Although aerial drones have already been used to count wild animals such as seals, doing so isn't that difficult, as the creatures typically lie right out in the open. Now, however, Australian scientists have successfully used the aircraft to count koalas that are hidden in amongst the leaves and branches of eucalyptus trees.

Led by Dr. Grant Hamilton, a team from the Queensland University of Technology started by equipping drones with infrared cameras.

Each of those drones was then flown in a "lawnmower" pattern, going in successive back-and-forth rows over an area of forest in which GPS-tagged koalas were present. The flights were conducted in the early morning during colder months, when the temperature difference between the koalas' bodies and the surrounding environment would be the highest.

After each flight, a custom algorithm was used to analyze the drone's video footage, identifying the number and location of koala-specific heat signatures. The accuracy of the system was subsequently assessed by cross-referencing the animals' GPS coordinates with the locations identified by the drone. It turned out to be significantly better than what is typically managed by ground-based surveys.

"On average, an expert koala spotter is going to get about 70 percent of koalas in a particular area," says Hamilton. "We, on average, get around 86 percent. That's a substantial increase in accuracy that we need to help protect threatened species."

What's more, utilizing drones is reportedly much quicker and thus cheaper than using traditional spotters. According to Hamilton, in two hours, a single koala-spotting drone can survey an area that would take a person all day to cover. That said, he believes that using a combination of drones and people on the ground, as dictated by the situation, will be the best way to proceed.

The scientists are now planning on covering larger areas with the drones, and on adapting the algorithm to identify the heat signatures of other species that they wish to track, such as invasive deer.

A paper on the research was recently published in the journal Scientific Reports. And in related news, scientists from Liverpool John Moores University have previously used drones to identify chimpanzee nests within the jungle canopy.

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