From the Wall Street Journal:
SYDNEY— Daniel Parfitt thought he’d found the perfect drone for a two-day mapping job in a remote patch of the Australian Outback. The roughly $80,000 machine had a wingspan of 7 feet and resembled a stealth bomber.
There was just one problem. His machine raised the hackles of one prominent local resident: a wedge-tailed eagle.
Swooping down from above, the eagle used its talons to punch a hole in the carbon fiber and Kevlar fuselage of Mr. Parfitt’s drone, which lost control and plummeted to the ground.
“I had 15 minutes to go on my last flight on my last day, and one of these wedge-tailed eagles just dive-bombed the drone and punched it out of the sky,” said Mr. Parfitt, who believed the drone was too big for a bird to damage. “It ended up being a pile of splinters.”
Weighing up to nine pounds with a wingspan that can approach eight feet, the wedge-tailed eagle is Australia’s largest bird of prey. Once vilified for killing sheep and targeted by bounty hunters, it is now legally protected. Though a subspecies is still endangered in Tasmania, it is again dominating the skies across much of the continent.
These highly territorial raptors, which eat kangaroos, have no interest in yielding their apex-predator status to the increasing number of drones flying around the bush. They’ve even been known to harass the occasional human in a hang glider.
Birds all over the world have attacked drones, but the wedge-tailed eagle is particularly eager to engage in dogfights, operators say. Some try to evade these avian enemies by sending their drones into loops or steep climbs, or just mashing the throttle to outrun them.
A long-term solution remains up in the air. Camouflage techniques, like putting fake eyes on the drones, don’t appear to be fully effective, and some pilots have even considered arming drones with pepper spray or noise devices to ward off eagles.
They are the “ultimate angry birds,” said James Rennie, who started a drone-mapping and inspection business in Melbourne called Australian UAV. He figures that 20% of drone flights in rural areas get attacked by the eagles. On one occasion, he was forced to evade nine birds all gunning for his machine.
The birds are considered bigger bullies than their more-docile relatives, such as the bald and golden eagles in the U.S. Wedge-tailed eagles are the undisputed alpha birds in parts of Australia’s interior but it’s not entirely clear why they’re so unusually aggressive towards drones. Scientists say they go after drones probably because they view them as potential prey or a new competitor.
“They’re really the kings of the air in Australia,” said Todd Katzner, a biologist and eagle expert at the U.S. Geological Survey in Boise, Idaho. “There’s nothing out there that can compete with them.”
The problem is growing more acute as Australia makes a push to become a hot spot for drones. One state, Queensland, recently hosted the “World of Drones Congress” and last year gave about $780,000 to Boeing Co. for drone testing. Amazon.com is expanding in Australia and could try using drones for deliveries, and the machines are increasingly favored by big landowners such as miners and cattle ranchers.
The eagles will often attack in male-female pairs, and they aren’t always deterred if their first foray fails. Sometimes they will come from behind, attack in tandem from above, or even stagger their assault. A drone operator may evade one diving eagle with an upward climb, but the second eagle can then snatch it, Mr. Rennie said.
“If you take your eye off that aircraft even for a couple of minutes, the likelihood is it will end up in pieces on the ground,” he said.
In late 2015, Andrew Chapman, a co-owner at Australian UAV, was mapping a quarry and landfill site near Melbourne, and figured it was close enough to the city that an eagle attack was unlikely. But when the drone was about half a mile away, an eagle “materialized out of thin air and knocked out the drone,” Mr. Chapman said. He spent two days looking for the machine, worth about $35,000 at today’s retail price, and had to ship it to the manufacturer in Switzerland for repairs.
More exotic defenses have been considered. Mr. Chapman said arming drones with pepper spray was discussed but quickly discarded, out of concern it could harm the birds.
“It’s a relief to be planning for jobs overseas because we know the wedgies aren’t there,” said Mr. Chapman, using the local nickname for the bird.
Rick Steven, a survey superintendent at the St. Ives gold mine in Western Australia, who uses drones to survey the pits, debated using something like a ShuRoo—a device mounted on cars that makes noise, which humans can’t hear, to keep kangaroos off the road. But he was concerned it would be cumbersome on the drone and may not ward off eagles anyway.
Instead, Mr. Steven and other drone operators make use of another weapon: time. The eagles are less active in the early morning, because the thermals—columns of rising air—they use to fly don’t develop until later in the day after the sun has warmed the ground.
In his first 2½ years flying drones at the mine, Mr. Steven said he lost 12 drones to eagle attacks, which cost his employer, South Africa-based Gold Fields Ltd. , some $210,000. During the past year, when he focused his flying in the morning, he has lost two—with two more close calls.
Any successes at deterring wedge-tailed eagle attacks in Australia could provide clues in how to minimize avian obstacles in other regions.
“Every time I go to a conference on birds and they’re having a workshop on drones, somebody tells me about this problem in Australia, about these wedge-tailed eagles,” said David Bird, a retired wildlife biology professor in Canada and founding editor of the Journal of Unmanned Vehicle Systems.
Mr. Parfitt, who began his drone business Aerial Image Works about three years ago, remains vigilant. Each of his last three jobs attracted an eagle attack.
Other birds will “fly at the drone and they’ll act in a very aggressive manner, but they don’t actually touch you,” he said. “I’m not scared of anything else attacking my drone except the wedge-tailed eagle.”
Write to Mike Cherney at email@example.com
Unfortunately no observations on hunting per se. However most time the eagles are sitting on trees and looking at water. Tons of photos of that. If the eagles have never seen the drone before and the drone is buzzing too close, they might move from one tree to another and watch the activity from a distance.
Good work Eugene. Enjoyed your paper.
Do you notice any difference in eagle behaviour if the drone is flying when / where the birds are foraging or is your work mostly focusing on nesting?
We fly with the eagles on regular basis.
If you know what are you doing, the birds ignore the drone.
To avoid birds just climb fast. They can't keep up with muscle power.
I find the worst to be nesting sparrows.
When I worked in NZ, I saw(heard) a farmer using sonic pulses to expel birds. They were audible to me, so not ultrasound, but very high pitched. Maybe investigating a ultrasonic sound generator that runs full time during flight. That should not be too heavy. I also find that the crack generated by the self defense tasers(the one that generates the spark) makes my pets scatter - not sure if that sound will carry in flight.
Have you experimented with different colors on the air frame. Would a brilliant neon pink be as attractive as white plane(that looks like a gull) or a yellow bird(that looks like a huge finch) or black that looks like a crow.
I have been buzzed by crows but not by large bird of pray.
Please keep us posted when you find a solution.
Even manned aviation is not safe from eagles! See here:
The report describes a golden eagle attacking a sail plane. The bird destroyed the canopy, was stuck half within the cockpit and the pilot had to throw him out of the cockpit with both hands!
In the following report 20 attacks against small manned aircraft (gliders, hanggliders, paraglider, helicopter and small aircraft) are documented and analyzed (English summary available):
Another challenge for the dev team....... eagle mode.
It is possible that not all birds survive an encounter with an UAV - see Simon Cherriman's thoughts here.
In my experience from flying normal RC planes, the trick is to gain altitude as quickly as possible. From a birds perspective if you are capable of flying higher then you are the predator. Doing sharp turns etc. only makes the bird more persistent, since this confirms to the bird that you are the prey.
Not very helpful during a way-point mission, but keep this in mind if you have to abort and take over manual control.
All the drones pictured are fixed-wing. They probably look like a competitor. Any rotory-wing craft attacks documented? I could see perhaps a multi-rotor attack, but what about a large heli? During the 15 years or so I flew larger helis (600 - 800 mm + blades) I never had a bird attack. Occasionally some would check out the heli, but back off when they got close. Since these machines could chop a few 1-2 cm tree branches and keep flying the birds probably knew to keep away.
If bird attacks are actually a problem maybe a heli might be a better choice - at least for some jobs. Of course if the wedge-tailed eagle has gone after large helis - probably with bad results for both - then other solutions are needed.