Scientists have techniques for tracking megafauna—wolves, say, or moose. They catch ’em, sedate ’em, slap on a special collar, and wait for the data from GPS satellites to flow in. But what about birds? Or dragonflies? Tracking devices big enough to ping satellites are too bulky for such wee creatures. They’re expensive too. United Air- lines will soon swoop to the rescue, mounting radio receiver antennas on its planes to pick up signals from smaller, cheaper animal tags.

“The idea is to create a new, low-altitude network,” says Peter Marra of the Smithsonian Conservation Biology Institute. His project, Partners in the Sky, is working to get the tags— which rely on trusty VHF radio technology—down to a weight of just 0.15 gram. Then some of United’s 5,300 daily flights will help gather massive amounts of data as they cruise the lower atmosphere, tracking previously untrackable vanishing species like the American Wood Thrush or monarch butterfly. “The first step in stopping a decline is to figure out when and where animals are dying,” Marra says. “I can’t mitigate it if I can’t identify it.”

The program benefits bigger critters too: The low cost makes it possible to tag more animals. Plus, it’s convenient. In the old days, researchers had to make dedicated flights and trips into the wild with receivers to see what pings they could pick up. But the airplane network will mean “I can sit at my computer drinking beer,” Marra says. The receiver’s design is still in process, but United is on board, tray tables up, ready for takeoff.