The bird can grab the lid of a trash can with its beak, open it, and then fly along the edge of the bucket far enough for the lid to fall back, revealing the edible treasures inside.
Cockatoos in Sydney have learned how to open trash buckets — and the technique is gaining momentum as others have learned to do so by watching them, scientists say.
Australian sulfur-tailed cockatoos were first spotted by ornithologist Richard Major several years ago when he was opening trash can lids in search of food.
Impressed by their ingenuity, Mr. Major and researchers from Germany studied how many cockatoos had learned this trick.
The team recorded the phenomenon in three Sydney suburbs in early 2018 and found that it had spread to 44 suburbs by the end of 2019.
After analyzing video footage of 160 nimble birds lifting trash can lids and assessing geographic distribution, they concluded that most birds learned by watching others.
It’s quite a feat for birds to grab a trash can lid with their beak and open it.
Then they must advance far enough along the edge of the trash can for the lid to fall back, revealing the edible treasures inside.
Mr. Major said the “fairly rapid spread” was not accidental, but “started in the southern suburbs and spread further.”
In other words, the birds learned the trick by watching their congeners. And, in fact, it became a popular dance
Scientists have documented other examples of social learning in birds, such as blue tits learning to pierce the foil lids of milk bottles in Great Britain from the 1920s.
Lucy Eplin, a cognitive ecologist at the Max Planck Institute for Animal Behavior in Germany and a co-author of the study, says that real-time observation of the spread of a new “cultural trend” in the wild — or in the suburbs, in this case — has given cockatoo researchers a special opportunity.
“It’s a scientist’s dream,” she said.
On a day of scavenging in suburban Sydney in the summer of 2019, her colleague Barbara Klump filmed about 160 successful bird attempts.
Most were males, which tend to be larger than females and also likely dominate the social hierarchy.
Ms. Klump said: “This suggests that if you are more socially connected, you have more opportunity to observe and acquire new behavior and to spread it.”
Cockatoos are extremely gregarious birds, feeding in small groups and sleeping in large groups, and they are rarely seen alone in Sydney.
While the numbers of many animals have declined with the growth of Australian cities, these bold and colorful birds are generally thriving.