Before you battle a crow again, think twice. These birds may be found practically anywhere, and their cawing can create quite a fuss. But did you know that they can remember human perpetrators’ faces for years?
Crows don’t forget a face — and they hold grudges, too.
Crows, as well as their relatives such as ravens, magpies, and jays, are known for their intellect and ability to thrive in human-dominated environments. It’s possible that this ability has something to do with interspecies social abilities. Researchers have shown that crows in the Seattle area, where fast suburban construction has attracted a healthy crow population, can recognize individual human faces.
For more than 20 years, John M. Marzluff, a wildlife biologist at the University of Washington, has studied crows and ravens and has pondered if the birds could recognize particular researchers. Previously trapped birds appeared to be afraid of specific scientists and were often more difficult to catch.
“I thought, ‘Well, it’s an annoyance, but it’s not really hampering our work,’ ” Dr. Marzluff said. “But then I thought we should test it directly.”
Dr. Marzluff and two students wore rubber masks to test the birds’ recognition of faces separately from clothes, gait, and other individual human features. A caveman mask was labeled “dangerous,” while a Dick Cheney mask was labeled “neutral” in a show of civic kindness. Seven crows were then trapped and banded on the university’s Seattle campus by researchers wearing the deadly mask.
The researchers and volunteers wore the masks on campus in the months that followed, this time walking prescribed paths and avoiding annoying birds.
The crows had remembered. Even when the threatening mask was concealed with a hat or worn upside down, they reprimanded persons wearing it substantially more than they did before they were confined. The neutral mask elicited very little response. Over the last two years, the effect has not only lasted but has multiplied. Dr. Marzluff said he was reprimanded by 47 of the 53 crows he encountered while wearing the deadly mask on a recent tour through campus, far more than had experienced or witnessed the first capture. Crows, according to the researchers, learn to detect harmful humans from both their parents and other members of their flock.
One volunteer, Bill Pochmerski, a retired telephone company manager who lives near Snohomish, Washington, described one of the deadly masks as “quite spectacular, “The birds were really raucous, screaming persistently,” he explained, “and it was clear they weren’t upset about something in general. They were upset with me.”
Crows were substantially more inclined to scold observers wearing a dangerous mask, and when confronted with observers wearing both dangerous and neutral masks, the birds nearly always chose the dangerous face to harass. Angry birds nearly touched their human foes in downtown Seattle, where most passersby ignore crows. Crows conveyed their displeasure from afar in rural areas, where they are more likely to be considered noisy “flying rats” and shot.
Despite the fact that Dr. Marzluff’s research is the first systematic investigation of human face recognition in wild birds, his preliminary findings back up the concerns of many other researchers who have seen similar abilities in crows, ravens, gulls, and other species. Konrad Lorenz, a pioneering animal behaviorist, was so convinced in the perceptive abilities of crows and their relatives that when working with jackdaws, he dressed up as the devil. Stacia Backensto, a master’s student at the University of Alaska Fairbanks who studies ravens in Alaska’s North Slope oil fields, has put together an elaborate costume, complete with a fake beard and a potbelly made of pillows because she believes her face and body are similar to previously captured birds.
Kevin J. McGowan, a Cornell Laboratory of Ornithology ornithologist who has trapped and banded crows in upstate New York for 20 years, said he was frequently followed by birds who had profited from his peanut offerings and tormented by others he had previously trapped.
It’s unclear why crows and other similar creatures are so attuned to humans. Bernd Heinrich, an emeritus professor at the University of Vermont who is known for his books on raven behavior, believes that crows’ apparent ability to distinguish between human faces is a “byproduct of their acuity,” an outgrowth of their unusually keen ability to recognize one another, even after months apart.
Dr. McGowan and Dr. Marzluff feel that this capacity provides an evolutionary advantage to crows and their relatives. “If you can learn who to avoid and who to seek out, that’s a lot easier than continually getting hurt,” Dr. Marzluff said. “I think it allows these animals to survive with us, and take advantage of us, in a much safer, more effective way.”