Wildlife biologists have put drones to work counting whales, checking bird nests, and nabbing poachers. Now, they’ve designed a drone that can hover within fast-flowing swarms of bats as they zip across a darkened nighttime sky.
The drone—or “Chirocopter” (named after Chiroptera, the scientific name for bats)—is equipped with a microphone to record echolocation chirps (sounds that bats use to navigate) and a thermal camera that can “see” bats by detecting their body heat. Similar technology has been used to record bats from the ground and from towers, but the Chirocopter has an advantage because it can be placed anywhere in 3D space, the team reports this month in Methods in Ecology and Evolution.
Case in point: The team deployed a Chirocopter outside a cave in New Mexico that is home to about 800,000 Brazilian free-tailed bats. Just before dawn, the bats form dense aggregations and return to the cave along a chaotic aerial “freeway” at speeds exceeding 100 kilometers an hour. The team maneuvered the Chirocopter to hover in the middle of the fast-flowing swarm for 84 minutes at heights ranging from 5 meters to 50 meters—and there were so many bats that the scientists recorded 46 echolocation chirps per minute.
The researchers hope that after returning to the cave to get more footage and recordings, they’ll be able to figure out how the fast-flying mammals avoid colliding with one another. Chirocopters could also be put to work in other places to study how bats move around wind turbines and other humanmade structures. (No bats were harmed in the testing of this technology—they all swerved to avoid collision with the Chirocopter.)