June 19, 2013
Written by Jack Sanders
Thursday, 04 September 2008 15:31
Many people have remarked on the story that appeared in last week’s New York Times about a scientist’s discovering that crows can recognize individual human faces, but a perhaps more remarkable account of crow intelligence appears in the current issue of Bird Watcher’s Digest.
It’s long been known that the corvids — crows, ravens, magpies, and jays — are quite smart, doing things like using tools and employing automobile traffic to break open nuts.
The Times story told of a wildlife biologist at the University of Washington who did an experiment in which crows on campus were trapped and banded by students wearing a “caveman” rubber mask. A Dick Cheney mask was used as a “neutral” mask by students not involved in the trapping.
In the weeks and months that followed, student volunteers who walked around campus with caveman masks were yelled at by the crows, which ignored the Cheney-masked students. Two years later, the number of crows recognizing the caveman mask as dangerous had spread to many birds that had never been trapped, indicating that parents and others in the community had taught offspring that this was a dangerous face.
In the current Bird Watcher’s Digest, columnist David Bird (yes, his real name — he’s a professor of wildlife biology at McGill University in Toronto) recounts an experience witnessed by ornithologist Russ Balda, which appeared recently in The Wilson Journal of Ornithology.
Mr. Balda was watching a crow eating seeds on a large platform feeder in Flagstaff, Ariz. Unlike other birds that came and went, the crow just stood there, hogging the feeder.
A Steller’s Jay landed on the edge of the platform and started scolding the crow for about 10 seconds. The crow ignored the pest, so the jay got closer and started making feinting movements at the crow. The crow then turned and faced the jay, which backed off.
The crow resumed eating, but the jay kept returning and repeating its harassment performance. Then the jay tried aerial techniques, swooping down on the crow a couple of times, without actual body contact.
After that didn’t work, the jay did something that astounded Mr. Balda. It flew to a mahogany tree and broke off a twig about four inches long. With the twig in its mouth and the narrow end pointed outward, the jay landed on the platform and lunged at the crow, narrowly missing it with the stick.
The crow jumped toward the jay, which dropped the twig and moved backward. The crow then picked up the twig and lunged at the jay!
The jay then took off, followed by the twig-wielding crow in hot pursuit.
In effect, and perhaps in fact, both the jay and the crow were employing a weapon — perhaps the first time this kind of “combat” has ever been observed, at least, by a scientist.
Weapon use of a different sort — bombing — has been observed in a couple of species. Professor Bird points out that Black Eagles have been recorded dropping sticks on the heads of intruders to their nests. “A female American Crow was observed dropping pine cones, not once but three times, onto the head of a human climber ascending to its nest,” he said.
Corvids’ using tools has been widely reported, and of course, a weapon can be considered a form of tool, but the Flagstaff indicate was different.
“Balda’s observation may indeed be the first incident of a bird holding an object in a weapon-like fashion to undertake an aggressive action against another bird,” Professor Bird said.
He adds, “It was a pity that the crow did not have its own stick to duel with the jay.”
HawkWatch Weekend Festival, bird-themed workshops, walks, games, shows, raptor counting, ‘green’ vendors, and much more, Sept. 13 and 14, Audubon Greenwich and Quaker Ridge Bird Club, 613 Riversville Road, Greenwich, 203-869-5272 x239.
Fall Bird Migrants, hike, Saturday, Sept. 27, 7 to 8:45 a.m., Audubon Greenwich, 613 Riversville Road, Greenwich, 203-869-5272 RSVP to store at x221.
Raptor ID Made Easy, with Ken Mirman, Saturday, Sept. 27, 11 to noon, free, Audubon Greenwich, 613 Riversville Road, Greenwich, 203-869-5272 RSVP to store at x221.
Hook Mountain Hawk Watch, across the Hudson, includes half-mile hike, Saturday, Oct. 18, 9 to 2:30, Bring lunch, water bottle, hiking shoes, hat, and binoculars, Audubon Greenwich, 613 Riversville Road, Greenwich, Ted 203-869-5272, x230 to register.
Jamaica Bay Wildlife Refuge, trip, Saturday, Nov. 1, 9 a.m. to 3 p.m., Audubon Greenwich, 613 Riversville Road, Greenwich, Ted 203-869-5272, x230 to register.
Winter Birds and Project Feederwatch, how your family can be “citizen scientists” to help count winter birds at bird feeders in the backyard, Saturday, Nov. 8, 1:30 to 3 p.m., Audubon Greenwich, 613 Riversville Road, 203-869-5272 RSVP to store at x221.
Bird Watching Cruises on Long Island Sound and Norwalk Harbor, with Larry Flynn, wildlife conservationist, Saturdays from 7:30 to 10:30, aboard 40 passenger ferry, $20, Norwalk Seaport Association, from Seaport dock, Water Street, 203-838-9444, www.seaport.org.
Bird walks with Luke Tiller, mostly Saturdays at 8 a.m., $10 each; to register, www. sunrisebirding. com/ walks.htm; 203-981-9924, luke.tiller @ gmail.com.
First Sundays, birding at Greenwich Point with Meredith Sampson of Wild Wings, and other guides, meet at the second concession stand, 203-637-9822.
Copyright (c) 2008 by Jack Sanders. Send sightings or comments to: jackfsanders [at sign] yahoo.com, or to Bird Notes, Box 1019, Ridgefield, CT 06877; or call 203-438-1183, extension BIRD (2473), and leave a message with your report, spelling your first and last names and telling us your town. If you need help identifying a bird, try your local nature center. If you find an injured bird, call wildlife rehabilitator Darlene Wimbrow of Redding, 203-438-0618, Wildlife in Crisis of Weston, 203-544-9913, or Wild Wings of Greenwich, 203-637-9822. The columnist’s website is www. sandersbooks. com.
|< Prev||Next >|
The requested URL /components/com_nklf/tent.php was not found on this server.