As It Happens

Clever cockatoos are teaching each other how to open trash bins in Australia 

Sulphur-crested cockatoos in Australia are teaching each other how to pry trash bins open, and the phenomenon is rapidly spreading. 

Scientists say they’ve documented an emerging ‘cultural trend’ among the sulphur-crested cockatoos 

A sulphur-crested cockatoo opens the lid of a trash can in Sydney, Australia. (Barbara Klump/Max Planck Institute of Animal Behavior/The Associated Press)

Richard Major was driving to work one day when he saw something unusual — a cockatoo opening a garbage bin. 

Major, a bird ecologist at the Australian Museum Research Institute in Sydney, had seen the urban animals feasting at the trash bins many times before, but he'd always assumed they'd been left open. So when he noticed the same thing happen again, he decided to pull over for a closer look.

"I stopped the car and parked it on the other side of the road, got out, closed the rubbish bin lid, and the bird flew up to the telegraph wire," he said.

"But no sooner than I had popped back in my car, it just flew back down to the lid, and just as easily as anything, lifted it up, walked along and flipped it over the back again. So I thought, wow, this is an amazing, amazing behaviour, how easily it did it."

But this wasn't a lone crafty cockatoo. Major is one of the researchers on a study published last week in the journal Science, that found sulphur-crested cockatoos in Sydney are teaching each other how to pry open trash bins— and the phenomenon is rapidly spreading. 

One cockatoo lifts the lid of a trash can while several others watch. Scientists say the birds are teaching each other how to open the bins. (Barbara Klump/Max Planck Institute of Animal Behavior/The Associated Press)

Sulphur-crested cockatoos, a type of parrot, are known for their intelligence and adaptability. Major says their populations have swelled in Australian cities in recent decades, thanks largely to the abundant supply of food waste.

"They're really large, they're loud, they're quite flamboyant, but they're also really smart and they're persistent and they've adapted brilliantly to living with humans," he said.

Major captured the Sydney cockatoos' dumpster-diving shenanigans on camera, and sent it off to his colleague Lucy Aplin, a cognitive ecologist at Max Planck Institute of Animal Behavioral in Germany, and co-author of the study. 

She was intrigued and recruited Max Planck Institute behavioural ecologist Barbara Klump to lead the research.

The team carried out the study in three steps. First, they drove around Sydney on garbage collection days and documented the birds doing their thing. Then, they conducted a community survey, asking Sydney residents where they had seen this behaviour. Finally, they painted markings on the birds to document exactly which of them were opening the bins. 

Their biggest takeaway was that the phenomenon was spreading — and fast.

At the start of the study in 2018, the behaviour had only been spotted in three suburbs south of Sydney. By the end of the study in 2019, it had been observed in 44 suburbs. 

"That was indicative that the birds were learning something," Major said. "It wasn't something that was just randomly popping up all over the place."

The scientists documented what they called an emerging "cultural trend" among the Sydney cockatoos. That's a rare feat for animal scientists, because it doesn't happen very often, and you have to be in the exact right place at the right time to see it.

"This is a scientist's dream," said Aplin. 

A sulphur-crested cockatoo watches as another opens a trash can. Researchers say the birds who perform the clever feat are at the top of the social hierarchy. (Barbara Klump/Max Planck Institute of Animal Behavior/The Associated Press)

The team also learned that only about 10 percent of the cockatoos actually open the bins, while the rest watch and wait for a chance to dive in and start snacking. 

The birds that performed the trick tended to be male, and have higher dominance in the birds' social hierarchies.

"This suggests that if you're more socially connected, you have more opportunities to observe and acquire new behaviour — and also to spread it," Klump, the lead author, said.

And cockatoos in different areas of the city use different techniques to open the lids, and teach those unique methods to other cockatoos in their social groups. 

"We were able to find … that little differences in subculture occurred between populations," Major said. "The bin opening in each subculture appeared to be learned by cockatoos watching each other."

Major noted that while the birds' bin behaviour is fascinating to watch, it's also quite a nuisance for Sydney residents. 

"They are very messy in that, in order to get food, they just turf all the rubbish out of the rubbish bin to get down to it," he said.

"In terms of their destructive behaviours, it's a warning to people that if they want to stop it, don't think it's cute and encourage it for a little while. Stop it in its tracks as soon as you see it, because we know once this behaviour occurs, it will spread quickly within their social groups."

But stopping it is easier said than done. Some folks, he said, have tried putting heavy rocks on the bins to keep the birds out, but the clever creatures simply push them aside. 

He's curious to see how they adapt as people devise new methods to bird-proof their bins. "It's an interesting space for further observation, he said. 

Written by Sheena Goodyear with files from The Associated Press. Interview with Richard Major produced by Niza Lyapa Nondo.

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