Jan 21, 2025 Shades of Hitchcock’s Film “The Birds”
Video credit: Tamer ALKIS, iStock
In 1999, the West Nile Virus was introduced to the eastern United States through an unknown route. The virus was particularly lethal to crows and their relatives, such as blue jays. Experts estimated that the crow population in the U.S. declined by almost fifty percent due to the West Nile Virus outbreak. However, since then, crow populations have rebounded and are now estimated to exceed 30 million. Interestingly, crow populations have recovered more rapidly in urban and suburban areas, where predation by owls and hawks may be less intense.
The urbanization of American crows has led to increased complaints regarding their behavior. In Watertown, New York, the city has hired a company to reduce the local crow population due to noise and fecal contamination concerns. This company claims their efforts have decreased the crow population from 20,000 to approximately 5,000. In Washington State, several residents have reported harassment by crows, some of which appear to be cases of mistaken identity.
According to an article by WBI from a few years ago, crows can reliably recognize individual humans. They tend to greet warmly those who provide them with treats. However, if a person is perceived as a threat, the crows may respond by scolding them with harsh “caws” or even dive-bombing and landing on their heads. These aggressive behaviors can persist for years.
John Marzluff researched crow behavior at the University of Washington in Seattle, while Christian Blum, a cognitive scientist specializing in animal behavior at the University of Vienna, has also studied this subject. Both researchers utilized masks to investigate how crows and ravens react to perceived threats.
In Seattle, Marzluff wore an ogre mask while capturing seven crows on campus in a net in 2006. Afterward, Dr. Marzluff or a research assistant would periodically walk around campus wearing the ogre mask and record the number of crows that issued aggressive caws. As reported in the October 28, 2024, New York Times, the study found that the number of scolding crows peaked around seven years into the experiment and then gradually decreased until 2023, when all the crows ignored the person wearing the ogre mask.
Similarly, Christian Blum conducted a study in Vienna on ravens, another corvid species closely related to crows. He or a research assistant would walk through the campus wearing one of two masks. One mask was associated with carrying a dead raven, while the other had no threatening associations. Just as in Marzluff’s study, the ravens scolded the mask associated with the threat and ignored the non-threatening one.
If someone becomes the target of aggression from local crows, it can be challenging to change their negative attention. Dr. Blum noted, “If you really get under their skin [or feathers], they can hold a grudge for a very long time.”
Jill Bennett, a radio host in Vancouver, experienced unexplainable attacks from crows. To address this, she started carrying kibble and peanuts in her purse during her walks and began to feed the crows. A pair of crows started following her, and when a third crow dive-bombed her, her “hired” corvid companions defended her and chased away the intruder.
Ms. Bennett likens her crow feeding to a mafia-style shakedown; she views the snacks as protection money—the price she pays to avoid being attacked from above.
Regardless of what causes crows to harass people, I prevent our dog from chasing the crows while they pick up grain beneath the bird feeder during our neighborhood walks. It’s often cheaper and easier to prevent problems than to solve them later!