November 1, 2023 • 41 mins
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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.
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Steve Roe (00:03):
Welcome back to BatChat, the award winning
podcast from the BatConservation Trust for anyone
with a fascination in theseamazing nocturnal creatures. I'm
Steve Roe, and this is BatChatseries five.
Yes, hello, we are back with abrand new series and episodes
(00:25):
will be released every otherWednesday from now until spring
next year. If you're new toBatChat, welcome along. I'm
Steve Roe. I'm an ecologist andin 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 andenvironmental management, who
named us as the winner of theNGO Impact Award 2023 for making
(00:47):
a significant difference to theconservation of the natural
environment, as well as spendingthis year recording
conversations for this newseries. We're also really
grateful for those of you whocompleted our listener survey at
the end of the last series.
We've spent the summer goingthrough those suggestions, and
we'll be implementing as many aswe can over the coming series.
(01:09):
One of those suggestions was tohave more species specific
episodes and so here we are anepisode all about the
Bechstein's bats. This episodecomes to you from a Dorset
woodland. It's a place I visitedseveral times for over a decade
and the approach involvesdriving through a narrow dorsal
lanes with lovely tall hedgerowsVISTAs appearing where you can
follow the hedges across thelandscape, forming the
(01:30):
boundaries of small fieldparcels. Meeting staff of the
Vinson Wildlife Trust and DorsetWildlife Trust at the entrance
to the woods. This conversationstarts as the team begins to
check the bat boxes spreadthroughout this reserve.
So it's the middle of August andI'm in one of my favourite
places in the world to come andsee bats on down in the depths
(01:51):
of Dorset and Steve Masters fromDorset Wildlife Trust is going
to tell us where we are and abit about what we're doing today
in the woodland and why the WestWoodland is so special.
Steve Masters (02:02):
Yeah, so we are in the darkest depths of West
Dorset brackets coppice so thesite here Dorset Wildlife Trust
data reserves 45 hectares it's amixture of a lot of different
habitats from semi naturalwoodland. It's on the ancient
woodland inventory, which iswhere we're stood now to neutral
meadows, unimproved. We've got ariver that runs through the
(02:26):
middle, as well as also somewood pasture. Trust has been
involved here since about 1964.
So that's the Wildlife Trust.
And we took on the main block ofthe woods in 1987. And then
since then, we've acquired otherparts of the wood with the last
bit been acquired at 2002. Andtoday we're out checking the bat
(02:47):
boxes, which were put up in1998. I think the first ones by
Dorset bat group, and a ladythat was very involved with that
was a lady called Maureen Keats.
And she was also very involvedin brackets caucus and she loved
reserved and since then VWTVincent Wildlife Trust have put
up more bat boxes. And we're outchecking for the maternity
(03:09):
colony of Epstein's
Steve Roe (03:13):
and the woodland is saying some woodlands like we're
looking, we're stood in just offthe footpath and it's quite
difficult to see very farthrough the woodlands. So if I
can see the next day long afterthat it's quite a enclosed
understory, isn't it? How old dowe think the woodlands is Have
we got any idea at all?
Steve Masters (03:30):
Well, if it's on to Part of it's on the ancient
woodland inventory, which Ithink means it's at least been
around since 1600. But thelikelihood is that parts of this
would have been a lot around alot longer than that. As you say
we've got a canopy of oak andash mainly with some birch. And
then underneath we've got ahazel Holly and in places maple
(03:52):
understory. And previously inthe woodland, some areas were
coppiced, and we reintroduced abit of that coppice a few years
ago. And so we're just doingvery small sections though.
Obviously, the woodland is isvery precious for not just the
back Stein's, but all sorts ofother species, including door
(04:12):
mice. We get a quite a niceorchid called bird's nest
orchids, which is a parasite orsaprophyte. And yeah, and we've
got in brackets total. There's2799 species recorded since
we've taken on the reserves.
Steve Roe (04:33):
And what's your role at Dorset Wildlife Trust about
Steve Masters (04:35):
the Wildlife Trust? I'm the ecologist. So I
go across all the reserves inthe ecological survey work,
anything from floral surveys toinverts to bats. And then with
the bat group, I was on thecommittee for Dorset bat group
up until about a year ago. Andthen yeah, then a lot of work
with Dorset back group over thelast sort of 20 years I suppose.
Steve Roe (04:58):
And how does this compare to Have some of the
other reserves obviously you'rein Dorset you've got things like
the Ladybird spider and allthose other sort of iconic
British species. How does thiscompare with some of those other
sites?
Steve Masters (05:08):
Well, as far as Dorset wildlife trusts go, this
is probably my joint favouritereserve, I have to say. And not
only because of the woodland,but also we get Marsh artillery
butterfly in the meadows, whichis quite a rare breeding
butterfly species in the UK andDorset. And, and we also get
those other nice species like weI think we've got about maybe
(05:29):
400 or so species of mosses,liverworts, in lichens, some of
them quite rare. So yeah. Andit's quiet as well. Because
we're in a hidden corner of WestDorset, you very rarely see
anybody here.
Steve Roe (05:42):
It's great for recording. This is like ideal.
There's no cars, there's notraffic, there's no background
noise, just the sound of peopledoing decent conservation work.
Steve Masters (05:50):
It's a great spot. It's a really nice spot if
you want to come for a walk andnot see anyone and just get
immersed in the woodland really.
Steve Roe (06:01):
And there's a bit of woodland coming up. Haven't been
having pasture. No, that's anopen pasture over in the middle.
Why is that area still grey,Steve?
Steve Masters (06:09):
And so yes, we've got a section of woodland.
There's a couple of sectionswoodland, one section that was
conifer, where conifers weretaken off. And then a section
that has been opened up slightlya bit more by taking up some of
the ash, which has been restoredto sort of a wood pasture
landscape. And so which is areally vital landscape for a
(06:30):
whole lot of species. Theheterogeneity of that kind of
landscape is brilliant for allsorts of invertebrates, bats,
door mice, you know, all sortsof species really. So yeah, so
we're doing that. So that's whyit's grazed by currently a nice
herd of Highland cattle. Nice.
Yeah. So yeah, they spend prettymuch the whole year out here.
(06:51):
And then the off the kind ofwetter bits in winter. But yeah,
mainly the whole year. Yeah,they do a good job at eating the
kind of roughest.
Steve Roe (07:03):
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. Andyou can see all these blokes
woodland are really wellconnected, how well connected
his brackets coppice to the restof the landscape.
Steve Masters (07:15):
Yeah, so it is really well connected. So from
here you as you stretch out fromthe woodland on various
different hedgerows and littlecompasses, and it connects into
some other big blocks ofwoodlands. So for example, from
here, it connects over to ourreserve at Kinchen meadows,
which is probably about 2k away,but it's all connected up by
hedgerows. And from there, itconnects into Powerstop common,
(07:38):
where we know there are othermaternity colonies of
Bechstein's bats. And then itconnects up the other way over
the border into Somerset. Yeah,so it's really, really well
connected and obviously gotchattington woods as well, which
is nervous. So yeah, so it's theperfect kind of connected
landscape for bats to be able tomove around.
Steve Roe (07:58):
And is there any part of the reserve open to the
public or was all completelyprivate for you guys?
Steve Masters (08:02):
No, it's all open to the public. Yep. So although
you don't you rarely see aperson out here. It is all open
access. Yeah. So most of ourreserves are all open access.
There's just a few where wemight have like farming
operations that we don't allowpeople. So yeah.
Steve Roe (08:19):
So we've just heard from Steve, a bit about the
woodland and its importance. Andhe's mentioned, obviously, we're
checking boxes today, Patrick,you want to introduce yourself?
And then how many boxes are wechecking today? And who's
helping us?
Patrick Wright (08:30):
So yeah, I'm Patrick Wright. And the senior
scientists scientific officer atthe bins and Wildlife Trust. And
so we are wet rag is called thisbecause a really special site,
because we have 85 bat boxesthat we're gonna check. We're
with a group of volunteers, withthe hope to find the maternity
colony effect size bats, thatwe've been ringing for 24 years
(08:51):
now, we've already found twoboxes with some bats. And I
think we were just doing somemore checks. And hopefully we
processing them later thisafternoon. So
Steve Roe (09:04):
just tell us a bit about the type of boxes we've
got, why this why this stylebeen chosen. And you say you've
been bringing them for 24 years,did the box appear almost
immediately? What's the historyof the site? Yeah.
Patrick Wright (09:14):
So it's actually a really interesting history for
this one. So it started back in1998, I think in March 1998,
where the Dorset bat groupthought it would be a good idea
to put up a few boxes in thisreserve. And three months later,
I think they had a wholematernity colony of Bechstein's
bats. And so that's quitespecial. It was a huge discovery
(09:35):
because back then, we only knewof one colony in the UK, and
like just the odd records in thehibernation sites. So this was a
huge discovery with a secondmaternity colony and also like
an amazing opportunity to dosome research to learn more
about this probably the mostelusive bat in the UK back then.
So the following year, dependson wire trust UK on the ringing
(09:57):
scheme. So they've been ringingthe bats Every year since then,
so this was mostly done by ColinMorris back back in the days.
And now my colleague Marina hastaken over. And so we have yeah,
like I said, 85 to 82 fN boxesin The Woodlands. And so these
are sort of made of cement andsawdust, and kind of mimic the
(10:18):
perfect rooster backsides batchwas just a woodpecker hole. And
then we have these bigger, muchchunkier one FW ones, the
hibernation boxes, which arevery similar, but just big
chunky ones where we tend to getthe whole maternity colony with
all the pubs back in when themonth of June and July, that's
where they tend to be.
Steve Roe (10:39):
And how big is that maternity colony? Has it grown
over the years was it stayedfairly consistent?
Patrick Wright (10:44):
So we think that the colony has stayed fairly
consistent over the years. Thatsaid, we have had like our peak
years over the past two yearswith I think we're just last
month was our highest numberwith 121 bats, roughly 70
adults, and so 50 juveniles thatwe ringed and so yeah, we know
(11:06):
how they are. Each single bathere. So we actually had our
oldest baton ever recorded backin in May, and she's 18 years
old. And
Steve Roe (11:16):
you know how old they are? Because you've been able to
bring those juveniles whenthey're large enough to be
ringed? How many then are youbringing each year? And do you
end up? Are you confident thatyou catch and wring every
juvenile? Or do you dosubsequent checks? How often do
you do the checks? And do youend up ringing later in the year
when you find the last fewstragglers?
Patrick Wright (11:34):
Yes. So in total, I think we've received
close to 1000 bats over the past24 years. And we're fairly
confident we get all thejuveniles, but actually once, so
I would say 50% of thepopulation disappears once they
are well past the first fewmonths, because we never see the
(11:55):
males once we ring them. Theytend to live solitary lives. So
we get very few recaptures ofthe males. And we only tend to
recapture the females who justare very consistent visitors of
these, these boxes. So yeah, wetend to ring all the Youngs in
late July when they're when wethink they're sort of big enough
(12:19):
pretty close to adult size. Andif we think some might be a bit
too small, yeah, so we just waitthe following month, see if if
they're there and ring them butyeah, I would say we probably
get 95% of the population maybemaybe close to 100%
Steve Roe (12:34):
and you're waiting to ring them to get to a certain
size so that things like thering don't slip off the wink.
We've listeners will have heardus talk about ringing before but
just has been ringing and thenyou mentioned recaptures there.
Do you ever get recapturesoffside? Do you get records from
local back groups in the area?
Patrick Wright (12:49):
Yeah, so the ringing is essentially just
putting a little ring aroundtheir forearm and so we just
want to make sure backsies batstake rings quite well. We've
rarely very rarely have issueswith other species. You can have
issues, but very rarely haveissues with the back Stein's.
Once we put them on we get torecapture them check their ring
(13:11):
numbers. We have very fewrecaptures outside. So I think
Colin found a few males in awoodland nearby. That's the only
bit of history of recaptures offsite I've heard ya know, and
when we're not 100 Central,where these bats tend to swarm.
So this is when, in October, theback Stein's and particular
(13:33):
Myotis bats also tend to travelfairly long distances to get to
these hibernation and matingsites. 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 swarmingsites so we're not quite sure
where they go for thehibernation as well
Steve Roe (13:53):
as scuffling in the background as Jimmy is
struggling to get onto theladder because the amount of
undergrowth it's a really nicebit of woodland, isn't it? Have
you ever done any work in termsof working out where the bats
foraging the woodland? Do theyforaging this woodland or do
they golf site?
Patrick Wright (14:05):
Back in 2001 of the very first radio tracking
studies for the species happenedin this woodland So Colin Morris
and Henry Schofield spent thewhole summer just tracking some
of these bats think about adozen of them. And so backsides
are really sedentary that veryfew of them actually left the
woodland. So I think out of theorder bats are they radio
(14:26):
tracked, they use about 75hectares, which is actually a
really small area. They raidattract a couple of males as
well. They moved by maybe 100metres from the night roost, the
females would met sometimes go abit further away. But uh yeah,
they are very sort of sanitaryforagers these these big stones.
Steve Roe (14:48):
So we've got about 10 volunteers today and the other
team with Marina have split intoand they're going the opposite
way round, so we're sort ofworking towards each other and a
big circle around the woodland.
How long do you reckon this isgoing to take to date? Are we
out for the full day
Patrick Wright (15:00):
If it will be a full day for sure that we
started bit after 1030, then Ireckon 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 shouldbe a fairly quick process today,
although we probably might get100 bats, but we've done most of
the bringing last month. Sothere'll be very little ringing
(15:22):
to do hopefully this month, weleft a few actually, we think we
had four juveniles last monththat we didn't ring because we
thought they might be a bit toosmall. So might bring those ones
but other than that, we'llmostly be processing the bat. So
we'll be reading the ringnumber, measuring the forearm,
wearing them turn about theirreproductive status. So whether
they're lactating postlactating, probably this year,
(15:45):
because the Youngs will be a bitmore independent. And and then
we just put them back in thebox. And, yeah, there'll be done
for the day. And we will also bedone.
Steve Roe (15:55):
You said we might get 100 bats so casually. I mean,
it's a really special site. Whyis it the you'll have bats and
why do you enjoy working withDWT so much?
Patrick Wright (16:04):
I'm very lucky with Viola tears, I'm so I'm a
senior scientific officer, whichmeans I don't work just on bats.
I also work on carnivores. So Ihave the best of both worlds. So
yeah, I definitely like keepmyself busy with lots of
interesting things. And that's,I think, I think what I find
particularly interesting withwith this species as well, so,
(16:26):
Vito to fund in my PhD, whichwas actually on backsies bats,
and I think for such a smallanimal here that they live such
long lives, which is veryunusual already. But their
behaviours tend to be a lot moresimilar to other sort of large
animals like elephants, orkiller whales, for example,
(16:47):
where they have these maternitycolonies, where the females sort
of have a lot of knowledge onwhere they need to roost. And so
they share a lot of information.
And the males tend to live theirboring solitary lives. But
actually what we find and insometimes in September checks,
we have a bunch of juveniles,like 15 juveniles, with two or
(17:08):
three or four oldest females. Sothese bats are about 15 plus
years old. And so studies thatare done on cutaways, in
particular, tend to suggest thatis like these old females tend
to play a huge role in sort ofknowledge sharing, teaching, or
the young ones, where the foodis where the roosting sites are.
(17:30):
And my theory is that the backStein's also have similar
behaviours, where they're justtrying to share as much
information as possible to theyoung ones. So that, no, they
just know how to sort of findall the food and the roosting
sites to survive for you know,another few years. 17 If they
can, or 19 is the record forfemale so you
Steve Roe (17:56):
guys have just finished checking these boxes.
So shall we get into it smallboxes, then we'll talk a bit
about the ecology of Epstein'sshort legged Yeah, and
Patrick Wright (18:07):
we never can never find it.
Steve Roe (18:12):
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'sbat ecology then.
Patrick Wright (18:19):
Yeah, so the best sign is bat is what we very
much call a woodland specialist.
And that's because so thematernity colonies in particular
are specialised into roostingand woodpecker holes. And so not
only are they recent woodpeckerholes, but they need a lot of
them. So about, maybe they canuse up to 50 different routes
(18:41):
within a single year. And theyalso don't like to forge very
far. So they need essentially aplace with lots of woodpecker
holes, and lots of food nearby.
And so, this definitely fits ofthe woodland sort of habitat,
especially ancient woodlands,where you have lots of different
(19:04):
insects to eat. So actually,backsides are not super
specialists. When it comes totheir diet, they'll eat pretty
much anything they can find. Butthey need a lot of fit nearby.
So very much a woodenspecialists that will never
forge very far from sort oftheir roosting sites. And the
males, obviously are not asfussy because they don't need to
(19:28):
lactate they don't need to feedtheir young. So they can use
sort of what we call sub optimalwoodland habitat. And we can
find them roosting in sort oflots of odd little crevices and
they're not so dependent on thewoodpecker features. We haven't
been these ones before might getthe odd ones I don't even the
(19:51):
ones over there. We've got hadlike the odd like to the bats,
even after leaving. Oh, maybeyeah, possibly. Yeah.
Steve Roe (20:01):
So Patrick, you said they like, naturally woodpecker
holes, why then obviouslythere's loads woodpeckers in
this woodland. Why are theyfavouring these boxes? And how
are you confident that they'renot elsewhere? In those more
natural risk features, then?
Patrick Wright (20:13):
That's good question. Actually, so Colin,
who did ringing, he always saidthat he very rarely sees
woodpecker holes in thiswoodland. So although like, it
looks like a perfect woodland,where it might be fulfilled,
like a house, maybe one of thereasons why the bats moved in
right away into these bat boxeswas because they actually we're
(20:37):
missing a few sort of keyfeatures. And obviously, we only
do one check per month. So wedon't have the full picture,
maybe they are using other otheractual real woodpecker holes.
But the fact that we're we'rejust we can predict really well,
their behaviour. So we, prettymuch every month we get the bats
(21:02):
and we know that in in May,we'll get the bats in different
groups. And then June, July, thematernity colony will pretty
much always guarantee that we'llget them in the big one FW
boxes. And again, in the, in theAugust September checks, pretty
(21:22):
much always guaranteed thatwe're gonna get maybe three
little groups of bats in thewoodland. So we can't be 100%
Sure, but just my experience, Ithink we can sort of get an idea
that they seem to really likethese boxes. And maybe it could
just be a fact that there's,they just love these boxes here.
(21:42):
Or, and there's they're lackingsome key features in this
woodland for the bats to usethem, as well. So maybe it wants
this, maybe that if there's moresort of features, and the trees
further down the line mightactually stop seeing them. You
know.
Steve Roe (22:02):
And you said earlier, they're quite rare about the
special bath, because obviouslya lot of gaps in the knowledge.
And that's one of the thingsthat your PhD was doing was
trying to fill one of those gapson it tells a bit about the PhD
where you did. Yeah. So
Patrick Wright (22:14):
during my PhD, I was a lot focused on population
genetics, and understanding howsort of populations in the UK
are connected, and how thelandscape affects this. So we
sampled a lot of colonies in theUK, and looked at the levels of
inbreeding. Because you'd think,as a woodland bat, very, very
(22:38):
specialised into living within awoodland habitat fragmentation
might impact sort of how thesecolonies are related. And maybe
you'd have higher levels ofinbreeding, as I mentioned
before, they also swarm which isreally linked to the species
ability to disperse when itcomes to mating. So actually,
(22:59):
what we found is that thealthough they're very sedentary
and stick to their sort of localpatch of woodland, when it comes
to sort of foraging and summonbreeding, when it comes to the
mating season, they're verywilling to go very far. And that
sort of really helps for thesurvival of the species, and
linking different populationsactually, in some are not linked
(23:21):
at all. So actually, that's whatwe found is that there's very
little sort of populationstructure within the backsliders
population. So all of thesepopulations seem to be fairly
well connected, except for onepopulation, actually, which it
stands out on when you look atthe range of backsides bats,
it's in Buckinghamshire, so it'sthis burn wood population where
(23:42):
there's only one very, veryisolated as the only population
where we found actually quitehigh levels of inbreeding. So
this could be that they're notjust the distance to travel to
reach other swarming sites mightbe too far. So they're not
connecting with these other themain population that might be
impacting that. So I think,yeah, that they're willing to
(24:05):
sort of maybe travel up to 20kilometres through sort of sub
optimal habitat to reach theseswarming sites. But more than
that, I think it startsimpacting 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 thepopulation. You know, if you're
(24:27):
cutting trees down, there'll beless food, less routing features
that will affect the survival ofa colony in a bit different way.
Steve Roe (24:36):
So how did you go about collecting all that data
then? Was it were you usingexisting data? Were you going
travelling at different sitesand then how you're actually
getting the genetic material?
Patrick Wright (24:45):
So we take wing punches for that, so do a little
hole in the wing. So we have todo it under Home Office licence
actually doesn't really harmthem. So we sampled eights eight
colonies, so there are a fewother box games How in the UK.
And then the rest was done withsome trapping. So we put do some
(25:06):
heart traps and acoustic laws,which is like the typical way to
catch backsides bats andwoodlands in the UK. And so that
helped us sort of get a sort ofincrease our data, sample size.
And then so then it was straightinto the lab, extracting the
DNA, and we did PCR, we'relooking at the levels. So
(25:30):
looking at heterozygosity so forexample, heterozygosity and
homozygosity in different siteswithin the genome of the each
individual and from that we cansort of determine sort of the
sort of statistics the levels ofinbreeding, how connected each
population is and so on. You
Steve Roe (25:48):
make it sounds so simple. And when you say a hole
in the wing, it really is a tinylittle hole in the wing, isn't
it? Yeah, so
Patrick Wright (25:54):
it's these biopsy punches that are to three
millimetres depending on whatyou use. And yeah, within a
month the bat orphans tend toheal we've well after a year you
can barely tell that they'vebeen sampled. So yeah, so that
wing sort of tissue is one ofthe fastest healing mammalian
soft tissues from what I'veheard of. And yeah, it does
(26:17):
definitely seems to heal reallyfast.
Steve Roe (26:20):
These guys have done these boxes so crack on that's
not so you can hear on the audiotrack how much noise there is as
we're walking through thevegetation. Patrick just want to
describe how dense theunderstory has and why
understory is and why is it thebacksides love the understory
(26:41):
canopy so much. Yeah,
Patrick Wright (26:43):
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 thatone. Yeah, so quite a lot of the
radio tracking studies that haveshown that Bechstein's love at
one nice woodlands with loveoak, but also nice dense Hazel
(27:05):
understory, or understory ingeneral, but particularly Hazel,
and Holly, they do seem toprefer those type of habitats, I
guess it just gives them thissort of structure on the
woodland with a lot of well,possible food for them, because
they don't want to forge too farfrom their roosting sites. So
they need structure, differenttypes of habitat within the
(27:27):
woodland, they spend a lot oftime high up in the canopy, they
also come down and glean on theground to feed. And actually,
it's very handy in the UKbecause this understory is used
sort of to catch them. So we putup often the heart traps under
nice Hazel tree with a rule andthe bats will sort of come down.
(27:49):
And that's how we'll catch them.
Actually, when we tell this toour colleagues on the continent,
they think it's hilariousbecause they don't actually find
Bechstein's that way, becauseit's impossible to catch. Back
Stein's will hop traps, theyjust put hundreds of metres of
Miss nets in the hope that theywill get the odd back stones.
But so definitely in the UKseems to be a key feature. But
backsides are going to thinkabout it like quite sort of
(28:13):
widespread throughout all ofEurope. And they will use other
sort of types of woodlands. Andwe're what we think is perfect
habitat for Bechstein's otherpeople on the continent. Why
just like, that's not where wefind where we find our
Bechstein's. But yeah, one keything definitely seems to be a
(28:34):
nice, old oak trees that that'sdefinitely where they prefer.
Steve Roe (28:41):
We think we're about to maybe other teams or
whatever. And then we're stillflooded, and hopefully then
we'll go and get some processingthem with with the attendees
colony. So Patrick was handsomeenough on X, we've got a mask
on. We've just had lunch. Andwe're nailing on blanket when
explained what marinas doingwith a boxer the minute Yes,
Patrick Wright (29:02):
so we just took the the box down from the tree.
And we have the box covered now.
And Marina is just about to openthe box. And she's going to very
carefully gently extract or theor the bats that are roosting
inside. And we're going to putthem in that box. And once
that's all done, we'll be ableto start processing the bats.
Steve Roe (29:30):
And what sort of biometric data are you gathering
from them?
Patrick Wright (29:33):
So one of the first things we do is measure
the form. So that gives usinformation on sort of the
growth of individuals over theyears. There's actually been a
paper published on looking athow climate change and like hot
years are impacting the size ofthe individuals. And then we're
going to weigh them and look atsort of their ring number
(29:56):
because we know whichindividuals which and And yeah,
breeding status, and then I'llbe damned on for the day we'll
put them back in the box andhang them back up. Nice
Steve Roe (30:13):
Marina and Patrick and Sam and the rest of the crew
just starting to press the bat.
Jim is on again. You've movedpost? Well, you've started a
temporary post with PwC for thenext few months, she just want
to describe for, for peoplelistening who don't know what
bedtimes look like trying todescribe a bedtime.
Jim Mullholland (30:34):
Well, where do I begin, I guess I'll start with
the face in the years. So we allknow that bats will navigate and
hunt using echolocation to thesigns they produce that sound
gets sent out into theenvironment. And then they
listen to the returning echo.
And we have a few specialistswho can either hunt passively,
(30:55):
or switch off theirecholocation, depending on what
they're doing at the time andBechstein's about so one of
those they have these huge ears,either side of the head and
often mistaken. With brown longeared bats. One of the key
differences is that the earshave a clear separation through
the middle. And they don'tretract in the same way that
(31:17):
brand login bats is do whenthey're at rest. They have a
lovely kind of long dog likemuzzle kind of pinkish face.
Lovely white belly, Brian back.
And I think that's all I got tosay about well, they look like I
(31:39):
think I've run out ofcharacteristics, I
Steve Roe (31:40):
can talk about that.
Quite a long Muslim, they looklike Fox like, yeah,
Jim Mullholland (31:45):
we've got a mixture of adults and juveniles
here. So we've got some that arekind of the typical orangey
brain as you would expect in theadults. But as with a range of
different bat species, thejuvenile of the year look,
typically slightly more grey,than the kind of brainy adults,
I might step back, just so I cantake the mask off as I'm
(32:07):
talking, breath in.
Steve Roe (32:11):
And just describe how these guys have been fitting
rings to these paths. And forpeople haven't seen bat rings
before.
Jim Mullholland (32:18):
Yeah, so the bats are tricky to mark in this
way. And we want to mark them.
So when bats are recaptured inthe future, we have a known
history of the individual thatwe're dealing with. And there's
all sorts of studies that canflow from that. So thinking
about minimum ages orpopulations, that kind of the
distribution within thepopulation itself, you know,
(32:39):
whether it's ageing, whetherit's a young population, how
successful certain bats are atbreeding, and unlike birds,
where the rings are fitted overthe ankles, and they're fairly
standard size, and myunderstanding is that they're
fitted with pliers. So in everysingle ring, that's the same
design gets fitted in prettymuch exactly the same way. We
don't have a free ankle to beable to fit rings on to bats. So
(33:02):
we ended up putting them on thethe forearm. And of course, on
one side of the forearm, we havethe wing membrane itself. And so
we're not able to close the ringfully because if we were to do
that, that would puncture anddamage the wing membrane, which
we want to avoid. And so we havean open ring. And so it slides
on top of the forearm. And thenit gets closed down to a size
(33:27):
that we think is sufficientlysmall that it won't come back
off the forearm. But equally, weneed 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 gettrapped within the ring itself
either. So if you think abouthow bats move, typically
(33:48):
roosting, they will be hungupside down. And so presumably
the rings will be closer to thewrist. And when they're flying
around, they will change in allsorts of different directions.
So there's possibilities for thering to move up and down the
forearm itself. And because thewing retracts, that's when the
(34:08):
the finger bones can potentiallycome into contact with the ring,
which we want to avoid thatentanglement basically. So it's
a little bit of an art involvedin this.
Steve Roe (34:35):
So this data has been collected for many, many years
now, who's using the data andwhat gets done with it. People
Patrick Wright (34:41):
didn't actually know that when they started
ringing back in 99, that thiscould be used for, you know,
some random guys PhD in 2050.
And so you never know what kindof opportunity may arise. So, I
often see used some of this datafor my PhD but then recently
We've been collaborating withresearchers at Exeter
University, and they've beensort of analysing this dataset
(35:05):
and extracting information on,for example, the lifespan of the
bats. So we found that althoughwe get some pretty old bats
around 18 years old, what 18 isour oldest one, but actually
most of them live five years,Max. Yeah, the lifespan is five
to six years survive on thefirst year is very poor. So half
of the bats that havefortunately we bring the first
(35:27):
year, we're not going to, we'renot going to see them, half of
them being male, so we're notgoing to see them again. But
actually, half of them also die.
So we're going to actually goingto see only a quarter of these
baths next year. And thenpotentially, we'll look at the
social networks see looking athow each, all these different
individuals, how they connect,if they have like, preferred
(35:50):
sort of relationships,individuals, or whether they
tend to hang out with most, andso on. So it's a Yeah, the
bigger the dataset gets, like,the more questions we'll end up
with, and yeah, we'll justendless questions. I think this
Steve Roe (36:08):
guy's a process and the third box full of Epstein's.
Patrick, you were talking aboutthe difficulties of monitoring
Epstein's nationwide? Why arethey so difficult to study?
Patrick Wright (36:22):
Blackstone's they tend to sort of roost up
high up in the trees, and theyoften split up in different
groups. And they're performing.
So this fish infusion behaviour.
So, you know, for some of thespecies like the horseshoe bats,
it's really easy, we can just goto a nice barn where the whole
maternity colony is going to bein there easy access, and you
(36:42):
can just do a count of thepopulation. And you can do that
many, many sites as manymaternity colonies that you know
have with back Stein's, first ofall, it's not always easy to
find a maternity colony. Andthen when you catch, for
example, a female, if you wantto find the roost, you actually
have to put a tag on it, trackthem to the roost, whether there
(37:05):
they are. And then if you do acount, it's not very easy to
actually see the bats exiting.
And the count might just be avery small represent
representation of the actualcolony. 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
(37:27):
are trying to do this in manycountries. And everyone's still
struggling for those sort ofissues. And it's not just for
backstage, it's also for thebass like barber sales, and so
on. So yeah, back brackets,compass is kind of like the
ideal situation where you justget all the bats in a box, and
you can sort of get fed ID onthe population and the trends.
(37:47):
But one of the ways we're sortof exploring is to use genetics
as a way to monitor populationsizes. So with the tools that I
mentioned earlier, we can lookat the effective population
size. So this gives us a fairlygood idea of the population size
of the breeding populationsurrounding words of the
(38:11):
location where we are. So ifthis is sort of replicated at
different sites, and alsoregularly, so maybe every five
years, which is roughly thegeneration timer for of the
species, we will be able tohopefully detect the population
trends over a long period oftime. But obviously, this is not
easy to set up because of many,many limitations. But yeah,
(38:35):
ideally, that's what's somethingwe would like to tackle
adventuring, like live trust isjust getting a hold of
population trends for these,these more elusive woodland
species.
Steve Roe (38:47):
So you guys obviously been doing this a long time.
There was a national backStein's Monitoring Survey quite
a few years ago, organised byobesity. Is there anybody else
doing anything?
Patrick Wright (38:58):
Well, there's quite a few black boxes now
black box schemes. So I thinkthey'll someone will show some
more endorse it. So there's ahandful and Herefordshire as
well. Then a lot of radiotracking by back group. So a
lot, there's still a lot ofinterest in, in Blackstone's and
sort of their ecology and sortof just local back groups
(39:19):
wanting to understand more. Butas far as I'm aware, I think
sort of definitely some moreareas of research that are
needed to that we need to lookinto and yeah, I think other
than the sort of the datatracking here and there that
consultants and local backgroups do I think there's a
(39:39):
yeah, that's pretty much it forvaccines.
Steve Roe (39:43):
So it's getting told me it's gone five o'clock now.
We're all really hot andexhausted. Why do you keep going
back month after month? Why doyou love it so much?
Patrick Wright (39:51):
I guess it's just the adrenaline and you
never know what you're gonnaget. But, ya know, it's just
like, just fascinating to I justsee all these bats and you
always like starting to know thering numbers. I think people
like just getting used to havinghearing j two one all day long.
So the j two one or the batsthat have been raised over the
(40:12):
past two years. And so if wehave another bat that starts
ringing about us with a U or Hpeople get quite excited. And
oh, what year was that? Sothat's always quite exciting. So
far, oldest bat is 14 years old.
And what so we've done threeboxes, and that's 70 plus 90
bats. And still probably 2030more to go. And there'll be
(40:35):
Yeah, for we will be done bysix, six ish, I think it's just
Yes, just always so exciting.
Steve Roe (40:48):
A huge thanks to the team at the Vincent Wildlife
Trust and Dorset Wildlife Trustfor having me along for the day.
We've put a link in the shownotes to the bat pages of the
vents and Wildlife Trust. I hopeyou've enjoyed this first
instalment of series five,please tell the world about Bat
Chat on your social mediachannels. And we'll be back in
two weeks time at a roost wherebats emerge from the mouths of
gargoyles see them
Welcome back to BatChat, the award winning
podcast from the BatConservation Trust for anyone
with a fascination in theseamazing nocturnal creatures. I'm
Steve Roe, and this is BatChatseries five.
Yes, hello, we are back with abrand new series and episodes
(00:25):
will be released every otherWednesday from now until spring
next year. If you're new toBatChat, welcome along. I'm
Steve Roe. I'm an ecologist andin 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 andenvironmental management, who
named us as the winner of theNGO Impact Award 2023 for making
(00:47):
a significant difference to theconservation of the natural
environment, as well as spendingthis year recording
conversations for this newseries. We're also really
grateful for those of you whocompleted our listener survey at
the end of the last series.
We've spent the summer goingthrough those suggestions, and
we'll be implementing as many aswe can over the coming series.
(01:09):
One of those suggestions was tohave more species specific
episodes and so here we are anepisode all about the
Bechstein's bats. This episodecomes to you from a Dorset
woodland. It's a place I visitedseveral times for over a decade
and the approach involvesdriving through a narrow dorsal
lanes with lovely tall hedgerowsVISTAs appearing where you can
follow the hedges across thelandscape, forming the
(01:30):
boundaries of small fieldparcels. Meeting staff of the
Vinson Wildlife Trust and DorsetWildlife Trust at the entrance
to the woods. This conversationstarts as the team begins to
check the bat boxes spreadthroughout this reserve.
So it's the middle of August andI'm in one of my favourite
places in the world to come andsee bats on down in the depths
(01:51):
of Dorset and Steve Masters fromDorset Wildlife Trust is going
to tell us where we are and abit about what we're doing today
in the woodland and why the WestWoodland is so special.
Steve Masters (02:02):
Yeah, so we are in the darkest depths of West
Dorset brackets coppice so thesite here Dorset Wildlife Trust
data reserves 45 hectares it's amixture of a lot of different
habitats from semi naturalwoodland. It's on the ancient
woodland inventory, which iswhere we're stood now to neutral
meadows, unimproved. We've got ariver that runs through the
(02:26):
middle, as well as also somewood pasture. Trust has been
involved here since about 1964.
So that's the Wildlife Trust.
And we took on the main block ofthe woods in 1987. And then
since then, we've acquired otherparts of the wood with the last
bit been acquired at 2002. Andtoday we're out checking the bat
(02:47):
boxes, which were put up in1998. I think the first ones by
Dorset bat group, and a ladythat was very involved with that
was a lady called Maureen Keats.
And she was also very involvedin brackets caucus and she loved
reserved and since then VWTVincent Wildlife Trust have put
up more bat boxes. And we're outchecking for the maternity
(03:09):
colony of Epstein's
Steve Roe (03:13):
and the woodland is saying some woodlands like we're
looking, we're stood in just offthe footpath and it's quite
difficult to see very farthrough the woodlands. So if I
can see the next day long afterthat it's quite a enclosed
understory, isn't it? How old dowe think the woodlands is Have
we got any idea at all?
Steve Masters (03:30):
Well, if it's on to Part of it's on the ancient
woodland inventory, which Ithink means it's at least been
around since 1600. But thelikelihood is that parts of this
would have been a lot around alot longer than that. As you say
we've got a canopy of oak andash mainly with some birch. And
then underneath we've got ahazel Holly and in places maple
(03:52):
understory. And previously inthe woodland, some areas were
coppiced, and we reintroduced abit of that coppice a few years
ago. And so we're just doingvery small sections though.
Obviously, the woodland is isvery precious for not just the
back Stein's, but all sorts ofother species, including door
(04:12):
mice. We get a quite a niceorchid called bird's nest
orchids, which is a parasite orsaprophyte. And yeah, and we've
got in brackets total. There's2799 species recorded since
we've taken on the reserves.
Steve Roe (04:33):
And what's your role at Dorset Wildlife Trust about
Steve Masters (04:35):
the Wildlife Trust? I'm the ecologist. So I
go across all the reserves inthe ecological survey work,
anything from floral surveys toinverts to bats. And then with
the bat group, I was on thecommittee for Dorset bat group
up until about a year ago. Andthen yeah, then a lot of work
with Dorset back group over thelast sort of 20 years I suppose.
Steve Roe (04:58):
And how does this compare to Have some of the
other reserves obviously you'rein Dorset you've got things like
the Ladybird spider and allthose other sort of iconic
British species. How does thiscompare with some of those other
sites?
Steve Masters (05:08):
Well, as far as Dorset wildlife trusts go, this
is probably my joint favouritereserve, I have to say. And not
only because of the woodland,but also we get Marsh artillery
butterfly in the meadows, whichis quite a rare breeding
butterfly species in the UK andDorset. And, and we also get
those other nice species like weI think we've got about maybe
(05:29):
400 or so species of mosses,liverworts, in lichens, some of
them quite rare. So yeah. Andit's quiet as well. Because
we're in a hidden corner of WestDorset, you very rarely see
anybody here.
Steve Roe (05:42):
It's great for recording. This is like ideal.
There's no cars, there's notraffic, there's no background
noise, just the sound of peopledoing decent conservation work.
Steve Masters (05:50):
It's a great spot. It's a really nice spot if
you want to come for a walk andnot see anyone and just get
immersed in the woodland really.
Steve Roe (06:01):
And there's a bit of woodland coming up. Haven't been
having pasture. No, that's anopen pasture over in the middle.
Why is that area still grey,Steve?
Steve Masters (06:09):
And so yes, we've got a section of woodland.
There's a couple of sectionswoodland, one section that was
conifer, where conifers weretaken off. And then a section
that has been opened up slightlya bit more by taking up some of
the ash, which has been restoredto sort of a wood pasture
landscape. And so which is areally vital landscape for a
(06:30):
whole lot of species. Theheterogeneity of that kind of
landscape is brilliant for allsorts of invertebrates, bats,
door mice, you know, all sortsof species really. So yeah, so
we're doing that. So that's whyit's grazed by currently a nice
herd of Highland cattle. Nice.
Yeah. So yeah, they spend prettymuch the whole year out here.
(06:51):
And then the off the kind ofwetter bits in winter. But yeah,
mainly the whole year. Yeah,they do a good job at eating the
kind of roughest.
Steve Roe (07:03):
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. Andyou can see all these blokes
woodland are really wellconnected, how well connected
his brackets coppice to the restof the landscape.
Steve Masters (07:15):
Yeah, so it is really well connected. So from
here you as you stretch out fromthe woodland on various
different hedgerows and littlecompasses, and it connects into
some other big blocks ofwoodlands. So for example, from
here, it connects over to ourreserve at Kinchen meadows,
which is probably about 2k away,but it's all connected up by
hedgerows. And from there, itconnects into Powerstop common,
(07:38):
where we know there are othermaternity colonies of
Bechstein's bats. And then itconnects up the other way over
the border into Somerset. Yeah,so it's really, really well
connected and obviously gotchattington woods as well, which
is nervous. So yeah, so it's theperfect kind of connected
landscape for bats to be able tomove around.
Steve Roe (07:58):
And is there any part of the reserve open to the
public or was all completelyprivate for you guys?
Steve Masters (08:02):
No, it's all open to the public. Yep. So although
you don't you rarely see aperson out here. It is all open
access. Yeah. So most of ourreserves are all open access.
There's just a few where wemight have like farming
operations that we don't allowpeople. So yeah.
Steve Roe (08:19):
So we've just heard from Steve, a bit about the
woodland and its importance. Andhe's mentioned, obviously, we're
checking boxes today, Patrick,you want to introduce yourself?
And then how many boxes are wechecking today? And who's
helping us?
Patrick Wright (08:30):
So yeah, I'm Patrick Wright. And the senior
scientists scientific officer atthe bins and Wildlife Trust. And
so we are wet rag is called thisbecause a really special site,
because we have 85 bat boxesthat we're gonna check. We're
with a group of volunteers, withthe hope to find the maternity
colony effect size bats, thatwe've been ringing for 24 years
(08:51):
now, we've already found twoboxes with some bats. And I
think we were just doing somemore checks. And hopefully we
processing them later thisafternoon. So
Steve Roe (09:04):
just tell us a bit about the type of boxes we've
got, why this why this stylebeen chosen. And you say you've
been bringing them for 24 years,did the box appear almost
immediately? What's the historyof the site? Yeah.
Patrick Wright (09:14):
So it's actually a really interesting history for
this one. So it started back in1998, I think in March 1998,
where the Dorset bat groupthought it would be a good idea
to put up a few boxes in thisreserve. And three months later,
I think they had a wholematernity colony of Bechstein's
bats. And so that's quitespecial. It was a huge discovery
(09:35):
because back then, we only knewof one colony in the UK, and
like just the odd records in thehibernation sites. So this was a
huge discovery with a secondmaternity colony and also like
an amazing opportunity to dosome research to learn more
about this probably the mostelusive bat in the UK back then.
So the following year, dependson wire trust UK on the ringing
(09:57):
scheme. So they've been ringingthe bats Every year since then,
so this was mostly done by ColinMorris back back in the days.
And now my colleague Marina hastaken over. And so we have yeah,
like I said, 85 to 82 fN boxesin The Woodlands. And so these
are sort of made of cement andsawdust, and kind of mimic the
(10:18):
perfect rooster backsides batchwas just a woodpecker hole. And
then we have these bigger, muchchunkier one FW ones, the
hibernation boxes, which arevery similar, but just big
chunky ones where we tend to getthe whole maternity colony with
all the pubs back in when themonth of June and July, that's
where they tend to be.
Steve Roe (10:39):
And how big is that maternity colony? Has it grown
over the years was it stayedfairly consistent?
Patrick Wright (10:44):
So we think that the colony has stayed fairly
consistent over the years. Thatsaid, we have had like our peak
years over the past two yearswith I think we're just last
month was our highest numberwith 121 bats, roughly 70
adults, and so 50 juveniles thatwe ringed and so yeah, we know
(11:06):
how they are. Each single bathere. So we actually had our
oldest baton ever recorded backin in May, and she's 18 years
old. And
Steve Roe (11:16):
you know how old they are? Because you've been able to
bring those juveniles whenthey're large enough to be
ringed? How many then are youbringing each year? And do you
end up? Are you confident thatyou catch and wring every
juvenile? Or do you dosubsequent checks? How often do
you do the checks? And do youend up ringing later in the year
when you find the last fewstragglers?
Patrick Wright (11:34):
Yes. So in total, I think we've received
close to 1000 bats over the past24 years. And we're fairly
confident we get all thejuveniles, but actually once, so
I would say 50% of thepopulation disappears once they
are well past the first fewmonths, because we never see the
(11:55):
males once we ring them. Theytend to live solitary lives. So
we get very few recaptures ofthe males. And we only tend to
recapture the females who justare very consistent visitors of
these, these boxes. So yeah, wetend to ring all the Youngs in
late July when they're when wethink they're sort of big enough
(12:19):
pretty close to adult size. Andif we think some might be a bit
too small, yeah, so we just waitthe following month, see if if
they're there and ring them butyeah, I would say we probably
get 95% of the population maybemaybe close to 100%
Steve Roe (12:34):
and you're waiting to ring them to get to a certain
size so that things like thering don't slip off the wink.
We've listeners will have heardus talk about ringing before but
just has been ringing and thenyou mentioned recaptures there.
Do you ever get recapturesoffside? Do you get records from
local back groups in the area?
Patrick Wright (12:49):
Yeah, so the ringing is essentially just
putting a little ring aroundtheir forearm and so we just
want to make sure backsies batstake rings quite well. We've
rarely very rarely have issueswith other species. You can have
issues, but very rarely haveissues with the back Stein's.
Once we put them on we get torecapture them check their ring
(13:11):
numbers. We have very fewrecaptures outside. So I think
Colin found a few males in awoodland nearby. That's the only
bit of history of recaptures offsite I've heard ya know, and
when we're not 100 Central,where these bats tend to swarm.
So this is when, in October, theback Stein's and particular
(13:33):
Myotis bats also tend to travelfairly long distances to get to
these hibernation and matingsites. 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 swarmingsites so we're not quite sure
where they go for thehibernation as well
Steve Roe (13:53):
as scuffling in the background as Jimmy is
struggling to get onto theladder because the amount of
undergrowth it's a really nicebit of woodland, isn't it? Have
you ever done any work in termsof working out where the bats
foraging the woodland? Do theyforaging this woodland or do
they golf site?
Patrick Wright (14:05):
Back in 2001 of the very first radio tracking
studies for the species happenedin this woodland So Colin Morris
and Henry Schofield spent thewhole summer just tracking some
of these bats think about adozen of them. And so backsides
are really sedentary that veryfew of them actually left the
woodland. So I think out of theorder bats are they radio
(14:26):
tracked, they use about 75hectares, which is actually a
really small area. They raidattract a couple of males as
well. They moved by maybe 100metres from the night roost, the
females would met sometimes go abit further away. But uh yeah,
they are very sort of sanitaryforagers these these big stones.
Steve Roe (14:48):
So we've got about 10 volunteers today and the other
team with Marina have split intoand they're going the opposite
way round, so we're sort ofworking towards each other and a
big circle around the woodland.
How long do you reckon this isgoing to take to date? Are we
out for the full day
Patrick Wright (15:00):
If it will be a full day for sure that we
started bit after 1030, then Ireckon 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 shouldbe a fairly quick process today,
although we probably might get100 bats, but we've done most of
the bringing last month. Sothere'll be very little ringing
(15:22):
to do hopefully this month, weleft a few actually, we think we
had four juveniles last monththat we didn't ring because we
thought they might be a bit toosmall. So might bring those ones
but other than that, we'llmostly be processing the bat. So
we'll be reading the ringnumber, measuring the forearm,
wearing them turn about theirreproductive status. So whether
they're lactating postlactating, probably this year,
(15:45):
because the Youngs will be a bitmore independent. And and then
we just put them back in thebox. And, yeah, there'll be done
for the day. And we will also bedone.
Steve Roe (15:55):
You said we might get 100 bats so casually. I mean,
it's a really special site. Whyis it the you'll have bats and
why do you enjoy working withDWT so much?
Patrick Wright (16:04):
I'm very lucky with Viola tears, I'm so I'm a
senior scientific officer, whichmeans I don't work just on bats.
I also work on carnivores. So Ihave the best of both worlds. So
yeah, I definitely like keepmyself busy with lots of
interesting things. And that's,I think, I think what I find
particularly interesting withwith this species as well, so,
(16:26):
Vito to fund in my PhD, whichwas actually on backsies bats,
and I think for such a smallanimal here that they live such
long lives, which is veryunusual already. But their
behaviours tend to be a lot moresimilar to other sort of large
animals like elephants, orkiller whales, for example,
(16:47):
where they have these maternitycolonies, where the females sort
of have a lot of knowledge onwhere they need to roost. And so
they share a lot of information.
And the males tend to live theirboring solitary lives. But
actually what we find and insometimes in September checks,
we have a bunch of juveniles,like 15 juveniles, with two or
(17:08):
three or four oldest females. Sothese bats are about 15 plus
years old. And so studies thatare done on cutaways, in
particular, tend to suggest thatis like these old females tend
to play a huge role in sort ofknowledge sharing, teaching, or
the young ones, where the foodis where the roosting sites are.
(17:30):
And my theory is that the backStein's also have similar
behaviours, where they're justtrying to share as much
information as possible to theyoung ones. So that, no, they
just know how to sort of findall the food and the roosting
sites to survive for you know,another few years. 17 If they
can, or 19 is the record forfemale so you
Steve Roe (17:56):
guys have just finished checking these boxes.
So shall we get into it smallboxes, then we'll talk a bit
about the ecology of Epstein'sshort legged Yeah, and
Patrick Wright (18:07):
we never can never find it.
Steve Roe (18:12):
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'sbat ecology then.
Patrick Wright (18:19):
Yeah, so the best sign is bat is what we very
much call a woodland specialist.
And that's because so thematernity colonies in particular
are specialised into roostingand woodpecker holes. And so not
only are they recent woodpeckerholes, but they need a lot of
them. So about, maybe they canuse up to 50 different routes
(18:41):
within a single year. And theyalso don't like to forge very
far. So they need essentially aplace with lots of woodpecker
holes, and lots of food nearby.
And so, this definitely fits ofthe woodland sort of habitat,
especially ancient woodlands,where you have lots of different
(19:04):
insects to eat. So actually,backsides are not super
specialists. When it comes totheir diet, they'll eat pretty
much anything they can find. Butthey need a lot of fit nearby.
So very much a woodenspecialists that will never
forge very far from sort oftheir roosting sites. And the
males, obviously are not asfussy because they don't need to
(19:28):
lactate they don't need to feedtheir young. So they can use
sort of what we call sub optimalwoodland habitat. And we can
find them roosting in sort oflots of odd little crevices and
they're not so dependent on thewoodpecker features. We haven't
been these ones before might getthe odd ones I don't even the
(19:51):
ones over there. We've got hadlike the odd like to the bats,
even after leaving. Oh, maybeyeah, possibly. Yeah.
Steve Roe (20:01):
So Patrick, you said they like, naturally woodpecker
holes, why then obviouslythere's loads woodpeckers in
this woodland. Why are theyfavouring these boxes? And how
are you confident that they'renot elsewhere? In those more
natural risk features, then?
Patrick Wright (20:13):
That's good question. Actually, so Colin,
who did ringing, he always saidthat he very rarely sees
woodpecker holes in thiswoodland. So although like, it
looks like a perfect woodland,where it might be fulfilled,
like a house, maybe one of thereasons why the bats moved in
right away into these bat boxeswas because they actually we're
(20:37):
missing a few sort of keyfeatures. And obviously, we only
do one check per month. So wedon't have the full picture,
maybe they are using other otheractual real woodpecker holes.
But the fact that we're we'rejust we can predict really well,
their behaviour. So we, prettymuch every month we get the bats
(21:02):
and we know that in in May,we'll get the bats in different
groups. And then June, July, thematernity colony will pretty
much always guarantee that we'llget them in the big one FW
boxes. And again, in the, in theAugust September checks, pretty
(21:22):
much always guaranteed thatwe're gonna get maybe three
little groups of bats in thewoodland. So we can't be 100%
Sure, but just my experience, Ithink we can sort of get an idea
that they seem to really likethese boxes. And maybe it could
just be a fact that there's,they just love these boxes here.
(21:42):
Or, and there's they're lackingsome key features in this
woodland for the bats to usethem, as well. So maybe it wants
this, maybe that if there's moresort of features, and the trees
further down the line mightactually stop seeing them. You
know.
Steve Roe (22:02):
And you said earlier, they're quite rare about the
special bath, because obviouslya lot of gaps in the knowledge.
And that's one of the thingsthat your PhD was doing was
trying to fill one of those gapson it tells a bit about the PhD
where you did. Yeah. So
Patrick Wright (22:14):
during my PhD, I was a lot focused on population
genetics, and understanding howsort of populations in the UK
are connected, and how thelandscape affects this. So we
sampled a lot of colonies in theUK, and looked at the levels of
inbreeding. Because you'd think,as a woodland bat, very, very
(22:38):
specialised into living within awoodland habitat fragmentation
might impact sort of how thesecolonies are related. And maybe
you'd have higher levels ofinbreeding, as I mentioned
before, they also swarm which isreally linked to the species
ability to disperse when itcomes to mating. So actually,
(22:59):
what we found is that thealthough they're very sedentary
and stick to their sort of localpatch of woodland, when it comes
to sort of foraging and summonbreeding, when it comes to the
mating season, they're verywilling to go very far. And that
sort of really helps for thesurvival of the species, and
linking different populationsactually, in some are not linked
(23:21):
at all. So actually, that's whatwe found is that there's very
little sort of populationstructure within the backsliders
population. So all of thesepopulations seem to be fairly
well connected, except for onepopulation, actually, which it
stands out on when you look atthe range of backsides bats,
it's in Buckinghamshire, so it'sthis burn wood population where
(23:42):
there's only one very, veryisolated as the only population
where we found actually quitehigh levels of inbreeding. So
this could be that they're notjust the distance to travel to
reach other swarming sites mightbe too far. So they're not
connecting with these other themain population that might be
impacting that. So I think,yeah, that they're willing to
(24:05):
sort of maybe travel up to 20kilometres through sort of sub
optimal habitat to reach theseswarming sites. But more than
that, I think it startsimpacting 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 thepopulation. You know, if you're
(24:27):
cutting trees down, there'll beless food, less routing features
that will affect the survival ofa colony in a bit different way.
Steve Roe (24:36):
So how did you go about collecting all that data
then? Was it were you usingexisting data? Were you going
travelling at different sitesand then how you're actually
getting the genetic material?
Patrick Wright (24:45):
So we take wing punches for that, so do a little
hole in the wing. So we have todo it under Home Office licence
actually doesn't really harmthem. So we sampled eights eight
colonies, so there are a fewother box games How in the UK.
And then the rest was done withsome trapping. So we put do some
(25:06):
heart traps and acoustic laws,which is like the typical way to
catch backsides bats andwoodlands in the UK. And so that
helped us sort of get a sort ofincrease our data, sample size.
And then so then it was straightinto the lab, extracting the
DNA, and we did PCR, we'relooking at the levels. So
(25:30):
looking at heterozygosity so forexample, heterozygosity and
homozygosity in different siteswithin the genome of the each
individual and from that we cansort of determine sort of the
sort of statistics the levels ofinbreeding, how connected each
population is and so on. You
Steve Roe (25:48):
make it sounds so simple. And when you say a hole
in the wing, it really is a tinylittle hole in the wing, isn't
it? Yeah, so
Patrick Wright (25:54):
it's these biopsy punches that are to three
millimetres depending on whatyou use. And yeah, within a
month the bat orphans tend toheal we've well after a year you
can barely tell that they'vebeen sampled. So yeah, so that
wing sort of tissue is one ofthe fastest healing mammalian
soft tissues from what I'veheard of. And yeah, it does
(26:17):
definitely seems to heal reallyfast.
Steve Roe (26:20):
These guys have done these boxes so crack on that's
not so you can hear on the audiotrack how much noise there is as
we're walking through thevegetation. Patrick just want to
describe how dense theunderstory has and why
understory is and why is it thebacksides love the understory
(26:41):
canopy so much. Yeah,
Patrick Wright (26:43):
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 thatone. Yeah, so quite a lot of the
radio tracking studies that haveshown that Bechstein's love at
one nice woodlands with loveoak, but also nice dense Hazel
(27:05):
understory, or understory ingeneral, but particularly Hazel,
and Holly, they do seem toprefer those type of habitats, I
guess it just gives them thissort of structure on the
woodland with a lot of well,possible food for them, because
they don't want to forge too farfrom their roosting sites. So
they need structure, differenttypes of habitat within the
(27:27):
woodland, they spend a lot oftime high up in the canopy, they
also come down and glean on theground to feed. And actually,
it's very handy in the UKbecause this understory is used
sort of to catch them. So we putup often the heart traps under
nice Hazel tree with a rule andthe bats will sort of come down.
(27:49):
And that's how we'll catch them.
Actually, when we tell this toour colleagues on the continent,
they think it's hilariousbecause they don't actually find
Bechstein's that way, becauseit's impossible to catch. Back
Stein's will hop traps, theyjust put hundreds of metres of
Miss nets in the hope that theywill get the odd back stones.
But so definitely in the UKseems to be a key feature. But
backsides are going to thinkabout it like quite sort of
(28:13):
widespread throughout all ofEurope. And they will use other
sort of types of woodlands. Andwe're what we think is perfect
habitat for Bechstein's otherpeople on the continent. Why
just like, that's not where wefind where we find our
Bechstein's. But yeah, one keything definitely seems to be a
(28:34):
nice, old oak trees that that'sdefinitely where they prefer.
Steve Roe (28:41):
We think we're about to maybe other teams or
whatever. And then we're stillflooded, and hopefully then
we'll go and get some processingthem with with the attendees
colony. So Patrick was handsomeenough on X, we've got a mask
on. We've just had lunch. Andwe're nailing on blanket when
explained what marinas doingwith a boxer the minute Yes,
Patrick Wright (29:02):
so we just took the the box down from the tree.
And we have the box covered now.
And Marina is just about to openthe box. And she's going to very
carefully gently extract or theor the bats that are roosting
inside. And we're going to putthem in that box. And once
that's all done, we'll be ableto start processing the bats.
Steve Roe (29:30):
And what sort of biometric data are you gathering
from them?
Patrick Wright (29:33):
So one of the first things we do is measure
the form. So that gives usinformation on sort of the
growth of individuals over theyears. There's actually been a
paper published on looking athow climate change and like hot
years are impacting the size ofthe individuals. And then we're
going to weigh them and look atsort of their ring number
(29:56):
because we know whichindividuals which and And yeah,
breeding status, and then I'llbe damned on for the day we'll
put them back in the box andhang them back up. Nice
Steve Roe (30:13):
Marina and Patrick and Sam and the rest of the crew
just starting to press the bat.
Jim is on again. You've movedpost? Well, you've started a
temporary post with PwC for thenext few months, she just want
to describe for, for peoplelistening who don't know what
bedtimes look like trying todescribe a bedtime.
Jim Mullholland (30:34):
Well, where do I begin, I guess I'll start with
the face in the years. So we allknow that bats will navigate and
hunt using echolocation to thesigns they produce that sound
gets sent out into theenvironment. And then they
listen to the returning echo.
And we have a few specialistswho can either hunt passively,
(30:55):
or switch off theirecholocation, depending on what
they're doing at the time andBechstein's about so one of
those they have these huge ears,either side of the head and
often mistaken. With brown longeared bats. One of the key
differences is that the earshave a clear separation through
the middle. And they don'tretract in the same way that
(31:17):
brand login bats is do whenthey're at rest. They have a
lovely kind of long dog likemuzzle kind of pinkish face.
Lovely white belly, Brian back.
And I think that's all I got tosay about well, they look like I
(31:39):
think I've run out ofcharacteristics, I
Steve Roe (31:40):
can talk about that.
Quite a long Muslim, they looklike Fox like, yeah,
Jim Mullholland (31:45):
we've got a mixture of adults and juveniles
here. So we've got some that arekind of the typical orangey
brain as you would expect in theadults. But as with a range of
different bat species, thejuvenile of the year look,
typically slightly more grey,than the kind of brainy adults,
I might step back, just so I cantake the mask off as I'm
(32:07):
talking, breath in.
Steve Roe (32:11):
And just describe how these guys have been fitting
rings to these paths. And forpeople haven't seen bat rings
before.
Jim Mullholland (32:18):
Yeah, so the bats are tricky to mark in this
way. And we want to mark them.
So when bats are recaptured inthe future, we have a known
history of the individual thatwe're dealing with. And there's
all sorts of studies that canflow from that. So thinking
about minimum ages orpopulations, that kind of the
distribution within thepopulation itself, you know,
(32:39):
whether it's ageing, whetherit's a young population, how
successful certain bats are atbreeding, and unlike birds,
where the rings are fitted overthe ankles, and they're fairly
standard size, and myunderstanding is that they're
fitted with pliers. So in everysingle ring, that's the same
design gets fitted in prettymuch exactly the same way. We
don't have a free ankle to beable to fit rings on to bats. So
(33:02):
we ended up putting them on thethe forearm. And of course, on
one side of the forearm, we havethe wing membrane itself. And so
we're not able to close the ringfully because if we were to do
that, that would puncture anddamage the wing membrane, which
we want to avoid. And so we havean open ring. And so it slides
on top of the forearm. And thenit gets closed down to a size
(33:27):
that we think is sufficientlysmall that it won't come back
off the forearm. But equally, weneed 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 gettrapped within the ring itself
either. So if you think abouthow bats move, typically
(33:48):
roosting, they will be hungupside down. And so presumably
the rings will be closer to thewrist. And when they're flying
around, they will change in allsorts of different directions.
So there's possibilities for thering to move up and down the
forearm itself. And because thewing retracts, that's when the
(34:08):
the finger bones can potentiallycome into contact with the ring,
which we want to avoid thatentanglement basically. So it's
a little bit of an art involvedin this.
Steve Roe (34:35):
So this data has been collected for many, many years
now, who's using the data andwhat gets done with it. People
Patrick Wright (34:41):
didn't actually know that when they started
ringing back in 99, that thiscould be used for, you know,
some random guys PhD in 2050.
And so you never know what kindof opportunity may arise. So, I
often see used some of this datafor my PhD but then recently
We've been collaborating withresearchers at Exeter
University, and they've beensort of analysing this dataset
(35:05):
and extracting information on,for example, the lifespan of the
bats. So we found that althoughwe get some pretty old bats
around 18 years old, what 18 isour oldest one, but actually
most of them live five years,Max. Yeah, the lifespan is five
to six years survive on thefirst year is very poor. So half
of the bats that havefortunately we bring the first
(35:27):
year, we're not going to, we'renot going to see them, half of
them being male, so we're notgoing to see them again. But
actually, half of them also die.
So we're going to actually goingto see only a quarter of these
baths next year. And thenpotentially, we'll look at the
social networks see looking athow each, all these different
individuals, how they connect,if they have like, preferred
(35:50):
sort of relationships,individuals, or whether they
tend to hang out with most, andso on. So it's a Yeah, the
bigger the dataset gets, like,the more questions we'll end up
with, and yeah, we'll justendless questions. I think this
Steve Roe (36:08):
guy's a process and the third box full of Epstein's.
Patrick, you were talking aboutthe difficulties of monitoring
Epstein's nationwide? Why arethey so difficult to study?
Patrick Wright (36:22):
Blackstone's they tend to sort of roost up
high up in the trees, and theyoften split up in different
groups. And they're performing.
So this fish infusion behaviour.
So, you know, for some of thespecies like the horseshoe bats,
it's really easy, we can just goto a nice barn where the whole
maternity colony is going to bein there easy access, and you
(36:42):
can just do a count of thepopulation. And you can do that
many, many sites as manymaternity colonies that you know
have with back Stein's, first ofall, it's not always easy to
find a maternity colony. Andthen when you catch, for
example, a female, if you wantto find the roost, you actually
have to put a tag on it, trackthem to the roost, whether there
(37:05):
they are. And then if you do acount, it's not very easy to
actually see the bats exiting.
And the count might just be avery small represent
representation of the actualcolony. 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
(37:27):
are trying to do this in manycountries. And everyone's still
struggling for those sort ofissues. And it's not just for
backstage, it's also for thebass like barber sales, and so
on. So yeah, back brackets,compass is kind of like the
ideal situation where you justget all the bats in a box, and
you can sort of get fed ID onthe population and the trends.
(37:47):
But one of the ways we're sortof exploring is to use genetics
as a way to monitor populationsizes. So with the tools that I
mentioned earlier, we can lookat the effective population
size. So this gives us a fairlygood idea of the population size
of the breeding populationsurrounding words of the
(38:11):
location where we are. So ifthis is sort of replicated at
different sites, and alsoregularly, so maybe every five
years, which is roughly thegeneration timer for of the
species, we will be able tohopefully detect the population
trends over a long period oftime. But obviously, this is not
easy to set up because of many,many limitations. But yeah,
(38:35):
ideally, that's what's somethingwe would like to tackle
adventuring, like live trust isjust getting a hold of
population trends for these,these more elusive woodland
species.
Steve Roe (38:47):
So you guys obviously been doing this a long time.
There was a national backStein's Monitoring Survey quite
a few years ago, organised byobesity. Is there anybody else
doing anything?
Patrick Wright (38:58):
Well, there's quite a few black boxes now
black box schemes. So I thinkthey'll someone will show some
more endorse it. So there's ahandful and Herefordshire as
well. Then a lot of radiotracking by back group. So a
lot, there's still a lot ofinterest in, in Blackstone's and
sort of their ecology and sortof just local back groups
(39:19):
wanting to understand more. Butas far as I'm aware, I think
sort of definitely some moreareas of research that are
needed to that we need to lookinto and yeah, I think other
than the sort of the datatracking here and there that
consultants and local backgroups do I think there's a
(39:39):
yeah, that's pretty much it forvaccines.
Steve Roe (39:43):
So it's getting told me it's gone five o'clock now.
We're all really hot andexhausted. Why do you keep going
back month after month? Why doyou love it so much?
Patrick Wright (39:51):
I guess it's just the adrenaline and you
never know what you're gonnaget. But, ya know, it's just
like, just fascinating to I justsee all these bats and you
always like starting to know thering numbers. I think people
like just getting used to havinghearing j two one all day long.
So the j two one or the batsthat have been raised over the
(40:12):
past two years. And so if wehave another bat that starts
ringing about us with a U or Hpeople get quite excited. And
oh, what year was that? Sothat's always quite exciting. So
far, oldest bat is 14 years old.
And what so we've done threeboxes, and that's 70 plus 90
bats. And still probably 2030more to go. And there'll be
(40:35):
Yeah, for we will be done bysix, six ish, I think it's just
Yes, just always so exciting.
Steve Roe (40:48):
A huge thanks to the team at the Vincent Wildlife
Trust and Dorset Wildlife Trustfor having me along for the day.
We've put a link in the shownotes to the bat pages of the
vents and Wildlife Trust. I hopeyou've enjoyed this first
instalment of series five,please tell the world about Bat
Chat on your social mediachannels. And we'll be back in
two weeks time at a roost wherebats emerge from the mouths of
gargoyles see them
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