Night flight: VicForests drones’ thermal cameras to spot greater gliders

Drones with thermal cameras are being used to quickly pick up Greater Gliders in timber coupes. See the footage.

VicForests is trying to end the controversy over inadequate surveying of its timber coupes by using night-flying drones to spot greater glider possums, owls and other species using thermal cameras.

Last November Supreme Court Justice Melinda Richards ordered a halt to harvesting until the state-owned native forest timber manager resurveyed most of its coupes to protect greater glider possums.

VicForests and former Department of Environment, Land, Water and Planning staff had been using spotlights to survey kilometre long transects of potential coupes for gliders, along existing roads, where possible.

But in the case brought by Environment East Gippsland against VicForests, Justice Richards ruled it “must survey the whole of any coupe proposed for harvest which may contain glider habitat”.

The order brought timber harvesting to a halt and left VicForests struggling to identify how it could resurvey a whole coupe without putting its staff at major risk of injury as they stumbled through the forest in the middle of the night trying to spotlight possums.

Ultimately the VicForests’ team hit on the idea of using drones fitted out with thermal cameras to detect what its spokeswoman called “hot spots” when flying over the forest canopy at night. 

Once a hot spot is identified the drone switches to a normal light video camera and spotlight to zoom and enable the species to be identified. Details of location and images of the animal are then recorded.

Trials have already been conducted at Marysville, where about 20 greater gliders were identified and 10 sites in the Wombat Forest, where mostly ring-tailed possums were found.

VicForests ecologists say the drones, which have an effective range of 500m, can survey a 30ha coupe in three to four hours, along 50m wide transects. The drone survey is then repeated twice more to ensure it is comprehensive.

“In easy conditions we can do 100ha in a night,” a VicForests ecologist said.

One ecologist said trying to meet the court order of surveying a whole coupe on foot, would have been impossible.

“It would have taken 30 person nights to complete the average 30ha coupe,” the ecologist said.