Hazing Wolves with a Drone
USDA Wildlife Services demonstrates the effectiveness of drones to haze wolves, providing a new tool to deter predator attacks on livestock.
Federal animal damage control specialists on night watch over a cattle herd experiencing repeated wolf attacks waited for wolves to appear in the dark, and then set out a high-tech drone to run the wolves away from the cattle. It was a successful experiment that agency officials will continue to investigate and refine, adding another tool to the toolbox of non-lethal deterrence measures for predators.1
When state and federal officials in Oregon requested USDA Wildlife Services join them in “night watch” activities to prevent wolf depredation on a cattle herd in the Klamath Basin, Wildlife Services agreed to assist.
Wolves in this portion of western Oregon remain under federal protection. Between July 12 to August 1, 2022, the Rogue wolf pack had 11 confirmed depredations on cattle, but lethal control of these wolves was not an option for wolf managers.
Each evening, wildlife agency personnel would push the cattle a few hundred yards away from a fence lined by trees and out into the open pasture. Using thermal optics, agency personnel would wait and watch for wolves to cross from the trees toward the cattle before taking action to haze the wolves away. While the effort was relatively effective, it was limited by the amount of area an individual could scan with the thermal imaging device from the ground.
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Testing a drone to haze wolves
To increase the effectiveness of the night watch, Wildlife Services sought and received permission from the U.S. Fish & Wildlife Service to use a drone equipped with a thermal imaging camera to monitor and haze wolves in the Klamath Basin, according to a paper just published in the journal Global Ecology and Conservation.
In the first encounter with the drone, a wolf watched with interest as the drone approached, prompting the wolf to play bow in response. Instead of being afraid of the drone, the wolf interacted with it in a playful manner. The drone was equipped with lights, but no speaker, so the rotor noise wasn’t enough to scare the wolf.
That prompted the drone operator to attach a speaker to the drone and return to the wolf as it began to approach the cattle. The wolf once again demonstrates toward the drone, but when the pilot yells at the wolf through the speaker, the wolf turns and runs away from the drone as it hazes the wolf out of the pasture. {These video clips do not include audio recordings.}
Throughout the course of this experiment, the drone operator used lights or sound (music, recorded gunshots, or the drone pilot’s voice) to haze the wolves whenever they were detected approaching cattle, but found that the human voice was most effective at deterring wolves from the cattle.
Stopping an Active Attack
The effectiveness of the drone was demonstrated in this video in which three wolves are seen actively attacking a steer. One wolf turns and runs from the drone, but the other two wolves continue attacking the steer. When the drone pilot yells at the wolves through the speaker, the wolves immediately stop their attack and run away. The paper reports that the steer survived the attack and only needed minor medical attention the next morning.
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Limitations
The battery life of the drones is limited, with about 22 minutes of flight time before needing to be recharged. One of the videos uploaded with the paper demonstrates the significance of this shortcoming by showing a wolf attacking a cow as the drone approaches. As the drone moves closer to the wolf to begin hazing, it suddenly aborts the mission to return to its home base for a recharge, an automated response to a low battery. Although the drone operator had already summoned the ground crew to help chase the wolf away, the cow had to be euthanized due to severe injuries.
The researchers note that advances in battery and drone technology should help to increase flight times, as well as the ability to change batteries without powering down the drone. Other limitations involve topography and land cover. In thick vegetation, the drone pilot may be unable to maneuver close enough to a wolf for hazing, or obstructions may pose a risk of crashing the drone (as demonstrated in one of the project’s videos). The drone must remain within the line of sight of the drone operator, which also poses limitations. Although prices are expected to decline as drone use becomes more widespread, these equipped drones range in cost from $10,000 to $20,000 each, posing an economic feasibility limitation to broad application.
Future research
Wildlife Services plans to continue investigating the effectiveness of drones as a non-lethal tool to deter predators. I checked in with Wildlife Services National Wildlife Research Center Utah Field Station Leader Dustin Ringlack and learned that the research will expand to answer questions about the effectiveness and limitations of drone use.
In addition to exploring the amount of effort needed for drones to be effective (man hours, flight hours, spatial patterns), researchers will conduct a large trial in different canopy covers to gauge at what level canopy cover becomes limiting for a drone to detect wolf-like animals.
They will also continue to document the behavioral reactions of wolves and other wildlife to the drone, providing insights to wildlife managers, livestock producers, and the general public. Although wolves eventually habituate to most non-lethal tools, the adaptive movement of a drone may help to prevent wolves from habituating, offering promise for continued application of drones to keep livestock safe from attacking predators – a new tool in the toolbox.
“We hope that future work can lead to the development of an artificial intelligence enabled drone that can monitor cattle and send an alert to the producer or appropriate agency when wolves or other predators are detected.”
The paper, “Drones as a potential hazing tool to prevent wolf depredations on livestock,” was co-authored by Dustin Ranglack, Loredana McCurdy, Paul Wolf, and Luke Miller. Click here to watch more videos of the drone in action, including hazing wolves, coyotes, and a black bear. The paper provides a narrative of what’s happening in each video.
The image and videos in this Range Writing newsletter are used pursuant to a Creative Commons license (https://creativecommons.org/licenses/by-nc/4.0/) that were created in association with this project and published paper: Dustin H. Ranglack, Loredana M. McCurdy, Paul C. Wolf, Luke Miller, Drones as a potential hazing tool to prevent wolf depredations on livestock, Global Ecology and Conservation, Volume 56, 2024, e03333, ISSN 2351-9894, https://doi.org/10.1016/j.gecco.2024.e03333.