Iraq resents American drones that monitor outside the U.S. embassy in Baghdad. Iran is delighted to capture a high-tech U.S. drone. And the United States plans more drone purchases even amid slowing growth of the military budget.
As remote-control airplanes get cheaper and better, drones seem to be everywhere:
Law enforcement: Drones are searching for drug traffickers in the Amazon and for illegal immigrants along the U.S.-Mexican border. Tampa, Fla., wants drones to watch protests at the Republican National Convention.
Environment: Remote-control airplanes have photographed eroding banks on the Missouri River.
Archeology: The Los Angeles Times reported that “Archaeologists in Russia are using small drones and their infrared cameras to construct a 3-D model of ancient burial mounds.”
Going into harm’s way: In Japan, drones have sprayed pesticides on farms and monitored the melted-down Fukushima nuclear plant. In Costa Rica, an unpiloted airplane is sampling air to predict a volcanic eruption.
And it turns out that drones are ideal for watching wildlife: rabbits, sea lions, gulls and a range of elusive or inaccessible species.
Counting the mini-bunnies
Researchers in Idaho have used drones to track the pygmy rabbit, a hand-size mammal that eats sagebrush. The rabbit, a “species of concern” in Idaho, is already extinct in neighboring Washington State.
Pygmy rabbits are reclusive, spending much of their time inside burrows, says Jennifer Forbey, an assistant professor of biology at Boise State University. Forbey, along with Janet Rachlow at the University of Idaho, the U.S. Geological Survey, and Washington State University, is using used military drones called Ravens to explore how habitat factors like cover, forage quality and temperature affect rabbit populations.
The Ravens are small, and able to carry only one of these instruments at a time:
an Infrared sensor to measure habitat temperature.
A sensor for a wavelength of light associated with nitrogen, a key indicator of plant health. Since sagebrush provides dinner and concealment, finding healthy sagebrush can help to identify good habitat for the rare rabbit.
The drone can cover the entire two-kilometer square site in about three hours, but its gadgetry sees neither rabbits nor their burrows. Because the drone noise would scare the rabbits back into their burrows, the plane does not work when the bunnies are likely to be active.
To find the animals, Forbey says, “We have to walk for days and days, to identify where the rabbits are. We hike around, looking for fresh fecal pellets, fresh digging, fresh clipping on plants.”
But the data on forage quality, combined with tried-and true shoe-leather counting, shows that the rabbits are discriminating eaters. “They are specialized to sagebrush, but not all [sagebrush] plants are created equal, some types are more palatable, and also provide better cover for them,” Forbey says.
It’s possible that in winter drones could get a better picture of rabbit activity by looking for tracks in the snow.
To actually see rabbits from the air without frightening them, Forbey suggests a back-to-the-future approach — perhaps lighter than air craft.
“We are trying to develop some other platforms, maybe blimps, that could stay static over burrows to get infra-red video of rabbits without making noise.”
Although airborne surveys have begun, they are a help but not a panacea, says Forbey. “Not much is known about pygmy rabbits. They are cryptic. You have to spend the time walking the habitat.”
Gulls in Spain
Black-headed gulls nest in large colonies, and like many colonial birds, monitoring from the ground is difficult, and viewing from conventional aircraft can be expensive and confusing.
Pick up a battery-powered, radio-controlled model airplane, and the picture changes, says Francesc Sarda, at the Center for Forestry Technology of Catalunya, in Spain. When the drone flies over at an altitude of 30 to 40 meters, “The gulls hear it, but they don’t identify it as predator, don’t know what kind of element it is, and so they do not care about it.”
In a 2010 study,1 Sarda equipped the plane with a still camera, pointing straight down. A video camera in the “cockpit” broadcast a live feed to a laptop on the ground, where the “pilot” operated controls.
The plane is “easy to fly, many people do it for hobby,” says Sarda, and it’s affordable — at just 1,400 Euros for the plane and the equipment. Depending on wind, the plane can stay aloft for 15 to 20 minutes, but batteries are cheap, and easily replaced before the next flight.
Water birds often nest in dense colonies, and can be difficult to study. Those that nest on cliffs can be observed from the side. On flat land, wildlife biologists may have to walk through the colony, but “If there are thousands of birds, it’s very difficult to count,” Sarda says.
Encounters with human counters can also annoy the birds, he adds. “In our case, they will fly away, even if there are chicks or eggs on the nest. You have to be very careful.”
The drone sidesteps this problem, he says. “You can do your count, and repeat your sampling” after a week or a month, to assess changes.
Laws about low-level flight are much less stringent in Spain than in the United States, Sarda says, and the system is “very cheap, compared with manned aircraft. You can use it yourself, whenever you want.”
See the sea lion
Sea lions and the fishing industry are squaring off in the Gulf of Alaska, where a rapid population decline of Stellar sea lions has been blamed on a scarcity of the fish they eat. But studying these fearsome and elusive creatures is difficult and data are sketchy, says Greg Walker, who manages the unmanned aircraft program at the University of Alaska. “The sea lion is an endangered species, and it’s affecting the fishery, but the science behind it is pretty spotty. The sea lions that have been monitored are healthy, not starving.”
Fishing restrictions are costly to the industry, and Walker observes that boats are catching more fish in the same amount of time, which suggests no scarcity of prey. “Their technology is no better than it was five years ago, and if they are catching more fish, maybe there are more fish” in the Gulf, he says.
Currently, sea lions are counted by looking at “haulouts,” rocky locations along the shore where these mammals mate and give birth, but the Aleutian Islands are hardly an ideal place to fly, Walker says. Airports can be hundreds of miles apart, and weather predictions cannot accurately say if clouds will block the view, wasting time and money.
Last June, Walker and his colleagues launched a drone from a fishing boat standing offshore. After a 12-mile flight, the drone flew over the colony, without causing obvious disturbance, and obtained video and photos clearly showing the sea lions.
Ironically, the same restrictions on fishing that were enacted to protect the sea lion have made fishing boats scarce. “We started working with a fishing cooperative; would fly off their boat while they were fishing, since they were going to be in the area anyway,” says Walker. “But closing the fishery has meant fewer fishing boats in the area,” and the lack of convenient launch pads could raise the price of drone-based monitoring.
If cost can be contained, larger surveys are possible, Walker says. “We will try to survey more of the island coastline, not just the historic haulouts. We want to know, is this a real population decline, or are they just in another part of the habitat? If you are always looking at the same street address, when someone moves down the street,” you may think they are dead, he notes. “Maybe a more consistent survey would find more of the sea lions.”
Eventually, if he can round up a bigger drone, Walker would like to use synthetic aperture radar, which can see through clouds, and could sidestep, finally, the cloud problem. But he also hopes the drones can fly at 500 feet, beneath many clouds. Flying that low is dangerous for manned aircraft, but that concern does not apply to disposable drones.
Having proved the concept of drone-powered surveillance of the sea lions, Walker and associates are planning to begin a three-week campaign in March.
Stop us from droning on!
Drones have a broad range of advantages compared to other ways of studying the environment. We’ve already mentioned how they can get access to awkward locations without bugging the animals.
Flying low and slow, drones can also identify and measure invasive weeds or many other types of ecological dislocation.
H. Franklin Percival, program leader for unmanned airplane research at the University of Florida, says safety is a critical motivation for using drones. “Low-level manned aircraft is the leading cause of workplace mortality for wildlife biologists. Wildlife biologists do this kind of thing all the time, studying salmon nesting, alligators in Florida, seals in Alaska, there’s a lot of low-level stuff.”
In 2010, a pilot and two biologists died in a helicopter crash while studying salmon nesting on the Selway River in Idaho. “That drives the interest [in drones] now,” says Percival. Before nesting, salmon fan away sand and gravel on the river bottom, “and we can see these from the air.”
In the United States, a major limitation on scientific use of drones comes from the Federal Aviation Administration, which is, rightly, worried about collisions between piloted planes and drones. Currently, the FAA requires that the pilot or a spotter be a licensed pilot, and limits a drone’s range and altitude to avoid danger. Those restrictions raise both the cost and bureaucratic rigmarole, and ecologists and the unmanned airplane industry are hoping for a change.
On Feb. 6, the Senate sent legislation to the President requiring FAA action on the issue within three years, USA Today reports.
If the concern is safety, new, more relaxed standards seem most appropriate to drones that fly short distances at low altitude.
If the FAA redrafts regulations to maintain safety while allowing more civilian use of drones, Forbey of Boise State expects ecologists to be lining up for unmanned aircraft. “This integration of technology with ecology and conservation is really exciting. I think what these planes provide is a spatial level that you can’t get from satellite, and can’t get from being on the ground. Both in terms of the area they can cover, and the type of data they offer, they fill a gap.”
Let a thousand drones bloom
Robot planes and the associated technology of cameras, communications and GPS-based recording of location are moving ahead even as the FAA promulgates regulations. At the University of Florida, Percival, who has directed the development of five generations of a robot plane called Nova, says drones should be designed according to the scientific goal. “What are the data required? Can it deliver that kind of data, and can you do the appropriate statistics to give reliable information? The airplane should be built around your question.”
As drones with ever more sophisticated sensors return a growing quantity of data, Percival favors automating data-processing to spit out reliable data that can be manipulated statistically. “To estimate the number of nesting birds in a pelican colony, we want to differentiate the components in the imagery with a computer as opposed to some guy’s eyeballs.”
Photos show a lot, but they do not automatically reflect reality, Percival says. “Just because we can see well does not mean the numbers are as precise, as accurate, as we’d like.”
— David J. Tenenbaum
- Fine-scale bird monitoring from light unmanned aircraft systems, Francesc Sarda-Palomera et al, Ibis (2012), 154, 177–183 ↩
- Storm chasing drones ↩
- Drones as law enforcers ↩
- Monitoring marine wildlife ↩
- Watch an UAV take off ↩
- Amazing aerial footage, from a golf course to Cameroon ↩
- FAA laws surrounding civilian UAV use can get sticky, but may be changing soon ↩
- Drone DIY ↩
Tags: airplane, bird ornithology, drone, environmental research, Federal Aircraft Administration FAA, Florida, Francesc Sarda, Greg Walker, gull, H. Franklin Percival, invasive exotic species, Jennifer Forbey, pygmy rabbit, radio, sea lion