Using high-definition cameras and GPS-mounted navigation software, drones can cover a much larger amount of territory than ground-based crews, said Serge Wich, professor of primate biology at Liverpool John Moores University. "To do several line transects to count orangutang nests would take us three days," he said. "A drone can do it in 20 minutes."
Drones can also be used to spot smoke from poachers' campfires and work at night to help prevent surprise encounters between rangers and poachers, or rangers and each other. "Friendly fire" incidents have actually led to gunfights and deaths between rangers who were working at night.
Perhaps most importantly, the new generation of lightweight and easy-to-operate drones are inexpensive enough for cash-strapped African governments to afford.
Wich is testing one built by a Swiss firm that only costs a few thousand dollars. The drawback is it only has a flight time of about 45 minutes and needs a landing area of at least 100 square meters.
The poachers in Chad were actually part of an armed militia group of 40 to 50 men on horseback who were conducting raids to ship ivory to Asian markets.
Stopping that kind of force would need a much bigger drone with a longer flight time, and a much bigger military force on the ground, Allan said.
He hopes Western nations may see the value of protecting both wildlife, as well as the borders, of nations from armed terrorist groups such as Al-Qaeda, whose presence has grown recently in parts of Africa.
"You would need several vehicles at a million dollars each," Allan said. "Not just to protect elephants, but to protect their borders from these raids by these militants. That's a stronger incentive for combined use."