The U.S. military and law enforcement agencies have seen increased public scrutiny on the domestic use of the robotically piloted planes known as drones. Working on the sidelines of this debate, the U.S. Geological Survey has been trying to find a second life for retired military drones in the areas of environmental and wildlife management. Instead of watching the battlefield, these drones are watching birds.
Earlier this month, scientists spent three days flying a small 4-pound Raven A drone above the breeding grounds of the greater sage grouse, about 120 miles northwest of Denver. USGS hydrologist Chris Holmquist-Johnson says researchers are trying to figure out if they can use the drone to capture photo and thermal images of the birds without disturbing them.
"So far what we've seen is that they really don't seem to be bothered by it," Homquist-Johnson says. "We're able to get that imagery and they don't flush or move on to a new location."
The experiment is part of a larger project. In recent years, the National Unmanned Aircraft Systems Project Office has 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.
The USGS also has had previous success with birds, counting Sandhill Cranes in Monte Vista National Wildlife Refuge in southern Colorado. USGS biologist Leanne Hanson says that in 2011, scientists compared counts from the results of Raven A flights to those of ground observers and found the flight data accurate enough to switch to using drones exclusively in 2012.
In future years, the practice could save federal agencies money, Hanson says. "Our estimates are that it would be a 10th of the cost."
Brian Rutledge, executive director of Audubon Rockies, has been watching the population of sage grouse decline for decades across the West. And 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 observers on the ground.
"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," he says. "These will give us hints as to where we ought to look, [and] help us understand populations better. They'll never replace somebody with a notebook and a pair of binoculars or a good spotting scope."
Researchers are circumspect about how much they think the remote planes will advance bird counts. Holmquist-Johnson says one limitation comes from the lower resolution cameras and sensors in the Raven A. Overall, experiments with drone technology are still in the very early stages, he says.
"As systems get better and sensors are better, then we'll be able to do an even better job of the science," he says.
The USGS office overseeing these robotic planes gets more than a dozen calls a week from other Interior Department units interested in using them. Upcoming experiments include a climate change study near Niwot, Colo., efforts to count mule deer in Nevada, and a survey of pygmy rabbit habitat in Idaho.