Cockatoos Are Getting Smarter. Should Humans Be Worried?

STANWELL PARK, Australia—Outside a local cafe, a sulphur-crested cockatoo perched on a garbage bin, trying to open the lid. Another loitered nearby, waiting to see if its companion found tasty morsels in the trash.

The birds, a type of parrot that is native to Australia, were acting out a common scene in this beachside suburb. There was a lock on the bin, but it seemed either broken or not properly closed. Coffee cups littered the street.

“It is chaos every Tuesday morning,” said Grant Drinkwater, 61, who has experimented with various devices to stop cockatoos from getting into his bins, which are collected that day each week. “Some people put bricks on top of their bins, but the cockatoos just push them off with their nose.”

This otherwise idyllic coastal neighbourhood is Ground Zero for what scientists call a potential “innovation arms race” between humans and cockatoos battling for control of the area’s garbage bins. As the cockatoos figure out ways into people’s bins, the humans respond with evermore elaborate devices to protect their garbage.

Trashy encounters between man and beast aren’t uncommon, as any suburban resident who has tried to keep raccoons out of the rubbish can attest. But in Australia, the age-old tension has reached wild heights.

The unusual bird bin-opening, a behaviour which scientists believe developed only in recent years, is now the subject of rigorous academic study. Researchers say it’s a unique opportunity to investigate how two species can learn—that is, cockatoos teaching others how to get into bins or people swapping bin-protection methods with their neighbours—to quickly adapt to what the other is doing.

Many days, the cockatoos seem to be winning.

Mr. Drinkwater thought he had a solution: He attached a piece of wood to the underside of his bin lid, which he figured would make it too heavy for the cockatoos to lift. It worked until the lid snapped off during trash collection one week, when a garbage truck used a robotic arm to grab the bin and turn it upside down.

He then switched to using a brick, but the cockatoos knocked it out of the way, got into the bin and threw trash all over the street. Now, he wedges a plastic drink bottle in the hinge of the lid, which he says prevents the birds from fully flipping it open. But some of his neighbours still have their guard down. On a recent trash day, an unprotected bin on his street was hit.

“It was a demolition derby,” said Mr. Drinkwater, recalling one particularly bad morning when cockatoos tossed garbage everywhere.

To open a bin, a cockatoo generally uses its beak and foot to lift the lid, shuffle along the side of it and then flip it over. Only a small percentage of cockatoos can flip the lid, but once it’s open, other birds dive in to search for food.

In a recent study, scientists found 52 different ways that people protected their bins from cockatoos. That ranged from weighting the bin lids to shoving old sneakers or a pool noodle in the hinge to fitting specially designed commercial latches onto the bins that residents call “cockie locks.”

In one case, someone tried to scare away the cockatoos with a rubber snake. Another person installed spikes to prevent the cockatoos from landing.

“I was just super excited about the variety,” said Barbara Klump, a behavioural ecologist at the Max Planck Institute of Animal Behavior, a scientific research institute in Germany, who led the research. “Originally I thought, ‘How many methods can there be to block the access to a bin?’ ”

The researchers grouped the bin-protection devices into multiple categories based on their sophistication, and confirmed the birds could defeat “low efficacy” methods like a rock on top of a bin. The study, published in the scientific journal “Current Biology,” included a picture of a cockatoo pushing away a brick.

Employing what they called a “spatial network approach,” the scientists found there were clusters of bins with similar protection methods. They also used data from an online survey to develop a mathematical model to show how human countermeasures changed over the years.

The cockatoos are good problem solvers, said Richard Major, a bird ecologist at the Australian Museum, a museum of natural history in Sydney. They generally eat a lot of grass seeds, roots and berries, but clearly aren’t picky. Dr. Major said he’s seen a cockatoo eating a chicken drumstick, and another gorging on what looked like a whole baked fish carcass.

“They’ve actually started to work in packs,” said Edith McNally, a retired school principal, who often sees cockatoos rummaging through bins on her morning walks in the neighbourhood. “It’s like gang warfare.”

Residents say the key is to prevent the birds from flipping the lid, which allows other birds to raid the bin. But the defences still have to allow the bin lid to open for the garbage truck. Ms. McNally, 73, tried wedging a broom handle into the lid’s hinge, but the handle sometimes fell into the garbage truck when the bin got tipped upside down.

Now she uses a cockie lock, which she says seems to be effective. One Australian company that makes the locks, Secure-A-Lid, says it uses a “gravity-release design mechanism” that disengages the main latch when the bin is tilted by garbage collectors.

Owner Brett Sweetnam was inspired to develop the device after his bins were raided by cockatoos, though it can protect against any creatures that might rummage through the garbage, he said.

Scientists say more research needs to be done. Dr. Klump and her colleagues are still running a survey to see if the bin-opening behaviour spreads to other areas.

Cate Bridgford, 22, who works at the cafe where the cockatoo was trying to open the bin, said that one time, the birds tossed soiled baby diapers from the garbage all over the ground.

“I don’t get mad at the birds. The birds, they just do what they do,” she said. “Those are our raccoons.”