Vancouverites can expect, each spring, the onset of warmer weather to bring with it a strange warning along with blooming trees and increasing sunlight – crows swoop down on unsuspecting pedestrians in the city.
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In fact, such is the frequency of the occurrence that a crowdsourced online map exists that marks out areas of crow “attacks” for the benefit of those walking about to avoid any danger. While the whole thing might seem like a hoax, the birds are likely following their natural instinct.
Why do crows in Vancouver attack humans?
Such behaviour is often seen towards the end of spring when the American crow starts its breeding period. The Wildlife Rescue Association of British Columbia says that adult crows are extremely protective of their chicks once they hatch, especially during the period when the youngsters have left the nests but are still unable to fly well.
At this stage, young crows often spend days on the ground learning to fly. If a human inadvertently gets too close, the parents of the crows will normally make an aggressive dive towards them or flap their wings at the humans to try and drive them away from the perceived danger.
These encounters are more defensive than aggressive.
Residents came up with a map to pinpoint crow attacks
Instead of being surprised every time, residents of Vancouver now have a tool that helps them avoid attacks.
The online resource called CrowTrax allows users to share their experience of crow attacks in certain places. They can also rate the intensity of the experience, providing a real-time map of the city's seasonal hotspots of crows.
CrowTrax was founded in 2016 by Jim O'Leary and Rick Davidson, instructors from Langara College, who intended to show how geographic information systems can help solve everyday issues. The idea proved popular, attracting more than a few hundred public contributions and continuing to receive reports each nesting season.
As reported by CityNews Vancouver, there are more than a thousand user reports annually submitted through this crowdsourced map.
The birds can remember human faces
One reason many people find these encounters unsettling is that crows appear to recognise individuals.
That ability has been supported by scientific research. A landmark study published in the journal Proceedings of the National Academy of Sciences (PNAS), available through PubMed , found that wild American crows can recognise human faces associated with threatening experiences and may remember them for years. Researchers also observed that the birds communicate this information to other crows, allowing future generations to identify potential threats.
This may help explain why some Vancouver residents report being repeatedly targeted after a single unpleasant encounter with a crow.
The birds have the ability to remember human faces
The first cause of fear among humans is that the crows can recognise people. Studies suggest that crows can recognize human faces.
According to a 2010 study published in the journal Animal Behaviour, available through ScienceDirect , American crows can recognise human faces associated with threatening experiences and remember them for years.
The researchers exposed wild crows at five sites near Seattle to a novel “dangerous” mask while trapping, banding and releasing 7–15 birds per site, then compared their reactions with neutral masks in fully crossed trials. They found the birds scolded the dangerous mask far more than neutral ones, even when worn by different people, and the response persisted for at least 2.7 years.
This is why some people from Vancouver have the feeling of being targeted by a crow even once threatened.
What is the course of action that you can take when a crow flies at you?
Instead of trying to frighten the bird away, wildlife rescue experts suggest staying still.
In the words of the Wildlife Rescue Association of British Columbia, one simple way out is just to go away from the place. Having an umbrella is recommended as a form of protection while walking through known crow nesting areas, and a hat may help prevent contact with the bird.
Feeding crows is not a good idea; regular feeding can lead to more trouble. If you find a baby crow on the ground, leave it alone unless it is injured, since fledglings often stay outside the nest for several days.
An unusual tradition of spring in Vancouver
Although these encounters happen each year, many Vancouver residents still feel fond of the birds.
When scientists were investigating public attitude toward the crows in Vancouver, they noticed that despite some occasional attacks, people still perceive the birds positively. Their intelligence, sociability, and role in urban ecosystems may help explain their popularity in Vancouver.
One of the biggest crow roosts in North America is located in Vancouver. In autumn and winter, thousands of crows come together around the Still Creek area in Burnaby each evening and then separate in the morning. The roost is a familiar sight for many Vancouver residents.
To visitors, checking a crow-attack map before a walk may seem unusual. But for Vancouver residents, it is a sign that spring has arrived.
