffordshire county council. There's been no change in the woodland itself. The only thing we can think is that slowly over time noctules will have encountered the boxes found them to the favour to the point where they use them now extensively throughout the throughout much of the spring and summer. And for that reason, we're going to look at either removing some of the boxes or putting up a different style of box that may be more favourable to Myotis and less favourable to noctules because the ones currently up are all Schwegler 1FF boxes. And I know we're meeting Dave next and tonight who's running a small Myotis project is that projects looking at some of those reasons as well, what's the aims of that project. So the small Myotis project. One of the springboards for that was because of the brand's maternity risk that was found in this ward, and the fact that the Churnet Valley woodlands very extensive and under recorded overall for bats. So this the data from the bat box check are obviously going to tie in with Dave's small Myotis advanced trapping project. And in fact one of Dave's study sites is Consall woodland, Consall Nature Park And bat box schemes like this are run by bat groups across the country. What's the purpose of them in general other than by groups going out and using them to look at the species competition? And what are the other reasons of putting up bat boxes in woodlands? So yes, bat box schemes are brilliant because they provide long term data on the bats that use the boxes so we can look at species sex composition, age range. But the other great thing about bat box schemes is it allows volunteers that maybe you've never seen bats before or want to learn how to handle bats to get up close and personal with bats. Learn to take them out of boxes, learn to put them in boxes, and then slowly over time, build up the handling skills and get to see a range of bats that can be very active or quite deeply in torpor, and out in their natural habitat to to cause not like a sort of captive batterer grounded bat.

Steve Roe:

So it looks like they're finished putting the books away. So shall we move on and see check some of the other boxes?

Helen Ball:

Yes, yeah, let's get them finished.

Steve Roe:

So following an afternoon of checking the console would bat boxes, we're now headed for a site a little further down the Churnet Valley to carry out some advanced survey techniques with David Nixon. Dave, what are the aims of the project?

David Nixon:

Well we're interested and species assemblage throughout the Churnet Valley, and we're also interested in behavioural patterns of Myotis bats, particularly Brandt's, whiskered and Natterer's. Of course, like most bat groups, we're also really interested to know if Alcathoe is in the Churnet valley or in Staffordshire.

Unknown:

And what baseline survey for does this sit on what what previous survey what's been taken place on top of the So Consall nature park is in the Churnet Valley. And a number of years ago, the Vincent Wildlife Trust donated bat boxes with a view to see if barbastelle are in the Churnet Valley. Barbastelle were never discovered in the bat boxes. However, we did ascertain that the churnet Valley is a stronghold for Brandt's. And soon after the boxes were erected. Brandt's maternity roosts moved into the 1FF boxes which is really interesting. It's great new. So based on that plus, survey work using statics throughout the Churnet Valley. We came up with a small Myotis project.

Steve Roe:

What survey methods are you using to find out more about these bats?

Unknown:

So we're using Mist nets and also harp traps to catch bats as well. And good woodland where we know that Myotis are abundant. We're also using acoustic lures to try and bring the Bats as well into the nets and into the harp traps

Steve Roe:

And how many surveys have you done so far?

Unknown:

Yeah. So at the moment, we've carried out 12 surveys as to be expected. Consall nature park. RSPB Coombes are still definitely a stronghold for for Myotis. So we've discovered that we're not finding Brandt's in the same locations, as we find in whiskered and Natterer's, which has always been something that I'm particularly interested in. When initially, when we were when we started, when the boxes went up, and we got the brands, maternity roosts moving into the 1FFS over time, we've noticed that Natterer's are moving in and the Brandt's are disappearing. And that's showing in the results for the trapping projects as well. We're not getting Brandt's in the same locations, as Natterer's and whiskered. So aside from carrying on the surveys that you doing at the moment, what's the future aims of the project? Where do you see the project going from from where you are now? So tough question, because sometimes projects can sort of go off on a they can go off on a different route then you might expect, but we're still in the early stages of the project. We've still got a number of sites that we we haven't tracked but yeah, I'm I'm hoping I'm hoping that the project will stay will stay in line with with the original proposal, which is to try and establish a behavioural patterns between small Myotis I'm really interested in foraging. We all know how we all know that sorts of Brandt's favour, good quality woodland whiskered, more so associated with with fields and hedgerows and agricultural farmlands, etc. But we also know that they utilise similar habitats as well. So I'm not sure yeah, I'd like to I'm really interested in in movements of, of bats in in good quality woodlands, particularly those along the edge of the Peak District. Presumably at some point that'll inform future conservation action plans for the Churnet valley as well. Absolutely, yeah, yeah, it will do indeed. Yeah. Particularly with the with the stronghold of Myotis up here. Yeah, I'm not sure where that will go or what will happen moving forward. But yeah, it would be it would be good to, for it to inform.

Steve Roe:

And how important to volunteers to the project?

Unknown:

Yeah, absolutely. Very important. Indeed. Yeah. Yeah. We couldn't run the project without volunteers. We've got different levels of experience as well. We've got we've got volunteers who are capable of taking extracting Batchelor maisonettes volunteers helping to put hearts up. So volunteers who are even even volunteers who are scribing, it's all very, very important to us, we couldn't have done it without them. And in terms of using Mist nets and harp traps and acoustic lures, what are the challenges of that sort of survey method compared to more typical survey method. So using using Mist nets and harp traps and acoustic lures it's, there are a number of challenges. Mist nets can be quite difficult for bats to get bats out of to extract them safely. It can be difficult because on busy nights, it's hard to, to watch over other other assistants to make sure that things were running smooth. It can be it can be difficult at nighttime, we're working in woodlands, where there are trip hazards, and other people as well members of the public. So yes, it can be it can be challenging. But we have a good risk assessment that we adhere to. And we haven't had any any problems so far. And obviously you're tapping a lot of sites through the Churnet Valley, how many landowners are involved and do you find that landowners are pretty accepting the project are you finding it's quite difficult to get access to certain parts? We've had no problems. We've had no rejections from anybody who we've approached. We have Staffordshire wildlife trusts. We have the RSPB, Stoke on Trent city council, and Staffordshire county council. And also we do have permission to trap on some private, private land as well. Everybody's been supportive. Everybody knows it's for a good cause. It's all in the name of bat conservation and to try and better our understanding of of bats that can be quite difficult to to identify using sonogram analysis alone. And obviously, there's long way to go before you start publishing results of this but are you going to publish those results of the project anyway, where should people look out for in a few years once you've started collating the results of the project. Absolutely, yeah, yeah, no, it's...in my eyes it's really important for for the data to be published. It will go to the record centres of course, it's going to go out to all those involved. So Suffolk County Council, the RSPB, etc. will also publish on the Bank Group's website, the staff at your Bank Group's website. And we're hoping to do a talk at the Midlands regional conference as well, which would be really good. Great stuff sounds like a really good project. Dave. Next and thank you very much.

David Nixon:

Yeah. My pleasure. Thank you.

Unknown:

Having caught up with Dave recently, he's told me that there have now been 24 surveys over the last two years. There's still no evidence of Alcathoe's within the Churnet Valley yet and Brandt'd and Natterer's bats are still not being caught in the same areas of woodland, which remains a surprise. Dave and Helen hypothesise that as the two species utilise different ecological niches, they can't imagine that Natterer's naturals are exclusively excluding Brandt's from particular areas of woodland. Although they suspect that Natterer's might oust Brandt's from the bat boxes the same way that noctules can come to dominate. They suspect that over time, their data will show that Natterer's will tend to be caught towards the outer edges of the areas of woodland that they're trapping in, whilst Brandt's are more likely to be found deep within the woodlands, and they hope that the study will help to add to our understanding of small Myotis bats, and how the Brandt's colony at Consall might be conserved in the long term. If you're looking forward to the next episode of BatChat, be sure to hit that subscribe button so that the next episode will automatically land on your phone when it's available. Next time we're discovering what life is like as an island back group with the Isles of Scilly and the Channel Island bat groups.