Human-wildlife relationships are a little different Down Under. Rather than worry about hitting a deer, Aussie drivers fret about kangaroo and wallaby collisions. And instead of guarding their trash cans against raccoons, Australians must stay vigilant against sulfur-crested cockatoos breaking into their bins.
It’s gotten so bad that many suburban residents have cobbled together makeshift protections against the birds, everything from a rubber snake to act as a scarecrow, to a pair of shoes affixed sideways to prevent the can from opening fully. One homeowner went viral in a private Facebook group after she shared her method of deterring the birds, which consisted of a pair of full water bottles zip tied to the bin’s handles.
“Guaranteed if a bin lid is even one centimetre ajar, the cockys will open and flock onto the bin, it’s quite intimidating up close,” one Facebook user commented.
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Barbara Klump, a behavioral ecologist at the Max Planck Institute of Animal Behavior in Germany, noticed these jury-rigged creations a few years ago when she was researching the birds’ behavior. The study she ultimately published in 2021 showed that the cockatoos were teaching each other how to open the bins and that the activity constituted a form of cultural exchange since the birds weren’t breaking into the bins out of necessity but rather for fun. But Klump also wanted to understand how people were reacting to the birds’ newfound skill.
“The cockatoos make a lot of mess, so of course people are inclined to stop them from getting into their bins,” she told The Daily Beast.
Klump’s new research, published Monday in the journal Current Biology, looks into the different methods of garbage bin protection, and how these different innovations have become more effective over time and spread throughout a neighborhood. The parrots have begun to outsmart some of these methods, including knocking off bricks placed on top of garbage bin lids (“It's quite amazing how hard they work to push it off, but they do succeed,” Klump said.) Klump and her co-authors wrote that these conditions could mark the beginnings of a highly unusual inter-species arms race between cockatoos and humans.
In the study, Klump surveyed Australians on where they lived, what kinds of protections they used, and how long they have used these methods. She and her team classified these deterrents into groups based on their efficacy, from modifications that did not affect the bin’s function, such as rubber snakes, to highly effective methods like the viral water bottle hack. Importantly, Australians cannot simply padlock their bins, since they must be able to be emptied to be useful, but from 2015 to 2019, more and more residents reported using some type of bin protection. Not only that, their methods are getting more effective over time while the birds are getting better at breaking into low-level protections—a hallmark of an innovation arms race.
The researchers also found a correlation between the presence and type of innovation, and those same innovations from a neighbor—meaning that if your neighbor did something to stop the cockatoos, chances are you would, too. Even so, distance as the crow flies was less of a factor in copying a neighbor’s innovation than “street distance,” or the route one would take by walking or driving to a neighbor.
Klump said that she’s watching the arms race unfold intently, as she doesn’t know what will happen down the road.
“You could imagine that in the future [the cockatoos] figure out how to solve the higher-level [protections] and then the humans would come up with something even better and it could just go on and on,” she said. Or, perhaps one side or both will lose interest in the conflict and reach an uneasy truce.
The researchers asked a subset of survey respondents who changed their protection measures why they did so and received some colorful responses. The study quoted one resident about their strategy in the arms race, which has no end in sight:
“Bricks seemed to work for a while, but cockies got too clever. Neighbours on other side of highway suggested sticks. They work.”
