Over and over, the crows attacked Lisa Joyce as she ran screaming down a Vancouver street.

They divebombed, landing on her head and taking off again eight times by Joyce’s count. With hundreds of people gathered outdoors to watch fireworks that July evening, Joyce wondered why she had been singled out.

“I’m not a fraidy cat, I’m not generally nervous of wildlife,” said Joyce, whose crow encounters grew so frequent this summer that she changed her commute to work to avoid the birds.

“But it was so relentless,” she said, “and quite terrifying.”

Joyce is far from alone in fearing the wrath of the crow. CrowTrax, a website started eight years ago by Jim O’Leary, a Vancouver resident, has since received more than 8,000 reports of crow attacks in the leafy city, where crows are relatively abundant. Such encounters stretch well beyond the Pacific Northwest.

A Los Angeles resident, Neil Dave, described crows attacking his house, slamming their beaks against his glass door to the point where he was afraid it would shatter. Jim Ru, an artist in Brunswick, Maine, said crows destroyed the wiper blades of dozens of cars in the parking lot of his senior living apartment complex. Nothing seemed to dissuade them.

Renowned for their intelligence, crows can mimic human speech, use tools and gather for what seem to be funeral rites when a member of their murder, as groups of crows are known, dies or is killed. They can identify and remember faces, even among large crowds.

They also tenaciously hold grudges. When a murder of crows singles out a person as dangerous, its wrath can be alarming, and can be passed along beyond an individual crow’s life span of up to a dozen or so years, creating multigenerational grudges.

Attacks by aggrieved crows can become the stuff of horror films, with lives being seemingly transformed into the Hitchcockian nightmare of The Birds.

Gene Carter, a computer specialist in Seattle, was followed by crows that lurked outside his windows for the better part of a year.

“The crows would stare at me in the kitchen,” he said in an interview. “If I got up and moved around the house, they would find any place where they could perch and scream at me. If I walked out to my car they would divebomb me. They would get within an inch of my head.”

Carter knows precisely what set off the attacks. One day in his backyard, he saw crows encroaching on a robin’s nest and launched a rake into the air.

But he never imagined that the crows’ revenge would last so long. The mob learned to identify the bus he took on his way home from work, Carter said. “They were waiting for me at the bus stop every single day,” he said. “My house was three or four blocks away and they would divebomb me all the way home.”

The harassment stopped only when Carter moved.

Experts say the majority of crow attacks occur in the spring and early summer, when protective parents are watching over their young and defending their nests from possible encroachers. But in other cases, the reason for an attack is not so clear.

When crows stalked her in July, Joyce noticed on a local Facebook group that several other women in her neighbourhood were also being divebombed — and that they all had long blond hair.

“I wondered if there was a connection.” Joyce said. “Do they have a beef with a fair-haired person?”

On a slate-grey Sunday morning last month, a man in an ogre mask trudged across the campus of the University of Washington in Seattle. He passed prospective students and their parents, who paused their tour of the school to gawk at this person stalking the grounds looking like an actor in a low-budget Halloween thriller.

The character in the mask was John Marzluff, a professor who has spent his career studying human-crow interaction. Dr Marzluff has developed a high regard for the birds’ intelligence. He describes crows as “flying monkeys”, because of their aptitude as well as their large brains relative to their size.

How long do crows hold a grudge? Marzluff believes he has now answered the question: around 17 years.

His estimate is based on an experiment that he began in 2006 on the Washington campus. Marzluff captured seven crows with a net while wearing that ogre mask. The birds were soon set free, but, Marzluff says, the episode traumatised the crows and other members of the murder that witnessed it.

To test how long the campus’s birds would hold onto their grudge, Marzluff or his research assistants would put on the ogre mask periodically and walk around campus, recording how many crows let out aggressive caws, a sound that experts call scolding. The number of scolding crows crescendoed around seven years into the experiment, when around half the crows he encountered cawed vociferously.

Over the next decade, according to data Marzluff has collected but not yet published, the numbers of grudge-holding crows gradually tapered off.

During his September walk, Marzluff recorded in his notebook that he had encountered 16 crows. And for the first time since the experiment began, they all ignored him.

Christian Blum, a cognitive scientist specialising in animal behaviour at the University of Vienna, conducted a similar multiyear experiment partly inspired by Marzluff’s work, using ravens, which are cousins to crows in the corvid family. “They are also excellent grudge holders,” Dr Blum said of ravens.

In the study, which ran from 2011 to 2015, Blum and his colleagues wore a mask and carried a dead raven past an aviary filled with live ravens. They then donned a different mask, a control, and walked without the dead raven.

Just as in Marzluff’s experiment, the ravens scolded the “dangerous” mask — even without any dead raven present — with much higher frequency than they did the control. And the scolding lasted for the duration of the experiment, suggesting that ravens’ grudges were also very long-lasting. “If you really get under their skin they can hold a grudge for a very long time,” Blum said.

Marzluff’s experiment on the Washington campus also had a control mask, and the way the crows interacted with it — scolding the wrong mask — might offer hints as to what happened to the fair-haired Joyce and other blond women in Vancouver.

Lynne Peeples, a science writer in Seattle, wondered if a crow attack during a jog years ago was a case of mistaken identity. Marzluff’s control was a mask of Dick Cheney, the former Vice-President. Although it was scolded far fewer times than the ogre mask, there were still a small number of crows that cawed at it, which he interpreted as a potential susceptibility to mistaken identity.

This resonates for Lynne Peeples, a blond-haired science writer in Seattle. Around a decade ago, she was jogging around a lake near her home when a crow divebombed her. She felt a sharp peck on the top of her head.

As she continued her run, she saw a man with a long blond ponytail running after and kicking ducks and other birds at the water’s edge. The man seemed to be suffering a mental health episode and Peeples wondered if the crow that attacked her had mistaken her for him.

Mistaken identity or not, the crow attacks persisted. On the same day she was pecked near the lake, Peeples was dining outside in the courtyard of her apartment. Crows took turns swooping down on her, narrowly missing her head and forcing her to move inside.

Similar attacks followed. “For the next couple years, every time I saw a crow I was scared I would be attacked,” Peeples said.

Bribe and tax

Faced with the terrifying prospect of being stalked for very long periods of time, victims of corvid attacks struggle with the right way to respond.

Back in Vancouver, there is little that crow victims can do. Angela Crampton, an environmental specialist with the municipal government, says the city is proud of its thriving bird population, which includes crows, partly because it is a measure of the city’s ecology.

“There’s a sub-culture of crow appreciation here,” she said. Crampton says the city’s main message is of “coexistence” and that the authorities do not remove crow nests or trim trees with the goal of reducing attacks.

Others who have been harassed by crows in Vancouver have come to an accommodation with the birds. Often it’s in the form of what they describe as a bribe.

A decade ago, Jill Bennett, a radio host in Vancouver, was relentlessly attacked by crows as she was walking her dog. She escaped by ducking into a parking garage.

“I had never done anything mean or violent towards the crows,” Bennett said.

When it happened again, Bennett began keeping kibble and peanuts in her purse, dispensing the snacks as she took her walks.

A pair of crows took to following her, a sort of protective entourage. When a third crow with distinctive feathering divebombed Bennett, the entourage went on the offensive, chasing away the interloping crow.

Bennett compares her crow feeding to a mafia-style shakedown. It’s protection money, she says, the price of knowing you will not be attacked from the sky.

“I call it the crow tax,” she said.

New York Times News Service