Is the flying fox a cute, intelligent mammal in need of protection, or a devastating pest that should be shot?
This is the emotional debate that’s raging between fruit growers and conservationists in Queensland over the spectacled flying fox fruit bat. Both sides are uncompromising. For growers, the bat colonies are out of control and ruining their livelihoods. But the conservationists say the bat populations are vulnerable, and if farmers can’t continue growing fruit without killing the bats, they should stop farming.
So who’s right? Currently nobody knows. Both sides depend on highly dubious population figures, based on visual counts. Science has been called upon by both sides to provide some hard facts.
The appropriately named Sam Fox at James Cook University in Townsville is starting the first study to provide the hard biological data needed to assess the true state of the bat populations and reproductive life cycle. This should help to identify any at risk colonies, and determine what, if any, are sustainable cull levels.
But one side in the debate will lose – how will they handle the truth?
Narration: Every night they come out to feed, swarms of hungry bats – devouring millions of dollars of fruit. In North Queensland farmers are shooting them out of the sky in a desperate attempt to save their crops.
NEWS GRAB: As you can see here they’ve just come in and eaten all the fruit on the top down to here. And just left the fruit that’s lower towards the ground.
Narration: The problem has become so bad, tried everything to stop the flying foxes, including electrocution, shooting them, even netting entire orchards. But conservationists like Jenny Maclean want the killing to stop.
Jenny Maclean: One farmer was killing up to 10,000 in one lychee season. Now that’s 10,000 out of a total population of 200,000. I mean it’s not sustainable.
Narration: But farmers like Shane O’Connor don’t agree with Jenny’s figures, they say if anything the bat numbers are on the rise.
Shane O’Connor The evidence on the ground suggests that their numbers are actually increasing. Certainly the damage is increasing and yet we’re being told that they’re in danger.
Narration: Now science has been asked to step in to try to resolve this ten year battle. At stake are the farmers’ livelihoods and the survival of this native Australian bat the spectacled flying fox.
Sam & Paul: Look at them all, have you an idea how many flying foxes are in this colony?
Narration: With tension running high both sides have turned to this scientist, bat researcher Samantha Fox.
Samantha Fox: My project was devised to try and find some hard data to help towards solving the problem between the fruit farmers and the flying foxes. It is a difficult position to be in. I have the conservationists on one side, I have the fruit farmers on the other, but I would like to think that I will be able to keep both of them happy, maybe.
Narration: Till now, both sides have been arguing over just how many bats there are. And the bat supporters say - not enough. Jenny McLean runs the Tolga Bat Hospital.
Narration: She sees the damage first hand, spectacled flying foxes killed or injured by farmers. This is one that’s been shot – you can see it’s injuries… many traumas, but mainly barbed wire.
Jenny Maclean: I think there are very few people who would dispute the fact that the numbers are going down, it’s just the rate at which they’re going down and what the absolute figures are.
Narration: So far the bats supporters have been winning. They’ve won a battle to ban the high voltage electric grids the farmers use to kill flying foxes. And the federal government has declared the spectacled flying fox a vulnerable species. But for Shane and other farmers these decisions were based on unreliable counting methods. Most population estimates are based on volunteers standing beside bat colonies counting them as they leave.
Shane O’Connor: Have you ever seen flying foxes fly out at night? I mean how on earth could any sensible person say they can accurately count them. I know they say they can, but it’s a load of rubbish, we need to get some science into it. We need to find out really what’s happening.
Narration: Watching the bats fly out, it’s easy to see why there’s been so much disagreement over bat numbers.
Samantha Fox: It’s not easy. The most common way of censuring flying foxes is to count them as they fly through a natural framework on the horizon. But you can’t do it with one person, you need a number of people.
Narration: But it’s not just difficult to count the bats. In the dark it’s almost impossible to tell one species from another. Common black and red fruit bats are easily confused with the species at the centre of the fruit farmer’s troubles - the spectacled flying fox. And that’s why Sam’s using a new approach. She’s not just counting numbers, she’s building a population profile to find out which colonies the bats come from. And that starts with examining the bats DNA fingerprints.
Samantha Fox : By fingerprinting individuals from the farms and fingerprinting individuals from the different colonies hopefully we will be able to trace those raiding individuals back to what colony they come from.
Narration: Eventually she’ll build up a bat map of North Queensland. It will tell farmers whether they’re just killing local bats or those from colonies all around Queensland as well.
Samantha Fox: The fruit farmers want to know whether if they removed the colony that’s next door to their farm whether that will remove the problem basically.
Narration: But DNA profiling alone can’t answer the big question - how many bats can the farmers kill without placing the speckled flying fox at risk.
Narration: DNA can tell you where a bat’s come from but to understand the dynamics of that population you need to know the age of those bats. And we get that information straight from the bats mouth. Or more precisely their teeth. They contain the clues to how long the average fruit bat lives.
Q: What are you looking for in the teeth?
A: What we are looking for are growth layers in the teeth… So if you look at this figure here…. These bars are the growth layers that we are looking for. Sort of like growth rings in a tree.
Narration: By studying the bats lifespan Sam can work out how long a colony would need to recover from any cull. It’ll be 2 to three years before Sam gets any meaningful results. If she finds that spectacled flying fox populations are at risk, it will add to the pressure from conservationists to ban bat culling altogether. And that could put some farmers out of the business.
Mark Panitz: If we stop culling, farmers will go to the wall.
Narration: But science could also put bat lovers like Jenny on the loosing end of the debate.
Jenny Maclean: If the evidence stacks up that there are too many flying foxes, that there is a non-cruel method of culling then you know, that’s it really.
Narration: Sam’s job won’t be easy. But in the battle between farmers and the environmental lobby science is on her side.
Sam Fox: I have to maintain a middle of the road unbiased position which is not always easy to do, but at the end of the day the facts will stand up for themselves and the facts are the facts.
Reporter: Paul Willis
Producer: Naomi Lumsdaine
Researcher: Paul Grocott
School of Tropical Biology
James Cook University
Townsville Qld 4811
PH: (07) 4781 4737
Fax: (07) 4725 1570
Qld Fruit & Vegetable Growers
Rocklea Qld 4106
PH: (07) 3213 2444
Tolga Bat Hospital
PH: (07) 4091 2683
- FLYING FOX FIGHT (15/08/2002)