QUT researchers are using drones and infrared to measure koala populations.

The innovative koala-detecting method appears to be more reliable and less invasive than traditional animal population monitoring techniques.

Researchers designed the system by correlating the detection of koalas from the air using ground surveys of tracked radio-collared koalas in Petrie, Queensland.

The system uses infrared imaging to detect the heat signals of the koala despite the canopy coverage of the eucalyptus trees.

“Nobody else has really managed to get good results anywhere in the world in a habitat this complex and in these kinds of numbers,” says Dr Grant Hamilton, from QUT’s School of Earth, Environmental and Biological Sciences.

To maximise the effectiveness of the technique, the researchers carried out aerial sweeps of the area at early morning during colder months, when difference between the body heat of the koalas and the background was likely to be greatest.

The drone covered an area in a “lawnmower” pattern, going up and down over a specific area.

After the flight, the data was put through an algorithm that was designed to identify the heat signatures of the koalas compared to other animals in the area.

Because the researchers were able to confirm the location of the koalas detected by the drones with the location of the koalas determined by their GPS tags, they could rate the accuracy of the system.

“On average, an expert koala spotter is going to get about 70 per cent of koalas in a particular area,” Dr Hamilton said.

“We, on average, get around 86 per cent. That’s a substantial increase in accuracy that we need to help protect threatened species.

“What we previously found was the accuracy was about the same as expert observers.

“Now we actually know that it's better.”

Animal detection by drone is also quicker and cheaper than using human spotters.

“We cover in a couple of hours what it would take a human all day to do,” Dr Hamilton said.

“[But] there are places that people can’t go and there are places that drones can’t go.

“There are advantages and downsides to each one of these techniques, and we need to figure out the best way to put them all together.

“What we do know now is that this is a really powerful tool within the tool box.

“Thinking about any one of these approaches as a silver bullet tends to make people complacent – they think the problem has been solved, so let’s move on. Koalas are facing extinction in large areas, and so are many other species and there is no silver bullet.

“This is a powerful technique in the right circumstances.”

The team is now working to improve the accuracy of its system and adapt it to be used to detect other invasive species such as deer.

Their latest paper is accessible here.