Sulfur-crested cockatoos don’t have the best reputation around their human neighbors in Stanwell Park, an affluent suburb an hour’s drive south of Sydney, Australia. The wild animals have flourished in an urban environment, and with their success in the cityscape, they’ve developed some rowdy new habits—like flipping open trash bin lids to access the goodies within. In 2014, this behavior earned the cockatoos a bit of bad press in the local community magazine. Ornithologist Richard Major first learned about the string of bird-brained bin raids in his neighborhood when he was interviewed for the article. At the time, he hadn’t witnessed the crime firsthand yet, but he and his fellow researchers decided to investigate the behavior in 2018.
Now, in a new study published today in the journal Science, the team reports these clever cockatoos can learn this garbage foraging behavior within their social groups, with more birds picking up the skill each year.
“Cockatoos are the punks of the bird world” in both looks and character, says study author John Martin, an ecologist at Taronga Conservation Society, Australia. For starters, the yellow crests they sport resemble mohawks. Their exuberant displays of hopping, wing flapping and head bobbing are easy to mistake for a devil-may-care attitude. Their shrieking calls would enhance any punk rock song. (Martin says flocks of cockatoos “literally scream” every sunrise and sunset.) Their foraging habits are inventive, if not a bit annoying. Curious and destructive, they leave a trail of devastation in their food raids—from beheading flowers for nectar to decimating hordes of fruit just to reach a few seeds.
When Martin, one of Major’s former Ph.D. students, and his colleagues learned about the trash-jacking behavior, they wondered how prevalent it was among other cockatoos and how the brainy birds pick up the action. Three years, 160 direct observations and one large-scale citizen science survey later, the researchers confirmed that the clever cockatoos can learn how to open garbage bins by observing other pioneering parrots. This research is the first of its kind to witness how a stroke of innovation in a few cockatoos propagates a new foraging culture among peers.
“It’s really exciting that [the researchers] were able to catch [bin opening] in real time,” says Alice Auersperg, a cognitive biologist at the University of Veterinary Medicine, Vienna in Austria, who wasn’t involved in the study. She’s particularly impressed with how the researchers tapped into the power of citizen science to document a new behavioral quirk in the wild at large scales. “They had a great approach,” she says.
The researchers documented observations of bin-busting behavior by surveying 1,322 people across 478 suburbs in Sydney and Wollongong for one and a half years. Only three districts had ever observed cockatoos opening bins before 2018, but by 2019, 44 areas reported the behavior. Bin opening spread more quickly to nearby districts than to faraway neighborhoods or communities surrounded by forests, which could have walled off trendsetters from sharing their newly acquired skills.
Since not all cockatoos catch on, the researchers suggest the innovative foraging behavior could be an example of social learning rather than a genetic predisposition. Their learned skill is unlike other avian intelligentsia such as New Caledonian crows, which are evolutionarily wired to tinker with tools whether they were raised in the wild or in captivity.
To analyze the mechanics of bin opening à la cockatoo, the researchers filmed 160 instances of the behavior in three locations. Bribing the birds with sunflower seeds, the team dabbed nearly 500 cockatoo passers-by with temporary paint to tell different individuals apart. (Capturing cockatoos is much trickier—smart birds as they are, they quickly learn to recognize human kidnappers and sound the alarm with their banshee shrieks.)
Busting the bin open is no easy task for a cockatoo, requiring an elaborate sequence of lifting, lid holding, walking and flipping steps. Only eight percent of marked birds—mostly the heavier males—developed the chops to flip open the lids, but the researchers were surprised by the overall persistence in both successful and unsuccessful individuals.
“The ones that can do it make it look so easy,” says study author Barbara Klump, a behavioral ecologist at the Max Planck Institute of Animal Behavior in Germany. “If I hadn’t seen so many birds struggling, I wouldn't appreciate what a difficult task this actually is.”
Among triumphant cockatoos, techniques varied between individuals and even more saliently across geographic locations. Each bird had its own unique way of going about its garbage burglary. Certain cockatoos favored walking clockwise along the bin’s rim. Some rubbish raiders shuffled sideways, whereas others marched headlong as if walking along a tightrope. This result alludes to the existence of regional subcultures among cockatoos. Other animal brainiacs that learn socially and subscribe to cultures of their own include primates, whales and songbirds.
“That’s very exciting for us from an ecological point of view,” Klump says. “In such a human environment, animal cultures can actually facilitate adaptation.”
She adds humans have only themselves to thank—or blame—for the cockatoo’s foraging habits, as they’ve provided lidded bins for the birds to explore in the first place. “It just shows how well-adapted these birds are to the human environment,” she says.
Martin, who lives in Sydney and adores cockatoos, says several flocks squat in his corner of town, each crew around 50 members strong. He has yet to observe bin opening behavior in his district, but he anticipates it could catch on eventually. Only time will tell, of course, but the probability is certainly not out of the question. “There are lots of birds,” he says, “and every house has bin.”