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We've talked a great deal on this program about the use of U.S. drones overseas in places like Afghanistan, Yemen and Pakistan. But we're going to hear now about military drones flying over the U.S. and for some surprising reasons.
As Grace Hood of member station KUNC reports from Colorado, the U.S. Geological Survey is trying to find a second life for retired drones.
GRACE HOOD, BYLINE: When you think of drones, you don't necessarily think of bird watching, but that's what Geological Survey hydrologist Chris Holmquist-Johnson is demonstrating. He's standing on a gravel road surrounded by miles of sage brush southeast of Steamboat Springs.
CHRIS HOLMQUIST-JOHNSON: Prop clear.
HOOD: After one last check with his team, he launches a small four-pound Raven A drone into the wind.
(SOUNDBITE OF DRONE REVVING)
HOOD: Holmquist-Johnson explains that at this point, scientists are trying to figure out if they can capture thermal and photo images of the greater sage grouse using the drone. And what do the birds think?
HOLMQUIST-JOHNSON: So far, what we've seen is that they really don't seem to be bothered by it. We're able to get that imagery, and they don't flush or, you know, move on to a new location. So we're able to get images of them from the plane.
HOOD: The experiment is part of a larger project within the Department of Interior's Geological Survey to use retired military drones. In recent years, it's coordinated with state and federal agencies to use drones to study everything from mountain pine beetle damage in Colorado to documenting bank erosion along the Missouri River in South Dakota.
LEANNE HANSON: Are you going to put it into nav mode, Chris, and...
HOOD: Biologist Leanne Hanson cites one promising drone experiment, counting Sandhill cranes. In 2011, scientists compared results from Raven A flights to those of ground observers. They were accurate enough that in 2012 only the drone was used. In future years, Hanson says the practice could save federal agencies money.
HANSON: Our estimates are that it would be a tenth of the cost.
BRIAN RUTLEDGE: This is something that gives us eyes in the sky - no pun intended - to find places and creatures that we wouldn't have on record, otherwise.
HOOD: Brian Rutledge is executive director of Audubon Rockies. He's been watching the population of sage grouse decline for decades across the West. While he says he's in favor of any technology that might lead to a more accurate count of the species, he doesn't think any machine can entirely replace human ground observers.
RUTLEDGE: These will give us hints as to where we ought to look, help us understand populations better. They'll never replace somebody with a notebook and, you know, a pair of binoculars or a good spotting scope.
HOOD: Back at the test site, Geological Survey biologist Leanne Hanson watches as her colleagues guide the aircraft in with a remote control and no landing strip.
HANSON: And now, it's just gliding down and breaks apart. And again, it's designed to do that, to dissipate the energy.
HOOD: Here, researchers are also circumspect about how far this drone will advance bird counts.
HOLMQUIST-JOHNSON: Battery is out.
HOOD: Chris Holmquist-Johnson says one limitation comes from the lower resolution cameras in the Raven A. Overall, experiments with drone technology are in the very early stages.
HOLMQUIST-JOHNSON: As systems get better and sensors are better, then, you know, we'll be able to even do a better job of the science we're trying to answer.
HOOD: The Geological Survey office overseeing these drones gets more than a dozen calls a week from other Interior Department units interested in using them. Some upcoming experiments includes surveying pygmy rabbit habitat in Idaho and counting mule deer in Nevada.
For NPR News, I'm Grace Hood.