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How a Garbage-Bin War Schools Humans and Birds

Forget the space race. In Sydney, Australia, the innovation arms race is real. It’s between humans and sulfur-crested cockatoos, and the battle is over the trash.

Native to Australia and frequenting the suburbs, the cockatoos were already known as garbage bandits. They open the lids with an innovative combination of lifting the front, lifting the lid, walking to the side of the can and flipping the lid back. The smart birds learn from each other about behavior, a kind of cultural transmission. This cultural transfer, it turns out, goes both ways. In people’s efforts to protect their waste, they also show cultural transmission and innovation.

It’s “proof that people learn socially from other people what protection methods to use, and that they are clustered geographically,” said Barbara C. Klump, the lead author of a study published Monday in Current Biologyand a behavioral ecologist at the Max Planck Institute of Animal Behavior in Germany.

For a sulfur-crested cockatoo, a garbage can is a big draw. “I’ve seen them eat chicken bones and ham sandwiches, but they really like bread,” said Dr. clump. While the cockatoos prey on carbohydrates, they scatter waste far and wide. The windswept environment then turns a localized garbage incursion into a widespread garbage disaster. It’s no surprise that people want to protect their bins.

In the study, Dr. Klump and her colleagues checked more than 3,000 bins in four Sydney suburbs to see if people had tried to protect their bins from birds. It is not easy. The bins are emptied by a semi-automatic arm on top of the garbage truck. When the truck arrives, it picks up the bin and flips it over, opening the lid automatically to drop the trash into the truck. So no matter what people try to keep birds out, the box should still be able to open.

“I think the most common is just putting something heavy on the lid,” said Dr. clump. “It’s usually a brick or a rock.” Residents also tried to use a rubber hose to scare the birds or to place an object between the lid and the hinges, such as a pool noodle, a stick or shoes, to prevent the cockatoos from flipping the lids open. Some tied a rope to keep the bin from opening all the way—just wide enough to allow trash to run into the truck.

A good defense promotes the game of the birds. dr. Klump has seen cockatoos use both brawn and brains to push bricks off bins to get the prize. It has also changed the behavior of garbage collectors. When they lift a protected container, “they shake it a little bit, and then the rock or stone falls off and then they empty it,” said Dr. clump. Chopsticks or pool noodles fall through the hinges to make emptying easy.

To show that the behavior was socially learned, the scientists looked at the geographic distribution of waste protection and surveyed more than 1,000 residents. Humans and birds have a lot in common. Birds living in close proximity learn to open bins in similar ways, and human neighbors tend to protect their waste using similar methods.

In the study, 172 residents reported monitoring their waste. Because they were people, 64 percent of trash can owners learned about new waste protection methods from other people. While the birds had the upper hand on rocks and rocks, 61 percent of residents protecting their bins changed their strategies. “Bricks seemed to work for a while, but cockies got too smart,” one survey respondents reported. “Neighbors on the other side of the highway suggested sticks. They work.”

The arms race for innovation between humans and birds is “a really exciting idea,” said Sarah Benson-Amram, a behavioral and cognitive ecologist at the University of British Columbia in Vancouver. “It’s really great to see data showing that this is probably what’s happening.”

dr. Benson-Amram studies how animals react to their environment. She thinks this behavior could extend to other human-animal interactions, such as those involving African and Asian elephants that have learned to use their tusks or tree trunks to break through electric fences around crops. The lab of Dr. Benson-Amram studies raccoons, another example of a garbage bandit known for trying to outsmart humans to defend their garbage.

In Australia, it’s the birds’ turn, and when Dr. Klump and her colleagues can show that methods of beating the security of bins also spread among local birds, will really start the arms race. Australians will have to invent new defenses and remain vigilant. It’s never good to be stubborn.