To Protect Livestock From Predators, Some Look to the Skies

In the summer of 2022, several researchers with USDA Wildlife Services held their breath as a drone pilot flew a large drone, equipped with a camera, toward a wolf standing in a pasture in southwestern Oregon. The team members, watching from a distance, expected the wolf to freeze or run away the minute the whirring rotors approached it. But to their disbelief, it did neither.

Instead, the wolf wagged its tail, stretched out its front legs, lowered its head, and lifted its butt — a classic canine invitation to play and precisely the opposite of the response researchers were hoping for. The project, led by Paul Wolf, the Southwest Oregon District supervisor for Wildlife Services, was designed to find ways to use drones to scare wolves away from livestock, not give the animals a new toy.

This story first appeared on High Country News and is republished here under a Creative Commons license..

Later that night, the researchers tried again, this time outfitting the drone with a speaker that broadcast human voices. This time, the wolf took off running. For the rest of the summer and fall, the field staff focused on using drones to discourage wolves from approaching cattle, in one case using a speaker-equipped drone to halt an ongoing attack. The three wolves fled, and the wounded steer survived. “We know for sure that we saved at least one [animal] doing this,” said Dustin Ranglack, the Predator Ecology and Behavior Project leader for Wildlife Services’ National Wildlife Research Center and a collaborator on the Oregon project. (An arm of the Department of Agriculture, Wildlife Services kills more than a million animals each year — predators like wolves, as well as invasive fish, birds and mammals — in addition to researching nonlethal livestock-protection measures.)

Ranglack and other researchers hope drones will help keep the peace between predators and livestock. “Early detection is your best means of mitigating conflict before something negative occurs,” said Jared Beaver, an assistant professor and wildlife management specialist at Montana State University. “Before livestock gets killed or before a wildlife species gets in trouble and has to be killed as well.”

Drones are already used for population surveys and even health assessments of hard-to-reach species, such as orcas. This can reduce the need for going up in small aircraft, one of the riskiest parts of a wildlife biologist’s job. 

But Beaver would like to see the technology more widely used with predators. He said that drones would likely be most effective when used with existing methods of predator deterrence, like range riders — people who accompany herds in order to deter wolves through their presence — guard dogs or strings of flapping flags, called fladry. If equipped with thermal sensors, cameras, and artificial-intelligence systems trained to recognize large predators, a drone could theoretically fly over a calving pasture at night and alert a sleeping rancher to possible trouble. Drones could also monitor areas where wolves or bears have been sighted, guiding range riders in their livestock-monitoring efforts.

Two wolves attack cattle. The drone successfully hazed the wolves out of the pasture (left). A wolf looks at the flying drone (right). The small circles are the heat signatures left by its paws, showing how it moved around while watching the aerial drone. Both images are from drone videos made during a night watch in southwest Oregon. Visual: USDA Wildlife Services

Ranglack’s analysis of the drones’ effects on wolves in Oregon showed that they can reduce attacks. Prior to the 2022 drone flights, a wolf killed a cow in the study area almost every other night. But when drones were used to detect wolves near cattle and then scare them away with recorded voices, wolves killed only two animals over 85 nights.

While wolves are only responsible for about 1 percent of cattle deaths in the Rocky Mountain states, predator attacks can be costly and emotional for ranchers. Some federal and state wildlife protections permit landowners to kill wolves that are caught in the act, but by heading off conflicts before they start, drones could reduce the use of lethal control.

Daniel Anderson, founding director of the nonprofit Common Ground Project, has been experimenting with drones on his family’s ranch in Montana’s Paradise Valley since 2017. Tucked inside Tom Miner Basin, the land is a haven for grizzlies and wolves. A licensed drone pilot, Anderson uses his drone to look out for his cows, surveying the landscape via his smartphone, which is connected to a handheld controller. If he detects a cow carcass, he can use his drone to check for nearby predators. “It’s a little dangerous to walk into those settings,” Anderson said. “Maybe we can use a drone to flush out animals, go in and do some recon to see if there’s a bear on that carcass.”

“Early detection is your best means of mitigating conflict before something negative occurs.”

After a neighbor was chased by a bear during a horseback ride, he asked Anderson to look for evidence of livestock predation by flying a drone into the densely wooded drainage where the incident occurred. Anderson’s drone saw no sign of cow carcasses, but discovered that the sow had two cubs, a possible explanation for her defensive behavior. “That’s obviously helpful,” Anderson said. “That’s a good use of the technology.” He’s also used a drone to monitor elk populations over the course of the year, and to watch how different animals — deer, moose, sandhill cranes — respond to drones. Anecdotally, he’s found they’re all sensitive to the disturbance, acting startled even when the drones are still hundreds of yards away.

In his office at Montana State University, Beaver is modeling the kind of simplified drone that he hopes to see become commercially available to landowners — a flying robot that can be operated without the help of computer scientists, software developers, or wildlife biologists. “I’m looking for those win-wins,” Beaver said. “From an ag standpoint, helping [ranchers] sleep better at night, and a win from a wildlife conservation standpoint, too.” He imagines a “Roomba for ranch operations” that could be activated with a smartphone.

But drones still face barriers to widespread implementation. “We’re all keenly aware of the limitations of this tool,” Ranglack said. For one thing, they’re expensive: Drones mounted with the thermal imaging capabilities necessary for nighttime monitoring and with speakers like the ones tested by Wildlife Services can cost $20,000 or more. Anderson purchased his own drone, a simpler model, for about half that.

Federal Aviation Administration regulations also require drone pilots to pass a certification test. And operators need to keep a line of sight on drones while they’re in use; the Oregon researchers were working in flat, open pastures where wolves could be easily spotted, but trees and rugged topography can obscure the view and make flight more challenging.

Then there’s battery life: A drone’s rechargeable batteries must be changed every half-hour or so. In at least one instance in Oregon, a drone that detected a wolf ran low on power and had to return to base before it could scare off the animal. While a ground crew was able to reach the site and stop the attack, the cow was injured so badly that it had to be euthanized. Anderson is also concerned that flying at high elevation, especially in the summer, can overheat drone batteries. “This isn’t something any producer can just decide, ‘Hey, I’m going to go do this and pick up and do it,’” Ranglack said. “At least not yet. But it has some real promise under the right conditions.”

For his part, Anderson worries about the effects on wildlife. “I don’t fly nearly as much now, just because of the impact,” he said. Flying a drone, he surmises, is akin to introducing another predator, and it could drive off or stress birds and other animals he’s not trying to keep away from his cattle. He also realizes that no single tool can fix everything. The number-one killers of his cattle aren’t wolves or bears but rather noxious weeds like larkspur, and, at least for now, Anderson can only find those by riding through pastures himself, on the back of a horse.

Kylie Mohr is a correspondent for High Country News writing from Montana.

This article first appeared on High Country News and is republished here under a Creative Commons license. It is a part of HCN’s Conservation Beyond Boundaries project, which is supported by the BAND Foundation.