Bat Hang-out Causes Problems for Local Melbourne Gardens
The city of Melbourne, Australia contains a number of botanical gardens. It turns out native bats in the area think these gardens make for a perfect home. But local officials think otherwise. So they’ve embarked on a plan that includes convincing the bats the living is easier elsewhere. Sandy Hausman reports.
CURWOOD: Melbourne is Australia’s second city, a center for fashion and the arts. It’s home to more than three million people and to a colony of thousands of flying foxes, a type of giant bat that’s taken up residence in the city’s lush botanic gardens. Australia’s population of grey-headed flying foxes has been in decline. So officials there have declared them a threatened species. Still, in Melbourne, the municipal gardeners say there are far too many, and they’ve hatched a unique plan to drive the big bats away. Sandy Hausman has details:
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HAUSMAN: Melbourne is one of the fastest-growing cities in Australia with more than 4500 new residents arriving each year. It’s a flat, sprawling place of highways and high rises. Farms and orchards on the outskirts of the city are quickly turning into housing developments, and the bats which once fed on blossoms and fruit in the country are now becoming city dwellers.
TOOP: These are grey-headed flying foxes and some people refer to them as fruit bats.
HAUSMAN: Simon Toop is with the Australian Department of Sustainability and Environment. He’s standing in a dark, damp corner of Melbourne’s Botanic Garden called Fern Gully. In other parts of the park, visitors find rolling green lawns, tidy flower beds and elegant old trees from England, but Fern Gully is overgrown with tropical plants and overrun by bats. They soar overhead – their large, black wings silhouetted against a warm spring sun. They hang like black Christmas balls from every tree, chattering and squabbling to protect their turf:
|(Photo: David Williams. Courtesy of Ku-ring-gai Bat Conservation Society )||
TOOP: We have four species of flying foxes that are endemic to Australia and they’re a large bat, one of the largest. They have a wingspan of up to one meter. They have a heavy cover of fur that stretches from their ankles to the tip of their nose, and their head’s grey as the name suggests.
HAUSMAN: The resident colony of bats – those living in Melbourne year-round – is about 8,000, but each spring as the animals prepare to mate and raise young the number grows. In 2001 there were about 20,000, the following year 25,000, and now there are 28,000 bats literally hanging around the trees. They pose no threat to human health but ecologist Toop says they’ve taken a toll on several trees that have grown in the public gardens for more than a century.
TOOP: By moving up and down the branches and by flying in and out, they are actually breaking the branches, stripping leaves. They were fouling the paths, especially during breeding season. They can have quite a pungent smell, which is an odor to attract mates, of course, so there was some controversy there.
HAUSMAN: At first, gardenkeepers tried using a sprinkler system to chase the bats away. They put fishing line in the trees and made loud noises. The bats were not impressed. The government then hired sharp shooters to visit the gardens and cull the flock, but that outraged animal rights activists like Debra Tabart.
TABART: Here we have one of the most majestic animals on the planet who has been vilified because it’s a bat and the Dracula movies and the whole thing. If you ever meet a flying fox face to face, they are the sweetest, cutest animals you’ll ever see.
HAUSMAN: The hunt was abruptly cancelled. Officials wouldn’t say how many flying foxes they had killed – perhaps because animal rights activists threatened to kill one tree for every bat that was culled from the colony. Now, the Department of Sustainability and the Environment has joined forces with several other agencies to try a different approach – building a new habitat about five miles from the gardens in a traditional bat flyway along the Yarra River. The state of Victoria has set aside a million dollars to remove non-native vegetation from the 10-acre site, then plant native trees and ground cover, install sprinklers and build a large cage where captive bats are kept.
TOOP: We have in there at the moment approximately 80 flying foxes, so we’re, hopefully, trying to capitalize on the gregarious nature of the species and the highly social nature of the species to attract them out there using the captured flying foxes – their smells, their sounds – to attract their friends.
HAUSMAN: To create the impression of an even larger colony, they’ve taken leaf litter from the botanic gardens and moved it to the new habitat at Horseshoe Bend. Food has been provided, recordings of large bat colonies play over loudspeakers, and plastic bats hang from artificial roosts installed to serve the flying foxes while newly-planted trees are growing.
TOOP: It’s become quite a social gathering place where they’ll come and meet and hang out with the decoys.
HAUSMAN: The problem is that passers by only visit, they don’t stay. So officials are getting more aggressive. Back at the botanic gardens they’ll fire starter pistols, blow airhorns, release balloons, wave flags and do other things calculated to annoy the bats. Animal activist Deborah Tabart says these tactics will stress the bats, but won’t work in the long run.
TABART: [LAUGHING] No, I think some of the bats might get slightly confused for a few days, but they’ll go home.
HAUSMAN: She’s skeptical about the need for bat relocation, pointing out that flying foxes live in a relatively small part of the gardens – on less than two and a half of the 100 acres – and she questions the campaign’s priorities:
HAUSMAN: I think it’s ill-conceived, and I see this all the time – short-term, silly logic and not understanding the big picture. And a lot of those trees are actually not Australian natives, so they’re saying this is protecting our cultural heritage. The bat is our cultural heritage. The pine tree that came from England is not, in my view.
HAUSMAN: In Sydney, the World Wildlife Fund fears this program could be bad news for other animals. If officials term bat relocation a success, the organization says communities all over Australia might begin to harass troublesome creatures to make them move on. It would be better, they say, to educate the public, to encourage tolerance and to plant more trees. Tabart agrees, adding that the government should promote the bats of Melbourne as a tourist attraction encouraging visits at dusk when thousands of flying foxes head out to feed:
TABART: If I was the government, I would say, “Come to Victoria. Come and see the bats lift off,” and then have a cup of tea afterwards.
HAUSMAN: Already the bats draw some visitors to the botanic gardens where they express support for the grey-headed flying fox.
MALE: I reckon they’re pretty good. I like the bats. They’re pretty groovy. Yeah, they’re a nice creature!
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FEMALE: They don’t frighten me. They just sort of keep to themselves, I guess.
MALE 2: I reckon they’re alright. They’re just part of the garden. What’s the worst that can happen? They can always pooh on you but that’s about it.
MALE 3: I’m a fan of them. There’s a bit of a stench but I can handle that.
HAUSMAN: Simon Toop agrees the flying fox is a magnificent animal but insists a program is needed to protect the trees. He’s not sure relocation will work but says the Department of Sustainability and Environment plans to give it time.
TOOP: This has never been tried anywhere in the world before so essentially, we’re making this up as we go, of course in consultation with flying fox experts and other wildlife biologists. We’ve given ourselves two years to review the project, and if we consider it’s worthwhile, we will continue for a further one year.
HAUSMAN: There is, of course, the risk that bats will relocate – not to Horseshoe Bend but to suburban backyards. Officials say that should not be a long-term problem since flying foxes prefer large areas of dense vegetation near water and will soon move on in search of more suitable camps. The government has, however, established a hotline residents can call if a bat hangs around for more than a week or if a flock of more than 50 should take up residence. For Living on Earth, I’m Sandy Hausman in Melbourne.
[BIRDS, BATS CHIRPING AND CACKLING]
MUSIC: [Portishead “Sour Times” DUMMY (Go! Discs Ltd. – 1994)]