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YESTERDAY, WE BEGAN sharing tidbits from a recent Live Q&A Chat, part of the online Members Community of the American Association for the Advancement of Science. The subject was corvids, the genus of birds including crows, ravens, jackdaws, and rooks; the Q&A’s authority was the University of Washington Professor John Marzluff.
Do Corvids Use Tools? Professor Marzluff responds in the affirmative: “Tools are habitually used by New Caledonia crows and there is evidence in this species that an innate preference to craft tools is honed by experience with and observation of a parent bird.”
“Other crows occasionally use tools,” Marzluff says, “most famously perhaps is the use of cars to crack nuts by carrion crows in Japan.” These crows place the nuts in roadway crosswalks and then wait until red traffic lights to retrieve the crushed meal.
“In that case” Marzluff says, “the behavior was copied by conspecifics and spread gradually over a decade or so from a point of innovation.”
As described in Wikipedia, “Researchers have discovered that New Caledonian crows don’t just use single objects as tools; they can also construct novel compound tools through assemblage of otherwise non-functional elements.”
Do Corvids Play Games? Wikipedia writes, “Young corvids have been known to play and take part in elaborate social games. Documented group games follow ‘king of the mountain’ or ‘follow the leader’ patterns. Other play involves the manipulation, passing, and balancing of sticks. Corvids also take part in other activities, such as sliding down smooth surfaces.”
Wife Dottie offers experience of a ‘peek-a-boo’ game played with a crow in front of our house. The crow would hide behind her car, then hop out into view. Wife Dottie would acknowledge its presence, move to the other side of the car, and the crow would follow suit.
She recalls watching corvid pairs racing from tree to tree in our backyard, complete with other crows cheering for the two competitors.
Professor Marzluff’s Advice on Working with Corvids. “Actually,” he says, “crows are pretty easy to work with…. They adapt quickly to the confines of a lab, eat just about anything, and as long as they have conspecifics to interact with behave quite normally under unusual situations. However, they learn immediately!”
“So,” he continues, “if you do decide to work with them, and I hope you will, get a good assortment of masks (corvid ones, not covid ones!). You need full face coverings like used on Halloween.”
“We have an assortment,” Marzluff says, “and if you use one when you catch, draw blood, or otherwise challenge the birds, they learn to fear that ‘person.’ But if you wear another when you interact with the birds neutrally (to observe) or positively (to feed), then they learn to recognize that person as friendly and nonthreatening.”
“On my campus,” Marzluff recalls, “the crows know me as dangerous when I wear a caveman mask that we caught a few with 14 years ago. They have passed this on to new generations of birds who were not born when we did our capturing. But if I go out without a mask, they have no fear of me and I can observe them at close range without issue.”
A most informative Q&A Chat. Thanks, Professor Marzluff; and thanks, AAAS. ds
© Dennis Simanaitis, SimanaitisSays.com, 2020