Quadcopters Go For a Better Bird Count

Ecologists are field-testing drones to record birdsong.

Drone studying birds
Drone with microphone and ecology students

Somehow it seems fitting: Ecologists are now using drones to record the chirping of birds.

A team from the Department of Environmental Studies at Gettysburg College in Pennsylvania bought an inexpensive DJI Phantom 2 quadcopter, hung a microphone at the end of a suspension line, and flew it into various songbird habitats. They then studied the recordings to count the number of songbirds in a given area, one way to track the dynamics of bird populations over time. These population counts have traditionally been undertaken by ornithologists walking through an area and relying on their ears alone. Researchers also put radio collars on birds, or take aerial photographs from both manned and unmanned aircraft. This study, led by researcher Andrew Wilson, was the first of its kind to use drones fitted with audio recorders.

Their results, published in The Auk: Ornithological Advances, carefully detail what they term “bioacoustics monitoring via UAV-mounted recorders.” Although this was just a proof-of-concept study, the technique is meant to help future researchers by reducing the need to travel by foot throughout rough terrain, steep slopes and wetlands.

The scientists started with a quadcopter and a “Zoom H1” digital recorder. They suspended the recorder from the drone using an 8-meter (just over 26-feet) line, flew at different altitudes around their campus, then compared what could be heard on the recordings to what they could hear on the ground. The results were far from perfect, but were promising—the drone recordings had a detection rate of roughly 60 percent what the on-site human observers could hear.

One of the biggest problems with the technique is that quadcopters themselves are loud, and noisy drones can frighten away animals. In actual field studies, researchers could use quieter flyers, or even balloon-hybrid drones.

What might the future hold for drones studying songbirds and other wildlife? Given higher quality detection devices, and possibly a signal analysis system, much like the military uses, to quickly identify individual species even in large groups, the data might be incorporated into a near real-time GIS system for up-to-date migratory analysis of a particular region or species. Ornithologists might then list drones among their favorite flying things.

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