Wild cockatoos learn to open bins by copying others—first evidence of social learning

Parrots can mimic human speech, move in time to music, and even help others in need. Now, research shows that these large-brained birds can also learn new behaviors from each other, which only decades ago was thought to be a uniquely human trait.

In Sydney, Australia, some sulfur-crested cockatoos—a noisy, gregarious bird that’s common in eastern Australian cities—have figured out how to open garbage bins, a behavior that other cockatoos quickly copied, allowing them to exploit a new food resource.

This discovery means that parrots “have joined the club of animals that show culture,” says behavioral ecologist Barbara Klump, leader of the study that appears this week in the journal Science.

Other social species with long lives and big brains, such as crows, great apes, and cetaceans, practice such so-called foraging culture—for instance, chimps show each other new ways to open nuts. “You would expect parrots also tick all these boxes, but we didn’t have evidence for it”—until now, says Klump, a National Geographic Explorer who is on staff at Germany’s Max Planck Institute of Animal Behavior. (Read about the hidden world of whale culture.)

Part of the reason for that lack of evidence is that while parrots in captivity are well studied—think Alex the African gray parrot, who had the intelligence of a three-year-old—it’s harder to observe cultural behavior in wild parrots. For one thing, in a wild landscape it’s difficult to account for all the factors that might be influencing birds’ actions.

But because Sydney’s sulfur-crested cockatoos reliably frequent the same garbage bins, that provided an ideal study setup for Klump to observe these cheeky “urban explorers,” she says.

These handsome, two-foot-tall white parrots with vibrant yellow head crests are native to eastern Australia and nearby Pacific islands. Unlike most of the 350 known parrot species, the sulphur-crested cockatoo is flourishing, particularly in urban environments. But they’re often regarded as pests in those settings due to their destructive habits, such as chewing on balconies.

People who study parrots aren’t necessarily surprised by the social-learning discovery, says Timothy Wright, a New Mexico State University biologist who studies vocal learning in parrots and wasn’t involved in the study. Still, Wright says, the research furthers our understanding of parrots as highly intelligent beings.

“I like to call parrots the most human of birds,” he says, “and this is more evidence in that direction.”

Predictable pattern of cockatoo learning

In the mid-2010s, scientists started hearing about cockatoos opening trash cans in Sydney’s southern suburbs. “The interesting part was the resource is everywhere, the birds are everywhere, but we didn’t see the behavior everywhere,” Klump says. (Read about the emerging science around bird intelligence.)

She and her team launched an online survey in the greater Sydney and Wollongong areas, asking people whether their resident cockatoos could open bins. People from about 400 suburbs responded.

The first survey, in 2018, confirmed people in three southern suburbs had noticed the birds prying open their trash bins with their beaks and claws. By the end of 2019, surveys showed the behavior had spread to 44 suburbs. Plotting the data on a map revealed that the behavior radiated outward in a predictable pattern—a clear indication, Klump says, that the bin opening was learned and not random.

Over time, the birds developed various techniques for wrenching open the lids, such as using their feet or beaks in different ways. This is evidence of regional subcultures, the study says. (Learn how Australia’s palm cockatoo uses a tool to make music.)

In the course of the study, the scientists spent time habituating themselves to some 500 suburban cockatoos. Once the birds were accustomed to their presence, the scientists used makeup sponges to smudge dabs of nontoxic paint on the birds’ feathers, so the researchers could track which individual animals could open bins.

Of those 500 that had been marked, only 10 percent could open bins. Most of them were males—possibly because males are more dominant in the sulfur-crested cockatoo social hierarchy, or because males are larger and therefore more physically able to pull open the lids, Klump says. The behavior wasn’t more prevalent in any age group, with young birds just as talented at bin opening as older ones.

Crowdsourced science

The study “demonstrates very clearly that cockatoos… can and do shift their feeding behaviors to exploit new resources. And that the behavior is transmitted and sustained through time—at least over the course of this study,” says Daniella Teixeira, an ecologist at Australia’s University of Queensland who studies Australian cockatoos.

She says the research “gives us some hope” that endangered cockatoo species could similarly learn new ways to find food and share this knowledge with peers, she says. Those endangered species include Australia’s southeastern red-tailed black cockatoo, which numbers fewer than 1,500 in the wild.

Teixeira also praises the study for using citizen, or community, science as a research tool for studying wild parrots. “It’s cool to see this spread of behavior in a short amount of time, and even cooler that it’s done through citizen science,” she says. “It’s a novel approach.” (Read how more people are noticing nature around them during the pandemic.)

This crowdsourcing, as well as the scientists’ non-invasive technique in color-marking the birds, also impresses Wright. “The study as a whole is pretty ingenious for using those various approaches,” he says, particularly on little-studied wild parrots.

“We’ve always known in our hearts,” he says, “that parrots are pretty smart animals.”