Cockatoo tricks for trash

Cockatoos may have bird brains, but at least some of them are learning to dumpster dive. A group of researchers on July 23 published a study in the journal Science presenting evidence that some of the parrots had learned foraging techniques from watching other birds, and argued it demonstrated a rudimentary bird culture.

Australian ornithologist Richard Major noticed sulphur-crested cockatoos pillaging his garbage bins a few years back. He said the cockatoos in the Sydney, Australia, suburbs use their beaks to lift the lid, and then walk back toward the hinge to open it, allowing them to feast on trash.

By 2018, Major teamed with a group of other scientists to study how many other birds knew the trick. They created a survey to ask residents in the Sydney area if they had seen the parrots do something similar. Initially, the team of researchers uncovered reports of cockatoos dumpster diving in just three suburbs. But by the end of 2019, the team had fielded reports of cockatoos prying open garbage lids in 44 suburbs in the Sydney area.

“From three suburbs to 44 in two years is a pretty rapid spread,” Major said. “That spread wasn’t just popping up randomly. It started in southern suburbs and radiated outwards.”

To Max Planck Institute behavioral ecologist and study co-author Barbara Klump, that meant the cockatoos were likely learning from watching one another. She set up video cameras near garbage bins and recorded 160 instances of the birds getting into the trash. Most of the dumpster-diving cockatoos were males, which are larger and more powerful than the females. But Klump said the males getting into the trash also tended to be at the top of the birds’ social hierarchy.

“This suggests that if you’re more socially connected, you have more opportunities to observe and acquire new behavior—and also to spread it,” she said.

Klump and her colleagues noticed something else. As the behavior spread through Sydney’s population of cockatoos, techniques for accomplishing the task diverged into regional patterns. One group might lift the lid with just their bill while others used both their bills and a foot. The researchers compared the subculture to a regional dialect.