Our bat lady, Dr Lindy Lumsden, has helped developed a new piece of software that makes it easier to find out about how many bats are about. She uses a bat detector to record calls from a site over one evening. It records sometimes thousand of calls. If she were to go through and count and identify each call this would take months, but the new software can do it in a matter of seconds.
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Narration: I’m on the hunt for some amazing and elusive little creatures. Although very common, they’re seldom seen and exceptionally difficult to catch.
Dr Paul Willis, Reporter: So, this looks like the sort of place that you’d come to?
Dr Lindy Lumsden: Yep, this looks like a great spot, let’s go over here and set it up.
Narration: It may look like a badly designed clothesline, but this cumbersome piece of equipment will hopefully help us to catch our quarry.
Dr Paul Willis, Reporter: After all this effort you wouldn’t want to lose them - so what do we do now?
Dr Lindy Lumsden: Now we’ll just leave it there until it gets dark and then we’ll come back later and see what happens.
Narration: A couple of hours later and our creatures of the night emerge.
Dr Paul Willis, Reporter: Let’s see if we’ve got anything.
Dr Lindy Lumsden: Oh yeah, we’ve got something.
Dr Paul Willis, Reporter: Oh, isn’t he gorgeous, isn’t he beautiful.
Narration: This is a microbat – one of the smallest bats in the world.
Most of us have never seen one, but incredibly they make up a quarter of all mammal species native to Australia.
Dr Lindy Lumsden: They’re just coming out at night, silent to our ears, hidden during the days in roosts. People are just oblivious that they’re even around most times.
Narration: Science knows very little about microbats, which is why Dr Lindy Lumsden has devoted the last 25 years to studying these elusive creatures.
Dr Paul Willis, Reporter: Now, the bats that most people know about are the big flying foxes, but this is a completely different group of bats isn’t it?
Dr Lindy Lumsden: Yes, these ones are predominantly small while the megabats are predominantly large.
Narration: Flying foxes, the type of bat we are all more familiar with, are megabats. They have a body length of up to 30cm. Microbats on the other hand have body lengths as small as 4cm, small enough to fit in a matchbox.
And only microbats have the gift of echolocation. They bounce ultrasonic sound waves off objects and create mental pictures of their dark surrounds with extreme clarity.
Dr Paul Willis, Reporter: So, if they’re echolocation is so good, they must have no trouble figuring out there’s a trap here?
Dr Lindy Lumsden: That’s the trouble, we only catch a small proportion of the bats, that come near the trap we only catch one in 10 of the bats that approach the trap.
Dr Paul Willis, Reporter: So there’s a whole hidden world out there of bats that we’re not tapping into?
Dr Lindy Lumsden: Absolutely, there’s a lot more bats out there than people realise.
Narration: And we’re going to go hi-tech to help see exactly what’s going on in the dark.
We’re going to use a thermal imaging camera, and hopefully we’re going to get images of some of the microbats that visit this tree every night.
We know they’re out there but even with an ultra-sensitive camera like this, the nocturnal wonderings of these small, swift and stealthy creatures, are incredibly difficult to follow.
Which is why Lindy collects data by tuning in on the microbats own wavelength.
Dr Paul Willis, Reporter: An elaborate looking setup you’ve got here, what’s all this?
Dr Lindy Lumsden: This is recording the echolocation call of the bats and downloading so we can see what the calls look like and identify the species while we are sitting out here.
Oh, there’s a bat flying around now.
Dr Paul Willis, Reporter: What are you seeing here?
Dr Lindy Lumsden: Okay, this is the frequency versus time, so this is the frequency of each of those pulses, this one up at 45 kilohertz it would be a tiny one, a little forest bat.
Narration: Until recently, the only way Lindy could tabulate her data, was by manually identifying the calls on the screen, a long and drawn out procedure open to inaccuracy.
So she teamed up with software wiz Matt Gibson to computerise the process.
Dr Lindy Lumsden: By the time you’ve collected data from a whole area you’ve got 30,000 calls and that might take me 5 months to analyse that manually, but using Matt’s program I can do it in a couple of days.
Narration: It works by identifying the species by the shape of the calls waveform, and then counting the number of calls, as many as a thousand a night.
Matt Gibson: There’s not many people who have Lindy’s level of expertise that can actually identify calls with the same level of confidence that Lindy can - and to get a program to do that is pretty challenging. Computers aren’t smart, they can only work with a set of rules and make decisions on that basis.
Narration: So, how do we know if it’s not the same bat flying around the tree a thousand times? Well, we don’t.
Dr Lindy Lumsden: It gives a quantifiable amount of bat activity. So it probably is not that important especially when you know there’s a 100 units of bat activity here and a thousand here, it’s still going to tell you what’s happening out there to some extent even if you can’t work out the number of individuals that represents.
Narration: This led Lindy to the discovery that there is much more microbat activity in our countryside than previously thought.
Dr Lindy Lumsden: Even though each one is really tiny, we now know that there’s a lot more bats out there than we previously realised, and with each one eating half to three quarters of their own body weight in insects, they’re consuming a large quantity of insects.
I think there’s probably a lot more insect eating bats out there than there are insect eating birds, and the bats are probably playing a much greater role at keeping the insect numbers under control.
Narration: The dynamic duo’s bat call recognition software is revolutionising the world of bat research.
Now it’s easy to find out what bats are around, making it more likely an accurate bat count will be included in faunal surveys.
Dr Lindy Lumsden: Often the bats are behaving differently to what birds are and what possums and gliders are so it gives us a greater picture of what the whole ecosystem is doing and not just one component of it.
Narration: And at the same bat-time the next night, Lindy tunes into the same bat channel – exploring the world of microbats few suspected existed.