February 7, 2024 • 29 mins
Send us a Text Message with what batty adventures you’ve been up to this summer!
S5E53 This week we join David King who created the BatBox III and BatBox Duet detectors amongst several others for four decades. David tells Steve of how it all came about and they delve into the history of bat detecting, how the Bat Detective book and CD was created and we get an insight into his views on the future of technology used by ecologists and conservationists alike.
- Find David on twitter and Instagram
- BatBox Ltd for their range of bat detectors
- The Bat Detective book and CD
- Want to find out more about bat detecting? Take a look at our guide.
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Steve Roe (00:07):
Hello, you're listening to BatChat, the
podcast from the BatConservation Trust, where we
take you out into the field todiscover the world of bat
conservation.
Welcome back, folks. And as youknow by now, this is the podcast
for anyone with a fascination inthe amazing nocturnal mammals
(00:28):
that fill our skies at night.
I'm Steve Roe professionally,I'm an ecologist and in my spare
time, as well as doing thispodcast, I'm a trustee for the
Bat Conservation Trust.
Well, as you can hear, I'msurrounded by evening birdsong.
I've just called the distantcall of a turtle dove and the
first part of the evening isgoing to make an appearance at
(00:51):
any moment. I'm on a fleetingvisit to Sussex because in the
morning, I'm off to meet ourguests are about to hear who
lives not too far from here. Sobefore I turn into the night,
I'm having an evening walkaround the Napa State with my
trusty bat box three detector isthe only back detector I
actually own which was boughtfor me by my parents when I was
12. I've had the chance to usemost detector models out there
(01:11):
over the years, but it's thisparticular detector, which is
special to me. It's been therewith me for countless nights in
the dark for nearly a quarter ofa century. And for most species.
That was the first time I heardtheir calls. In the morning,
I'll be chatting with the guywho invented it, and how it
became one of the best sellingbat detectors of all time. It's
(01:32):
just gonna pass the summersolstice in June, and I'm sat in
the garden in West Sussex withthe mentor of probably one of
the best selling bat detectors,David King. David, thank you for
coming on that chat. I guess thefirst question is, where did it
all start? How did you get intobats?
David King (01:49):
I was a musician, originally. And I used to make
transducers for guitars. So Iwas involved with electronics.
And I've been interested inelectronics since I was 11.
Since it started, really, Ithink I started because my ex
(02:10):
wife was a zoologist. She wasinterested in bats. And she
became interested in the mid80s. And there was a handful of
people that used to go aroundlooking at bat roosts and things
and it wasn't like it isnowadays. And she wanted
something that would translatethe ultrasonic calls, she knew
(02:34):
they were ultrasonic calls intoaudio. And a few of her friends
had these converted radios. Andso I thought, well, you know,
went back to first principles.
And I thought, well, I couldprobably make something similar.
And I tried. It was in twoparts. At first, there was the
detector part and the amplifierpart. You had to connect it with
(02:58):
a cable between the two wasquite loud. And some people
thought we might disturb thebats. But she wasn't very
impressed with it. And so I wentback into the workshop and came
up with the first MacBooks threeare, which was actually the best
books to I think, because thefirst one was the prototype,
(03:21):
right? Yeah. And again, shesaid, Well, it doesn't tell you
what kind of best it is. And Ithought, well, that's a bit
advanced. So I was quite down inthe mouth about it. I took it
along to a back group meeting.
(03:41):
And we went outside. This is theCornwall Wildlife Trust site.
And we listened to bats outsideand everybody came over to me
said what's that? What's that?
It's picking up all the batsand, and mine isn't. And that
was the backbox, two at thetime. And they became really
interested in one person wasgoing up to the first one of the
(04:02):
early back groups of Britainmeetings in I think it was York
at the time. And she took herback detector with her. And I
thought, well, you know, she'sthey're not going to be very
impressed up there. But she cameback she said, Oh, I wanted to
have the detector back. But shesaid I left it with Phil
(04:25):
Richardson because he wouldn'tlet it go. He said No, please
can I have it please can Iborrow it? And he was so
impressed with it. You wrote alittle article in back chat. And
after that, check startedpouring through the letterbox
for similar devices. And I Itried to keep the teaching. I
(04:48):
was a music teacher at the time.
Tried to keep that going at thesame time. But it became too
difficult after a while and Ihad to swap Horses.
Steve Roe (05:01):
Yeah, David, just before we started recording,
David just passed me a excerptfrom 'Bat Chat', which was the
newsletter of the, back then,NCC. And we we had known that
was about that long ago. Soyeah, it's quite nice to to know
that it's continuing now, thatcompany became stuck electronics
just talk about how the namecame about them.
David King (05:22):
It was an abbreviation of St. Agnes where
I was living at the time thatwas in Cornwall. So it was the
first four letters really S T, aG, so I couldn't think of a
better name at the time. Socalled it Stagg electronics. And
we we sold hundreds and hundredsof these backbox threes. And I
(05:46):
tried to modify it and improveit each version. But in the
early days, I, I tracked thecircuit boards with tape and
pads and etched them myself.
Yeah. Which obviously is done bycomputers. Now it's so easy. But
the first ones were actuallydone by hand. And I used to have
(06:07):
acid baths and things to makethe boards. And I assembled them
all myself. They there werethere was no as it was a kind of
sideline, I wasn't buying vastquantities. And all the time. My
ex wife was saying, Do you thinkdo you think it's worth
(06:33):
investing in? Because I wastrying to persuade her that we
should buy a lot of componentsand start making them big scale?
Yes. She said No, sir. So I, Idid. I did the opposite. How I
am. And we bought lots ofcomponents and made lots of
(06:57):
them. And I couldn't make themfast enough, really. So I had to
give up the teaching. I kept itgoing. Part time I used to teach
it Tura school. I really enjoyedthat. It's great fun, but it
wasn't so lucrative. So Icarried on and thought about
developing the next kind of batdetector, which I think was
(07:21):
called batty is which was adetector built into headphones.
You could switch switch from acentre frequency of 25 kilohertz
and 45 kilohertz, okay. Yeah, sothere's a little toggle switch
on one ear, and you just flickedfrom 25 to 45 kilohertz. So you
(07:42):
could pick up most bats thatway, or the low frequency bat
Sarah teens, not chills, socialcause of longhaired. And 45 pips
would come up louder than 55pips because there will be
higher frequency. But in thosethat was before Gareth had
(08:04):
defined the difference betweenthe two. But it was interesting
that I could have let him hearfrom Gareth, talking about just
about starting work on the two,the two types of phones or types
of pipistrel. And this was aBristol University, a comparison
(08:26):
of different detectors at thetime.
Steve Roe (08:35):
And this is dated 1919. They weren't split up all
the way back until about 92. Sothis is this is January 1990.
And God says, I certainly thinkthat making a tape about workers
will be a good move. The qualityof your recordings is excellent
Tibetan anything that's been sofar produced in the UK. So is
(08:56):
that where the idea of doing theback detective the tape and then
the CD came from?
David King (09:02):
Yes, yeah, I had one of the original tapes that Phil
produced, Phil Richardsonproduced. And they all sounded
pretty much the same. Inpractice, when I went out with
mine, I could hear differences.
So I thought, Well, why not tryrecording, building a tape of
them. And the first tape Iproduced was like an upgraded
(09:23):
version of the one that wasavailable and more species. I
think, after that, I decided todo a CD. That was quite a lot
later. But that one, I was ableto spend more time collecting
recordings. They were allheterodyne there. It was
(09:45):
possible to you know, get somedifferences between bats quite
easily. So I was focused ongetting the hearing better, you
know, people's ability to listenbetter and rather than nowadays,
it's you trust the technologythat I was liked the idea of
(10:05):
trusting the person. An examplehere is to use it talks. Oh.
Look at that. Yeah, that's bitsof information. But if I said,
Look at the giraffe
Steve Roe (10:25):
out on a scrap piece of acetate with black printing
on it's a circle about the sizeof CD, and inside the various
random shapes, and I can't seeany draughon that I Yeah. So
David King (10:41):
your ears will give you some information that you
have to sort of your brain hasto process. And it can do a lot
more than you think it can. Andthat's kind of an optical
illusion. But as soon as Imentioned, giraffes, some people
say oh, yes, of course. Becauseyou put together the bits in
(11:04):
your brain fills in the gaps.
Steve Roe (11:07):
That's amazing. I was going to ask about just going
back to the battery is Yeah, youthink about it now. And it was a
hands free bat detector, whichis free ecologists. And that
work is great. Yeah. Why? Whydid hands free never catch on?
Because they just don't makethem anymore? Do they? Nobody's
done anything. So
David King (11:24):
I found them an economical it was. I really did
it for the love of it. Andbecause I wanted a bat detector
that where I could carry a torchand not trip over in the dark.
The I had to buy headphones fromSennheiser. And they were pretty
expensive. I still Yeah, theywere they had to be comfortable
(11:47):
because you'd be walking aroundfor hours, these things on, and
they had to be light. So Icouldn't get any old pair. And
they weren't cheap onesavailable. But I chose the
Sennheiser ones for the bestquality. But modifying those
wasn't economical, really. Andso I couldn't sell them at a
price that people would say, oh,that's reasonable. And it's just
(12:10):
a question of scale again.
Steve Roe (12:13):
So you've honed down that box three, which is still
the only detector I actually ownis my first bat stack. So when I
got into that to the age of 12,use lots of others through work
and through the back group. Andit's a fantastic little
detector. When then did thetechnology frequency different
division come out? And when didthe really popular detach with
the Dirac come about them? I
David King (12:34):
was persuaded by Colin Catto from BCT. To make a
frequency division detector, Ithought well, why not
incorporate hips nine as well.
And so put one channel frequencydivision one channel heterodyne.
And it came out quite well. Sothat became the duet. The
(12:55):
backbox three was better atheterodyne because it had a
massive speaker in there. And itwas you could run groups of
people. I've got letters frompeople saying I had two or 300
people in my back walk and onlyone detector. It was about books
three, but they could all hearit you see. So that was very
good for walks and talks andthings. But for closers study
(13:19):
people needed to recordfrequency division so they could
look at the thing and actuallyevidence the fact that they'd
seen a 45 Pip. Because with arecording, because if you've
tuned into about detectingyou've got no way of registering
where you're tuned in. So youcould say well, that's a 45
(13:41):
kilohertz pitch, we can say it'sa 55 It couldn't prove it. But
with frequency division, howevercrude it was, you could say you
could show a sonogram of thedifferent pitches. So that was
the first time people couldprove what they saw. And it
started being adopted by moreprofessional bat interest
(14:04):
people.
Steve Roe (14:07):
And was that overall before you sold stock
electronics? Was that the mostpopular detector that you're
making at the time?
David King (14:15):
Yeah, it was the stagger looked electronics
evolved into backbox. Limited.
Later on, I thought well, Ican't call it stag electronics
if I'm not in St. tagless. Sowhen I moved to Sussex who
became backbox limited, samedetectors we were carried on
selling the black box threes, Ithink must have been 10 or
(14:39):
12,000 of those worldwide andthey used to go to every corner
of the planet really. I wasconstantly surprised by how many
how many people from remoteplaces heard about it and asked
about it but Get the blackboxthree, then was replaced by the
(15:03):
duet or not replaced, I keptthem alongside one another for a
little while then then stop thethree. The duet came out. Then
somebody said, Well, after doinglots of bat walks, somebody
said, Why don't you produce onefor children. So I produced the
(15:23):
micro bat, which was based onthe same technology as the bat
is where you could just switchfrom one centre frequency to
another, which made it easy. Andthen you didn't get people
breaking off the tuning knobs,which they did on bat walks. And
it was more of my own. I didn't,although I was earning a living
(15:46):
doing it. I was more interestedin doing it for the benefit of
the people that were interestedin bats. And most of my own
survey work because I startedsurveying at 990. Really, I was
first licenced in 89. I got someBob Stebbings correspondence
(16:07):
here. This is when he first sawthe bat box three. And
Steve Roe (16:13):
like say, he says, I saw the instruments at
Liverpool. So they really wereflying around the country about
them when they at the moment Ihave all of the bat detectors I
need, including the new minitwo, and stress that will be
getting reviewed by experts.
It's really nice to see all thishistory here, isn't it? So I
David King (16:30):
think I must have sent him one to look at. Because
he did ask to review one. He waskind of the guru at the time. So
I I was quite keen on hisopinion of it. And there we are.
There's a letter from Phil, whotalks about the QM C's Well, QM
(16:51):
C stands for Queen Mary College.
Pi Professor Pi was buildingthem the the famous professor
pi, because before that theywere all huge, great devices
that you had to close downsomewhere. Hold gates and things
like that.
Steve Roe (17:09):
Go Yeah, I was gonna say we've last series, we went
over to the British Library.
They've got an exhibition out atthe moment. And part of it is
Batson. They've got Holgate ondisplay. It's a massive thing.
This is really interesting. Sothis review from Phil is saying
the latest QM C mini Scott's atransparent purse best disc with
all the frequencies printed onthat rotates over small elite
(17:32):
led and this is where hesuggested replacing the black
twist knob with a combined discwhich is the version I've
written this BB three I've gothere has a transit a small
transparent desk with all thefrequencies printed on
ingeniously
David King (17:48):
you can think feel for that.
Steve Roe (17:50):
Yeah, we use those minis in douche bag away quite a
lot for backlogs and they wentdown really well. It was dead
easy to say switch between thered, the red, I have the notch
on the green light to the pitchlight. It was really simple.
microbots on the micro batch.
Really simple design. Yeah.
Yeah, they went down reallywell.
David King (18:08):
I was gonna say, because when you do bat walks,
you have to introduce peoplewho've never heard about before,
to what they sound like and whatthey do. And the kind of
detectors that are around noware more focused on recording
and not producing a sound forpeople to listen to, like,
Steve Roe (18:31):
like you say the technology is moving on that
it's all based on a visual cue.
What, what's your view of that?
And does it matter that we'regoing to lose that field skill
over time?
David King (18:43):
Well, my view is that we, we shouldn't lose that
skill. Because it comes alongwith other things, the cheers of
bats and things like that. So ifyou rely totally on technology,
you're you're as vulnerable asthe battery. Basically, if your
(19:04):
battery went flat, you're not asurveyor anymore. So just
somebody's looking at blackthings coming out of a race. But
you can identify a lot of batsby ear with heterodyne and even
time expansion. But you canidentify bats quite easily with
(19:24):
that, because you hear frequencydivision in one year. And
immediately after that timeexpanded episode. And I could go
around and recognise a lot ofspecies apart from some of the
migratory species and of course,just just with time expansion,
(19:45):
because you do get your ear inand you can hear the difference
between four and a halfkilohertz and five and a half
kilohertz by ear quite easily.
Steve Roe (19:54):
So what's your view of the current batch set to
market them?
David King (19:57):
Well, I hope it gets better. I think the sound
quality has gone down, you know,because people are more
interested in the the visualexperience afterwards and in the
office or whatever. Or evenworse than that. They're
interested in what the computertells you.
Steve Roe (20:16):
That I mean, it's always a contentious question,
what is your view of auto ID,then?
David King (20:21):
Well, it's getting there, it's a little bit better
I use it myself for where I'mteetering between one or another
species. I think, well, I'll runit through this and see what
they think. Yeah. And becausethey're drawing on lots and lots
and lots of increasingly moreexamples now, coming down with
(20:42):
decisions between pecotasororitas and Curtis austrack.
Yes, and those are the things Ithink I'm a bit sceptical about,
you know, I can't believe thatthere is a clear cut. And you
see on the screen, it says, oneminute, it's Lakota authorities.
(21:03):
And the next call is awestruck.
Yes. And you think well, ifthey're able to overlap like
that, it's going to bedifficult. So for running
through a whole 1000 files, isgoing to give you a pretty good
idea of what's the
Steve Roe (21:19):
what's your favourite bat call or bat encounter when
you've been recording bats overthe years if you've got a
favourite memory.
David King (21:28):
There are so many of them. Yeah. The one of my
favourites was, I stopped at apetrol disused petrol station in
corn on the way to Cornwall, andI could see Sarah teens catching
me bugs just in the canopy. Andso I stopped and got the
(21:49):
detector out. They weren'tdeterred at all by that. And
watch them really close catchingthese may bugs, you could see
the Beetle in the mouth as theyflew off because they came out
quite early to catch these. Andthat stuck in my head because it
was quite an experience. It waslike a display, especially for
(22:10):
us, which we just sat there andwatch them doing this. Really
close quarters, I suppose inAfrica, in the Kruger National
Park, we caught some gianthorseshoe bats. We had a look at
them as well. This was early onand I had the backbox three
(22:32):
there. So we were able to hearwhat they sounded like. And they
were echolocating. At somedistance, you couldn't pick them
up with the with the backbox.
Three, but that was a verysensitive detector. Anyway, that
one. Yeah. I used to test it inthe early days, but by dropping
a pin up the path and a garden.
(22:52):
And you could hear it right bythe back door.
Steve Roe (22:56):
I remember on a field trip a man to graduate degree we
went to Borneo for a couple ofweeks and took this detector out
with me. And it was stillshooting to fortify for UK.
pipistrelles and switch thisdetector on and within seconds
could hear a horseshoe. And itwas that was like
David King (23:14):
Oh, which which horse he was, I don't
Steve Roe (23:16):
know I need to go.
I've never looked at the book Ineed to kind of look I can't
remember and didn't know at thetime. But it's quite a few out
there seem to remember. Luckily,
David King (23:25):
in Britain, if you're making a bat tape, it's
easy, because we've only got afew species. But you go
somewhere like Africa and or thetropics recently went to Costa
Rica. And there are so many batsthere. I'd have no idea what
they were listening for them. I
Steve Roe (23:46):
mean, that bat tape and CD did the bat detective,
again, got a copy of that. Andthat's how I learned back calls.
And you did and like you say itwas about the sound and
listening to the rhythm and thetonal quality that's an that was
really useful for me when Briancome into the story.
David King (24:05):
Brian and I used to do talks and early back detector
workshops in the 90s, early 90s.
And I talked about the detectorsand he talked about the biology
etc. And we then we go out anddo listening. So that's how I
got to meet Brian
Steve Roe (24:24):
making bad sectors then and and your background as
a musician has taken you allover the place. Really I guess
you've specialised in handhelddevices technology now means
that we've got static remoterecording detectors that go out
and record 1000s and 1000s ofbackdoors. How do you deal with
the storage of backhauls at themoment?
David King (24:42):
I don't collect them anymore because they're, you
know, I haven't got that manyyears left in my life to look
through them all. I mean, it'slike my record collection. I've
got CDs, music CDs, so many ofthem And I think that, you know,
even if I sat down now andlistened for the rest of my
(25:04):
life, I wouldn't get throughthem. Yeah. So you've got to
prioritise. And so I don't, Idon't I don't collect calls
anymore, except if they'respecial, you know, if it's
something really unusual, we'recurrently
Steve Roe (25:19):
seem to be in an era of night vision, thermal, and AI
is the hot topic of the moment.
technology's changing at suchpace. How do you think that's
going to influence how surveysfor bats are done? And we're
just going to become techniciansas these technologies put up a
barrier and put up a barrierbetween us and the bats? I
guess? Yeah,
David King (25:39):
well, they already, surveyors are dividing into two
types, really, you get the typethat the ecologists that are
interested in the biology inthe, in the, the actual animals,
and you've got the professionalsthat just want to do the job,
you know, just find out how manybats are there and what species
(26:03):
they are and, and what they haveto do. So you can approach it
either way. But I prefer thefirst because you actually
experience more. But you can besat in front of a computer all
day. Otherwise, I've put backdetecting in, in to perspective
now because I do so many otherthings. In France now. And that
(26:29):
detecting is just one of thethings but I'm pleased when
people come and say, Oh, tell meabout the bats and they can talk
about them.
Steve Roe (26:36):
Okay, we haven't even touched on the fact that you've
got house over in France and yougo there all the time. What sort
of stuff you got over in yourgarden there.
David King (26:43):
We've had up to 11 species going through the garage
alone. Great horses greatermouse heated, less a horseshoes,
long pluck Otis orators andaustrack es Jeff Roy's three
three kinds of pips, but theydon't have the soprano where we
(27:05):
are Barbra styles sells quitecommon. Yeah, that's with the
bats. But other creatures. Wewe've had a black stork in the
field next door. Golden Orioles.
Regular hoopoes. That's right.
(27:25):
Turtle there. turtledoves. Owls,all sorts of owls, badgers
foxes. And we've got Ragon downin the river at the bottom of
the garden. So we do get to seea lot of stuff there. And every
time we go, we think wow, lookat that moth. Giant emperor.
And, and we get 1000s of moths.
1000s. But I love it there. It'slike It's like England that it's
(27:53):
in Normandy, but it's it's got alot more wildlife a lot more
insects.
Steve Roe (28:05):
One final question I have, why are bat detectors
always in black cases make themreally hard to see why did no
one ever make something that wasin a different colour? Is it
just what was available at thetime?
David King (28:17):
No. Well, when you sell a detector, you sell it in
the daytime. And, and all thatall the sophisticated equipment
was black in those days.
Steve Roe (28:30):
It's been fascinating talk to you, David became Thank
you very much.
David King (28:33):
You're welcome.
Steve Roe (28:36):
A huge thanks to David for taking the time to
give us that fascinating historyand insights. And David, if
you're listening that bottle ofFrench wine you sent me away
with was delicious. We've put alink in the show notes to the
BakBox detectors website as wellas the detector advice pages on
our own website. So if you'dlike to find out more, check out
the links. We'll be back in twoweeks time with the landowner of
the largest number of bat roofsin the country. Catch them
Hello, you're listening to BatChat, the
podcast from the BatConservation Trust, where we
take you out into the field todiscover the world of bat
conservation.
Welcome back, folks. And as youknow by now, this is the podcast
for anyone with a fascination inthe amazing nocturnal mammals
(00:28):
that fill our skies at night.
I'm Steve Roe professionally,I'm an ecologist and in my spare
time, as well as doing thispodcast, I'm a trustee for the
Bat Conservation Trust.
Well, as you can hear, I'msurrounded by evening birdsong.
I've just called the distantcall of a turtle dove and the
first part of the evening isgoing to make an appearance at
(00:51):
any moment. I'm on a fleetingvisit to Sussex because in the
morning, I'm off to meet ourguests are about to hear who
lives not too far from here. Sobefore I turn into the night,
I'm having an evening walkaround the Napa State with my
trusty bat box three detector isthe only back detector I
actually own which was boughtfor me by my parents when I was
12. I've had the chance to usemost detector models out there
(01:11):
over the years, but it's thisparticular detector, which is
special to me. It's been therewith me for countless nights in
the dark for nearly a quarter ofa century. And for most species.
That was the first time I heardtheir calls. In the morning,
I'll be chatting with the guywho invented it, and how it
became one of the best sellingbat detectors of all time. It's
(01:32):
just gonna pass the summersolstice in June, and I'm sat in
the garden in West Sussex withthe mentor of probably one of
the best selling bat detectors,David King. David, thank you for
coming on that chat. I guess thefirst question is, where did it
all start? How did you get intobats?
David King (01:49):
I was a musician, originally. And I used to make
transducers for guitars. So Iwas involved with electronics.
And I've been interested inelectronics since I was 11.
Since it started, really, Ithink I started because my ex
(02:10):
wife was a zoologist. She wasinterested in bats. And she
became interested in the mid80s. And there was a handful of
people that used to go aroundlooking at bat roosts and things
and it wasn't like it isnowadays. And she wanted
something that would translatethe ultrasonic calls, she knew
(02:34):
they were ultrasonic calls intoaudio. And a few of her friends
had these converted radios. Andso I thought, well, you know,
went back to first principles.
And I thought, well, I couldprobably make something similar.
And I tried. It was in twoparts. At first, there was the
detector part and the amplifierpart. You had to connect it with
(02:58):
a cable between the two wasquite loud. And some people
thought we might disturb thebats. But she wasn't very
impressed with it. And so I wentback into the workshop and came
up with the first MacBooks threeare, which was actually the best
books to I think, because thefirst one was the prototype,
(03:21):
right? Yeah. And again, shesaid, Well, it doesn't tell you
what kind of best it is. And Ithought, well, that's a bit
advanced. So I was quite down inthe mouth about it. I took it
along to a back group meeting.
(03:41):
And we went outside. This is theCornwall Wildlife Trust site.
And we listened to bats outsideand everybody came over to me
said what's that? What's that?
It's picking up all the batsand, and mine isn't. And that
was the backbox, two at thetime. And they became really
interested in one person wasgoing up to the first one of the
(04:02):
early back groups of Britainmeetings in I think it was York
at the time. And she took herback detector with her. And I
thought, well, you know, she'sthey're not going to be very
impressed up there. But she cameback she said, Oh, I wanted to
have the detector back. But shesaid I left it with Phil
(04:25):
Richardson because he wouldn'tlet it go. He said No, please
can I have it please can Iborrow it? And he was so
impressed with it. You wrote alittle article in back chat. And
after that, check startedpouring through the letterbox
for similar devices. And I Itried to keep the teaching. I
(04:48):
was a music teacher at the time.
Tried to keep that going at thesame time. But it became too
difficult after a while and Ihad to swap Horses.
Steve Roe (05:01):
Yeah, David, just before we started recording,
David just passed me a excerptfrom 'Bat Chat', which was the
newsletter of the, back then,NCC. And we we had known that
was about that long ago. Soyeah, it's quite nice to to know
that it's continuing now, thatcompany became stuck electronics
just talk about how the namecame about them.
David King (05:22):
It was an abbreviation of St. Agnes where
I was living at the time thatwas in Cornwall. So it was the
first four letters really S T, aG, so I couldn't think of a
better name at the time. Socalled it Stagg electronics. And
we we sold hundreds and hundredsof these backbox threes. And I
(05:46):
tried to modify it and improveit each version. But in the
early days, I, I tracked thecircuit boards with tape and
pads and etched them myself.
Yeah. Which obviously is done bycomputers. Now it's so easy. But
the first ones were actuallydone by hand. And I used to have
(06:07):
acid baths and things to makethe boards. And I assembled them
all myself. They there werethere was no as it was a kind of
sideline, I wasn't buying vastquantities. And all the time. My
ex wife was saying, Do you thinkdo you think it's worth
(06:33):
investing in? Because I wastrying to persuade her that we
should buy a lot of componentsand start making them big scale?
Yes. She said No, sir. So I, Idid. I did the opposite. How I
am. And we bought lots ofcomponents and made lots of
(06:57):
them. And I couldn't make themfast enough, really. So I had to
give up the teaching. I kept itgoing. Part time I used to teach
it Tura school. I really enjoyedthat. It's great fun, but it
wasn't so lucrative. So Icarried on and thought about
developing the next kind of batdetector, which I think was
(07:21):
called batty is which was adetector built into headphones.
You could switch switch from acentre frequency of 25 kilohertz
and 45 kilohertz, okay. Yeah, sothere's a little toggle switch
on one ear, and you just flickedfrom 25 to 45 kilohertz. So you
(07:42):
could pick up most bats thatway, or the low frequency bat
Sarah teens, not chills, socialcause of longhaired. And 45 pips
would come up louder than 55pips because there will be
higher frequency. But in thosethat was before Gareth had
(08:04):
defined the difference betweenthe two. But it was interesting
that I could have let him hearfrom Gareth, talking about just
about starting work on the two,the two types of phones or types
of pipistrel. And this was aBristol University, a comparison
(08:26):
of different detectors at thetime.
Steve Roe (08:35):
And this is dated 1919. They weren't split up all
the way back until about 92. Sothis is this is January 1990.
And God says, I certainly thinkthat making a tape about workers
will be a good move. The qualityof your recordings is excellent
Tibetan anything that's been sofar produced in the UK. So is
(08:56):
that where the idea of doing theback detective the tape and then
the CD came from?
David King (09:02):
Yes, yeah, I had one of the original tapes that Phil
produced, Phil Richardsonproduced. And they all sounded
pretty much the same. Inpractice, when I went out with
mine, I could hear differences.
So I thought, Well, why not tryrecording, building a tape of
them. And the first tape Iproduced was like an upgraded
(09:23):
version of the one that wasavailable and more species. I
think, after that, I decided todo a CD. That was quite a lot
later. But that one, I was ableto spend more time collecting
recordings. They were allheterodyne there. It was
(09:45):
possible to you know, get somedifferences between bats quite
easily. So I was focused ongetting the hearing better, you
know, people's ability to listenbetter and rather than nowadays,
it's you trust the technologythat I was liked the idea of
(10:05):
trusting the person. An examplehere is to use it talks. Oh.
Look at that. Yeah, that's bitsof information. But if I said,
Look at the giraffe
Steve Roe (10:25):
out on a scrap piece of acetate with black printing
on it's a circle about the sizeof CD, and inside the various
random shapes, and I can't seeany draughon that I Yeah. So
David King (10:41):
your ears will give you some information that you
have to sort of your brain hasto process. And it can do a lot
more than you think it can. Andthat's kind of an optical
illusion. But as soon as Imentioned, giraffes, some people
say oh, yes, of course. Becauseyou put together the bits in
(11:04):
your brain fills in the gaps.
Steve Roe (11:07):
That's amazing. I was going to ask about just going
back to the battery is Yeah, youthink about it now. And it was a
hands free bat detector, whichis free ecologists. And that
work is great. Yeah. Why? Whydid hands free never catch on?
Because they just don't makethem anymore? Do they? Nobody's
done anything. So
David King (11:24):
I found them an economical it was. I really did
it for the love of it. Andbecause I wanted a bat detector
that where I could carry a torchand not trip over in the dark.
The I had to buy headphones fromSennheiser. And they were pretty
expensive. I still Yeah, theywere they had to be comfortable
(11:47):
because you'd be walking aroundfor hours, these things on, and
they had to be light. So Icouldn't get any old pair. And
they weren't cheap onesavailable. But I chose the
Sennheiser ones for the bestquality. But modifying those
wasn't economical, really. Andso I couldn't sell them at a
price that people would say, oh,that's reasonable. And it's just
(12:10):
a question of scale again.
Steve Roe (12:13):
So you've honed down that box three, which is still
the only detector I actually ownis my first bat stack. So when I
got into that to the age of 12,use lots of others through work
and through the back group. Andit's a fantastic little
detector. When then did thetechnology frequency different
division come out? And when didthe really popular detach with
the Dirac come about them? I
David King (12:34):
was persuaded by Colin Catto from BCT. To make a
frequency division detector, Ithought well, why not
incorporate hips nine as well.
And so put one channel frequencydivision one channel heterodyne.
And it came out quite well. Sothat became the duet. The
(12:55):
backbox three was better atheterodyne because it had a
massive speaker in there. And itwas you could run groups of
people. I've got letters frompeople saying I had two or 300
people in my back walk and onlyone detector. It was about books
three, but they could all hearit you see. So that was very
good for walks and talks andthings. But for closers study
(13:19):
people needed to recordfrequency division so they could
look at the thing and actuallyevidence the fact that they'd
seen a 45 Pip. Because with arecording, because if you've
tuned into about detectingyou've got no way of registering
where you're tuned in. So youcould say well, that's a 45
(13:41):
kilohertz pitch, we can say it'sa 55 It couldn't prove it. But
with frequency division, howevercrude it was, you could say you
could show a sonogram of thedifferent pitches. So that was
the first time people couldprove what they saw. And it
started being adopted by moreprofessional bat interest
(14:04):
people.
Steve Roe (14:07):
And was that overall before you sold stock
electronics? Was that the mostpopular detector that you're
making at the time?
David King (14:15):
Yeah, it was the stagger looked electronics
evolved into backbox. Limited.
Later on, I thought well, Ican't call it stag electronics
if I'm not in St. tagless. Sowhen I moved to Sussex who
became backbox limited, samedetectors we were carried on
selling the black box threes, Ithink must have been 10 or
(14:39):
12,000 of those worldwide andthey used to go to every corner
of the planet really. I wasconstantly surprised by how many
how many people from remoteplaces heard about it and asked
about it but Get the blackboxthree, then was replaced by the
(15:03):
duet or not replaced, I keptthem alongside one another for a
little while then then stop thethree. The duet came out. Then
somebody said, Well, after doinglots of bat walks, somebody
said, Why don't you produce onefor children. So I produced the
(15:23):
micro bat, which was based onthe same technology as the bat
is where you could just switchfrom one centre frequency to
another, which made it easy. Andthen you didn't get people
breaking off the tuning knobs,which they did on bat walks. And
it was more of my own. I didn't,although I was earning a living
(15:46):
doing it. I was more interestedin doing it for the benefit of
the people that were interestedin bats. And most of my own
survey work because I startedsurveying at 990. Really, I was
first licenced in 89. I got someBob Stebbings correspondence
(16:07):
here. This is when he first sawthe bat box three. And
Steve Roe (16:13):
like say, he says, I saw the instruments at
Liverpool. So they really wereflying around the country about
them when they at the moment Ihave all of the bat detectors I
need, including the new minitwo, and stress that will be
getting reviewed by experts.
It's really nice to see all thishistory here, isn't it? So I
David King (16:30):
think I must have sent him one to look at. Because
he did ask to review one. He waskind of the guru at the time. So
I I was quite keen on hisopinion of it. And there we are.
There's a letter from Phil, whotalks about the QM C's Well, QM
(16:51):
C stands for Queen Mary College.
Pi Professor Pi was buildingthem the the famous professor
pi, because before that theywere all huge, great devices
that you had to close downsomewhere. Hold gates and things
like that.
Steve Roe (17:09):
Go Yeah, I was gonna say we've last series, we went
over to the British Library.
They've got an exhibition out atthe moment. And part of it is
Batson. They've got Holgate ondisplay. It's a massive thing.
This is really interesting. Sothis review from Phil is saying
the latest QM C mini Scott's atransparent purse best disc with
all the frequencies printed onthat rotates over small elite
(17:32):
led and this is where hesuggested replacing the black
twist knob with a combined discwhich is the version I've
written this BB three I've gothere has a transit a small
transparent desk with all thefrequencies printed on
ingeniously
David King (17:48):
you can think feel for that.
Steve Roe (17:50):
Yeah, we use those minis in douche bag away quite a
lot for backlogs and they wentdown really well. It was dead
easy to say switch between thered, the red, I have the notch
on the green light to the pitchlight. It was really simple.
microbots on the micro batch.
Really simple design. Yeah.
Yeah, they went down reallywell.
David King (18:08):
I was gonna say, because when you do bat walks,
you have to introduce peoplewho've never heard about before,
to what they sound like and whatthey do. And the kind of
detectors that are around noware more focused on recording
and not producing a sound forpeople to listen to, like,
Steve Roe (18:31):
like you say the technology is moving on that
it's all based on a visual cue.
What, what's your view of that?
And does it matter that we'regoing to lose that field skill
over time?
David King (18:43):
Well, my view is that we, we shouldn't lose that
skill. Because it comes alongwith other things, the cheers of
bats and things like that. So ifyou rely totally on technology,
you're you're as vulnerable asthe battery. Basically, if your
(19:04):
battery went flat, you're not asurveyor anymore. So just
somebody's looking at blackthings coming out of a race. But
you can identify a lot of batsby ear with heterodyne and even
time expansion. But you canidentify bats quite easily with
(19:24):
that, because you hear frequencydivision in one year. And
immediately after that timeexpanded episode. And I could go
around and recognise a lot ofspecies apart from some of the
migratory species and of course,just just with time expansion,
(19:45):
because you do get your ear inand you can hear the difference
between four and a halfkilohertz and five and a half
kilohertz by ear quite easily.
Steve Roe (19:54):
So what's your view of the current batch set to
market them?
David King (19:57):
Well, I hope it gets better. I think the sound
quality has gone down, you know,because people are more
interested in the the visualexperience afterwards and in the
office or whatever. Or evenworse than that. They're
interested in what the computertells you.
Steve Roe (20:16):
That I mean, it's always a contentious question,
what is your view of auto ID,then?
David King (20:21):
Well, it's getting there, it's a little bit better
I use it myself for where I'mteetering between one or another
species. I think, well, I'll runit through this and see what
they think. Yeah. And becausethey're drawing on lots and lots
and lots of increasingly moreexamples now, coming down with
(20:42):
decisions between pecotasororitas and Curtis austrack.
Yes, and those are the things Ithink I'm a bit sceptical about,
you know, I can't believe thatthere is a clear cut. And you
see on the screen, it says, oneminute, it's Lakota authorities.
(21:03):
And the next call is awestruck.
Yes. And you think well, ifthey're able to overlap like
that, it's going to bedifficult. So for running
through a whole 1000 files, isgoing to give you a pretty good
idea of what's the
Steve Roe (21:19):
what's your favourite bat call or bat encounter when
you've been recording bats overthe years if you've got a
favourite memory.
David King (21:28):
There are so many of them. Yeah. The one of my
favourites was, I stopped at apetrol disused petrol station in
corn on the way to Cornwall, andI could see Sarah teens catching
me bugs just in the canopy. Andso I stopped and got the
(21:49):
detector out. They weren'tdeterred at all by that. And
watch them really close catchingthese may bugs, you could see
the Beetle in the mouth as theyflew off because they came out
quite early to catch these. Andthat stuck in my head because it
was quite an experience. It waslike a display, especially for
(22:10):
us, which we just sat there andwatch them doing this. Really
close quarters, I suppose inAfrica, in the Kruger National
Park, we caught some gianthorseshoe bats. We had a look at
them as well. This was early onand I had the backbox three
(22:32):
there. So we were able to hearwhat they sounded like. And they
were echolocating. At somedistance, you couldn't pick them
up with the with the backbox.
Three, but that was a verysensitive detector. Anyway, that
one. Yeah. I used to test it inthe early days, but by dropping
a pin up the path and a garden.
(22:52):
And you could hear it right bythe back door.
Steve Roe (22:56):
I remember on a field trip a man to graduate degree we
went to Borneo for a couple ofweeks and took this detector out
with me. And it was stillshooting to fortify for UK.
pipistrelles and switch thisdetector on and within seconds
could hear a horseshoe. And itwas that was like
David King (23:14):
Oh, which which horse he was, I don't
Steve Roe (23:16):
know I need to go.
I've never looked at the book Ineed to kind of look I can't
remember and didn't know at thetime. But it's quite a few out
there seem to remember. Luckily,
David King (23:25):
in Britain, if you're making a bat tape, it's
easy, because we've only got afew species. But you go
somewhere like Africa and or thetropics recently went to Costa
Rica. And there are so many batsthere. I'd have no idea what
they were listening for them. I
Steve Roe (23:46):
mean, that bat tape and CD did the bat detective,
again, got a copy of that. Andthat's how I learned back calls.
And you did and like you say itwas about the sound and
listening to the rhythm and thetonal quality that's an that was
really useful for me when Briancome into the story.
David King (24:05):
Brian and I used to do talks and early back detector
workshops in the 90s, early 90s.
And I talked about the detectorsand he talked about the biology
etc. And we then we go out anddo listening. So that's how I
got to meet Brian
Steve Roe (24:24):
making bad sectors then and and your background as
a musician has taken you allover the place. Really I guess
you've specialised in handhelddevices technology now means
that we've got static remoterecording detectors that go out
and record 1000s and 1000s ofbackdoors. How do you deal with
the storage of backhauls at themoment?
David King (24:42):
I don't collect them anymore because they're, you
know, I haven't got that manyyears left in my life to look
through them all. I mean, it'slike my record collection. I've
got CDs, music CDs, so many ofthem And I think that, you know,
even if I sat down now andlistened for the rest of my
(25:04):
life, I wouldn't get throughthem. Yeah. So you've got to
prioritise. And so I don't, Idon't I don't collect calls
anymore, except if they'respecial, you know, if it's
something really unusual, we'recurrently
Steve Roe (25:19):
seem to be in an era of night vision, thermal, and AI
is the hot topic of the moment.
technology's changing at suchpace. How do you think that's
going to influence how surveysfor bats are done? And we're
just going to become techniciansas these technologies put up a
barrier and put up a barrierbetween us and the bats? I
guess? Yeah,
David King (25:39):
well, they already, surveyors are dividing into two
types, really, you get the typethat the ecologists that are
interested in the biology inthe, in the, the actual animals,
and you've got the professionalsthat just want to do the job,
you know, just find out how manybats are there and what species
(26:03):
they are and, and what they haveto do. So you can approach it
either way. But I prefer thefirst because you actually
experience more. But you can besat in front of a computer all
day. Otherwise, I've put backdetecting in, in to perspective
now because I do so many otherthings. In France now. And that
(26:29):
detecting is just one of thethings but I'm pleased when
people come and say, Oh, tell meabout the bats and they can talk
about them.
Steve Roe (26:36):
Okay, we haven't even touched on the fact that you've
got house over in France and yougo there all the time. What sort
of stuff you got over in yourgarden there.
David King (26:43):
We've had up to 11 species going through the garage
alone. Great horses greatermouse heated, less a horseshoes,
long pluck Otis orators andaustrack es Jeff Roy's three
three kinds of pips, but theydon't have the soprano where we
(27:05):
are Barbra styles sells quitecommon. Yeah, that's with the
bats. But other creatures. Wewe've had a black stork in the
field next door. Golden Orioles.
Regular hoopoes. That's right.
(27:25):
Turtle there. turtledoves. Owls,all sorts of owls, badgers
foxes. And we've got Ragon downin the river at the bottom of
the garden. So we do get to seea lot of stuff there. And every
time we go, we think wow, lookat that moth. Giant emperor.
And, and we get 1000s of moths.
1000s. But I love it there. It'slike It's like England that it's
(27:53):
in Normandy, but it's it's got alot more wildlife a lot more
insects.
Steve Roe (28:05):
One final question I have, why are bat detectors
always in black cases make themreally hard to see why did no
one ever make something that wasin a different colour? Is it
just what was available at thetime?
David King (28:17):
No. Well, when you sell a detector, you sell it in
the daytime. And, and all thatall the sophisticated equipment
was black in those days.
Steve Roe (28:30):
It's been fascinating talk to you, David became Thank
you very much.
David King (28:33):
You're welcome.
Steve Roe (28:36):
A huge thanks to David for taking the time to
give us that fascinating historyand insights. And David, if
you're listening that bottle ofFrench wine you sent me away
with was delicious. We've put alink in the show notes to the
BakBox detectors website as wellas the detector advice pages on
our own website. So if you'dlike to find out more, check out
the links. We'll be back in twoweeks time with the landowner of
the largest number of bat roofsin the country. Catch them
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