Bridget Ahern heard the drone coming, around 11 a.m. Saturday, while attempting to photograph Annie and Grinnell, UC Berkeley’s resident peregrine falcons, and soon afterward, “my heart sank,” she said.
As the drone approached the Campanile, where the pair has raised young since 2017, “I heard Annie vocalizing, and Annie flew out after it and came close to it,” Ahern said. “I thought she was going to try and attack it and was concerned she’d get injured. She made a couple passes at it and flew to the southeast.”
This isn’t the first time that drones have flown dangerously close to the falcons and their home. In the past few years, there have been at least 10 known drone flights near the Campanile, either caught on camera — there are three Cal Falcons webcams on the tower — or seen from the ground, said Sean Peterson, a Cal Falcons ornithologist. A few years ago, a drone even crashed and broke into pieces on the nest level of the tower’s south side.
Serious wounds and abandonment of a nest are a few of the dire consequences of encounters between birds and drones. Drones can only be flown on campus property if operators meet Berkeley’s strict requirements .
A drone crash last year at the Southern California nesting site of 3,000 elegant terns prompted worldwide headlines: The birds abandoned their 1,500 sand nests, which each held one or two eggs. Annie and Grinnell, who recently recovered from an attack by rival falcons , have just entered their sixth season of mating since arriving at Berkeley in late 2016; their eggs typically appear in March. Annie had been sitting in the pair’s nest box before the drone approached, said Ahern, who had been watching the raptor on her phone via one of the tower’s webcams.
“Falcons defending against a drone in their territory are likely to try to treat it like an invading bird competitor,” said Peterson. “They will dive on drones and attempt to drive them away. However, drones are not birds, so they won’t behave the same way, and it’s possible that a falcon can contact the drone’s rotors and get severely injured.”
Lynn Schofield, also a Cal Falcons ornithologist, added that while falcons are most aggressive toward drones when their young are readying to fly and are vulnerable, perched on the tower’s ledge, “they are most likely to simply abandon their home early in the breeding season when they don’t have babies yet.
“A falcon will rarely ever abandon a chick it already has because it has put a lot of time and energy into hatching and raising it. However, a bird might think twice about starting a family when it feels threatened.”
Ahern said she took a photo of the drone as soon as it appeared on Saturday, but then “put my camera down. I wanted to be able to see the interaction, in case Annie came in contact with the drone and got injured and needed to be located.” The photographer tried, but failed, to find the drone’s operator, then called campus police, who took down the details and sent an officer over.
“Our officer searched the area, but did not locate the drone’s pilot,” said Lt. Sabrina Reich, public information officer for Berkeley’s UCPD. “It can be very challenging to address unauthorized drone activity if we do not locate the pilot at the time of the incident.”
Members of the campus community operating drones in a “reckless, unsafe or irresponsible manner” or in violation of federal law, the UC’s unmanned aircraft system (drone) policy or Berkeley’s campus policy will be subject to disciplinary action under the appropriate code of conduct, personnel policies or collective bargaining agreement, according to Berkeley’s policy. Non-university drone users, it says, may be subject to UC police department enforcement, revocation of permission to fly over campus property and a ban on further flights over campus for up to five years.
Typically, said Mary Malec, a Cal Falcons raptor expert, “all of us on the ground have had to talk to drone operators once or twice, usually with good response. We think they’re not aware of the peregrines.”
Two years ago, when the falcons’ chicks were learning to fly, Annie took off after a drone while volunteers led by Malec were on the ground monitoring their fledglings’ attempts.
The drone operator, who took down his aircraft immediately after being approached that day, “ironically was a research biologist from South America and did not notice the peregrines, even when his drone was being attacked,” said Malec, “because he was looking at the control screen and not at the drone and Annie in the air.”
Ahern, who a few years ago became a frequent visitor to campus to photograph the falcons — “I heard the screeching of the fledglings. I was hooked,” she said — approaches drone operators, too, and reminds them that they need the campus’s permission.
“I also stress that they’re wildlife, these falcons, and that Annie and Grinnell are famous. You don’t want them to be injured,” she said. “Most of the time people say, ‘Oh, OK,’ and have complied. One time, someone was nice enough about it, but kept flying his drone, so I called the police.”
Ahern said Berkeley’s falcons have been her “spark birds,” a term for birds that help spark people’s interest in birds and in birding. “I’ve definitely grown very attached to Annie and Grinnell. I love going onto the campus and hoping to get photos of them,” she said. “I don’t want anything to happen to them.”
Peterson said his message to drone operators is this: “Find a different place to fly. … the threat to Annie and Grinnell is real. They could be severely injured or die from striking a drone rotor,” and if they abandon their territory, it would be “a huge loss.”