Doing the numbers drives volunteers batty
IT IS hard to work out where the racket is coming from among a rustic clump of stringybarks in Centennial Park. Then the black blobs hanging from the branches become visible: a colony of perhaps 1000 grey-headed flying foxes has set up camp, chirping, screeching and wriggling their way through another misty morning.
''What you can hear are alert calls, babies calling to their mothers, and territorial calls as well,'' said the CSIRO ecologist Adam McKeown. ''At this time of year, males are just starting to establish territories, younger males are play fighting with each other.''
It's census time for flying foxes, as scientists try to work out how vulnerable the species is. Though listed as protected, it has been eight years since a survey was completed, and not all bat colonies, known as ''camps'', were studied at the same time.
Jane DeGabriel, left, and Deb Stevenson monitor the bats in the park lands. Photo: Peter Rae
Starting on Thursday, a three-day national effort involving hundreds of volunteers from NSW, Queensland, Victoria, South Australia and the ACT will all count bats using the same method, and be repeated every three months over a four-year period if funding continues.
It should show whether the best estimate of between 300,000 and 400,000 remaining bats is accurate, and whether the population is in serious decline, as other studies have found.
Some experts have said the species, so often maligned as messy, noisy nibblers of fruit trees, could be ''functionally extinct'' in the wild by 2050.
Endangered or nuisance? … a flying fox in Centennial Park Photo: Peter Rae
Part of the problem is flying foxes are notoriously mobile - colonies constantly reform and move - and bats can travel up to 120 kilometres a night to forage for food.
''Bats move around - these animals here in Centennial Park might be in Gordon tomorrow,'' said Jane DeGabriel, a programs and policy officer with the NSW Office of Environment and Heritage.
Ms DeGabriel was undertaking a training program before the census, being run by the CSIRO, to ensure bat watchers across eastern Australia will all use the same counting methods.
There are thought to be roughly 300 grey-headed flying fox camps in eastern Australia and researchers plan to measure as many of them as possible between Thursday and Saturday.
The program is supported by the NSW Environment Minister, Robyn Parker, who promised that the state would commit resources to the full four-year study.