Thousands of Flying Foxes Go "Missing" in Australia

Stephanie Peatling in Sydney
for National Geographic News

September 26, 2006

Thousands of spectacled flying foxes apparently took flight when Cyclone
Larry flattened far north Queensland, Australia, in March.

(Related news: "Cyclone Larry Devastates Australian Towns, Crops; Second Storm Approaches" [March 21, 2006].)

Now zoologist Louise Shilton has turned detective in an attempt to discover where the fruit bats have gone and exactly why they fled.

Shilton, who works for Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) in Atherton, says that the bats' numbers for this time of year are as much as a third lower than they have been in previous years.

"I've heard numerous reports from residents who were holed up in their properties near well-known [flying fox] camps," Shilton said.

"They said [the bats] took flight en masse at three o'clock on the Sunday afternoon," the day before the cyclone hit the mainland.

Normally animals fleeing an unusual weather event can sense a drop in air pressure and head toward a safe area further inland, Shilton says.

But on this occasion the flying foxes acted out of character.

"The foxes took flight, and the really peculiar thing is they headed toward the cyclone, toward the coast," she said

Another peculiar phenomenon happened about a week after Larry, when large numbers of flying foxes were also spotted leaving their camps about three months earlier than they would normally begin their winter migration.

Scientists estimate the region is missing tens of thousands of the bats, and no one is sure why.

Lack of Food

The spectacled flying fox is one of four flying fox species in Australia (watch related video of Australia's black flying foxes).

The species is the only one of the four that is confined to a specific region, the tropical rain forests of northern Queensland (map of Australia).

Shilton is asking local residents to report sightings of the flying foxes to her research team in an attempt to find out where the creatures have gone.

Although she believes that some bats would have died in the cyclone, Shilton remains optimistic that not all the missing animals are dead.

"I went around sites a week after [the cyclone] went through and didn't see evidence of mass mortality," she said.

But, she says, the animals that stayed in the region are being hurt by lack of food.

The storm destroyed many of the blossoms and rain forest fruits that flying foxes eat, forcing the bats to alter their normally nocturnal habits.

"They are feeding in the daytime, which must be a case of animals thinking, If I don't eat this now, I might not get anything," Shilton said.

The bats are also staying in one area for days at a time instead of returning to their camps, presumably settling near food when they find it.

Storm's Casualties

Steve Turton, director of the Tropical Landscapes Joint Venture between CSIRO and James Cook University in Queensland, is overseeing research into the environmental impacts of Cyclone Larry.

Although the flying foxes are struggling to find food, Turton says, other animals seem to have coped with the storm's devastation.

Tree dwelling, leaf-eating species such as the tree kangaroo and the ring-tailed possum were found to be quite resilient.

"The foliage came back quickly," Turton said. "A lot of trees were only partially defoliated, so the animals just moved to the other side."

Not so fortunate were the southern cassowaries, a rare flightless bird.

Their main food is fruit, one of the primary casualties of the cyclone.

Australia's National Parks and Wildlife Service has set up 35 feeding stations to help keep the small population alive.

But the agency may have to keep feeding the birds for up to two years until trees and shrubs recover sufficiently to bear fruit again.

"It's a real dilemma, because some [of the birds] will miss out, so there will be fatalities," Turton said.

The cassowaries "have had to make their own paths, because there are dead branches everywhere, so they are coming out on the roads to walk around," he said.

"They are not very intelligent … and they don't understand walking in front of a truck means you get squashed. We have had 12 fatalities since the cyclone."

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