Credit: iStockPhoto
PARIS: Humans who dismiss birds as featherweights may revise their opinion when learning of crows that can not only identify the face of someone who is a danger but also teach others about the threat.
Intrigued by the behaviour of wild American crows (Corvus brachyrhynchos) on their campus in Seattle, University of Washington scientists explored whether the birds would recall a face associated with a frightening ordeal.
The researchers donned the rubber mask of a caveman before trapping, banding and releasing seven crows.
Thereafter, researchers wore either this 'dangerous' mask or a neutral one - that of former U.S. vice president Dick Cheney - and observed, as they walked along the college paths, how the flock of crows reacted.
Which faces were scolded?
The 'crow magnon' mask prompted the birds into a collective response to a threat. They cawed and screeched, angrily flapped their wings and flicked their tail to warn of the danger, a behaviour called scolding.
But the Cheney mask elicited no response.
The team broadened the experiment to four other sites beyond the university, this time using different masks made in latex by a mask maker. The faces were ordinary looking, either male or female, Asian or Caucasian. Forty-one birds were caught and banded.
As time passed, the number of birds scolding the 'dangerous' face did not decline. Rather, the reverse happened.
Watching their parents
At the university site, scolding rose from 20% of the birds after the banding to an astonishing 60% after five years.
"At the other sites, we only tested for a half year and there, 20 to 40% of crows scolded," John Marzluff, a professor of wildlife science, said.
What caused the increase in scolding? Some of the angry birds were the offspring of banded crows, who as fledglings had watched as their parents reacted to the perceived danger.
But there were also unbanded crows, living up to 1.2 km from the site. They joined in, apparently learning of the threat through the contagion of mobbing.
"Crow Magnon" !! Awesome.
"Crow Magnon" !! Awesome. Maybe follow up with a study using Stephen "Jay" Gould or Dan "Quail" masks.....Actually should've done the capturing phase with the Cheney mask, preferably in his favourite park!
Hmmm
Had I been the crows, the Cheney mask would have scared the living bejeesus out of me. The cro-magnon mask not so much.
Crows
My naughty teenage cousin killed a crow with a catapult one day in late 1960s. He was scolded and attacked by a mob of crows wherever he went for months and even for years until we moved home when our father got a new job. We knew even then that crows taught each other or learnt from one another. They remembered and recognised people who had hurt them. And they took revenge on their enemies viciously. We call some families "the crow tribe" because they always look out for each other. They also remember who are kind to them. In the Regent's Park London a few years ago, I started feeding crows after having seen a couple feeding them daily. Whenever a lone crow saw me entering the park, he would call for his whole gang. And the one who alerted the others often seemed to sacrifice itself by not eating the very first bread crumbs. In fact it often did not have any because the others who arrived late ate all the food. And the number of crow who recognised me grew days by days. Some crows walked with me even though I did not bring food on some days. They are so intelligent. You already know that they can count while some slow humans can't!!!
crows
Clearly crows are much smarter than liberals--but we already knew that!