Geography Reference
In-Depth Information
of gun range in rural areas where an aggressive bird would be wounded or
killed. We do not know whether these cultural changes in crows and ravens
af ect human culture, but annoyance with aggressive city crows is common,
and some cities (for example, Lancaster, Pennsylvania) respond with control
ef orts that may diminish future aggressive tendencies of city crows. In other
settings, people bond with crows almost as closely as they bond with their
pets, feeding them daily. This practice favors tameness and solicitation by
crows that recognize the individuals who provide for them.
City crows seem always to scrutinize us, searching for signs of intent.
Dr. Barbara Clucas discovered that they pay particular attention to our eyes.
If Clucas looked directly at a crow as she approached it, the crow quickly
backed away and even l ew of , something that is rare in the city. But if she ap-
proached the crow with her gaze averted, the crow carried on as if nothing of
consequence had occurred. Casting a stare provides a reliable signal to crows
that an approaching human is watching them. If the staring person is familiar,
the crow may approach for food. If the staring person is unfamiliar, the crow
seems to take the approach as a direct sign of trouble afoot.
The responses of crows to people, be it aggressive or solicitous, has stimu-
lated a radiation of popular culture, from the naming of sports teams and rock
bands to the myriad trappings and tales traditional in American Halloween
celebrations. Coupled interactions between crows and people in cities include
jungle crows scavenging garbage in Tokyo, which prompted improved trash
disposal methods by residents and subsequent novel foraging behavior by
crows; carrion crows in Sendai, Japan, placing walnuts in roads so that cars
crack them open, which encouraged humans to swerve in order to hit the nuts;
and tits and black-billed magpies in Britain opening milk bottle lids, causing
people concerned about disease transmission to change milk delivery meth-
ods. The observed increases in nut-cracking and milk-drinking behaviors have
spread slowly from sites of innovation, as expected with social learning and
cultural evolution, suggesting that human and bird cultures have coevolved.
