Crows and their relatives — among them
ravens, magpies and jays — are renowned for their intelligence and for their
ability to flourish in human-dominated landscapes. That ability may have to do
with cross-species social skills. In the Seattle area, where rapid suburban
growth has attracted a thriving crow population, researchers have found that the
birds can recognize individual human faces. John M. Marzluff, a
wildlife biologist at the University of Washington, has studied crows and ravens
for more than 20 years and has long wondered if the birds could identify
individual researchers. Previously trapped birds seemed more wary of particular
scientists, and often were harder 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." To test the birds’
recognition of faces separately from that of clothing, gait and other individual
human characteristics, Dr.Marzluff and two students wore rubber masks. He
designated a caveman mask as "dangerous" and, in a deliberate gesture of civic
generosity, a Dick Cheney mask as "neutral." Researchers in the dangerous mask
then trapped and banded seven crows on the university’s campus in
Seattle. In the months that followed, the researchers and
volunteers donned the masks on campus, this time walking prescribed routes and
not bothering crows. The crows had not forgotten. They scolded
people in the dangerous mask significantly more than they did before they were
trapped, even when the mask was disguised with a hat or worn upside down. The
neutral mask provoked little reaction. The effect has not only persisted, but
also multiplied over the past two years. Wearing the dangerous mask on one
recent walk through campus, Dr. Marzluff said, he was scolded by 47 of the 53
crows he encountered, many more than had experienced or witnessed the initial
trapping. The researchers hypothesize that crows learn to recognize threatening
humans from both parents and others in their flock. After their
experiments on campus, Dr.Marzluff and his students tested the effect with more
realistic masks. Using a half-dozen students as models, they enlisted a
professional mask maker, then wore the new masks while trapping crows at several
sites in and around Seattle. The researchers then gave a mix of neutral and
dangerous masks to volunteer observers who, unaware of the masks’ histories,
wore them at the trapping sites and recorded the crows’ responses.
The reaction to one of the dangerous masks was "quite spectacular," said
one volunteer, Bill Pochmerski, a retired telephone company manager who lives
near Snohomish, Wash. "The birds were really raucous, screaming persistently,"
he said, "And it was clear they weren’t upset about something in general. They
were upset with me." Again, crows were significantly more likely
to scold observers who wore a dangerous mask, and when confronted simultaneously
by observers in dangerous and neutral masks, the birds almost unerringly chose
to persecute the dangerous face. In downtown Seattle, where most passersby
ignore crows, angry birds nearly touched their human foes. In rural areas, where
crows are more likely to be viewed as noisy "flying rats" and shot, the birds
expressed their displeasure from a distance. Though
Dr.Marzluff’s is the first formal study of human face recognition in wild birds,
his preliminary findings confirm the suspicions of many other researchers who
have observed similar abilities in crows, ravens, gulls and other species. The
pioneering animal behaviorist Konrad Lorenz was so convinced of the perceptive
capacities of crows and their relatives that he wore a devil costume when
handling jackdaws. Stacia Backensto, a master’s student at the University of
Alaska Fairbanks who studies ravens in the oil fields on Alaska’s North Slope,
has assembled an elaborate costume — including a fake beard and a potbelly made
of pillows — because she believes her face and body are familiar to previously
captured birds. Kevin J. McGowan, an ornithologist at the
Cornell Laboratory of Ornithology who has trapped and banded crows in upstate
New York for 20 years, said he was regularly followed by birds who have
benefited from his handouts of peanuts — and harassed by others he has trapped
in the past. Why crows and similar species are so closely
attuned to humans is a matter of debate. Bernd Heinrich, a professor emeritus at
the University of Vermont known for his books on raven behavior, suggested that
crows’ apparent ability to distinguish among human faces is a "byproduct of
their acuity," an outgrowth of their unusually keen ability to recognize one
another, even after many months of separation. Dr. McGowan and
Dr.Marzluff believe that this ability gives crows and their brethren an
evolutionary edge. "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." Dr.Marzluff is the first scientist to carry out the formal study of human recognition in wild birds.