A collaborative study proves that cockatoos living on the outskirts of Sydney, Australia, can learn a new skill through social communication: flipping through bins in search of extra food. A team of researchers from Barbara Klump and Lucy Aplin of the Max Planck Institute for Animal Behavior in Germany, as well as John Martin (Taronga Conservancy) and Richard Major (Australian Museum), have shown that this behavior of cockatoos is actually acquired, not a genetic one.
A sulfur-crowned cockatoo opens the lid of a family trash can.
Source: BARBARA KLUMP/MAX PLANCK Institute for Animal Behavior
A few years ago, Richard Major, senior principal research scientist at the Australian Museum Institute, and veteran author Lucy Aplin shared a video showing a sulfur cockatoo opening a trash bin with the lid closed. The cockatoo lifts the heavy lid with its beak and claws and then drags it over along the sides, earning food rewards such as fish heads, sandwiches and fruits.
One of the main participants in the new study, Barbara Klump, a behavioral ecologist at the Max Planck Institute for Animal Behavior, was fascinated by the video, "It's so exciting to observe such ingenious and innovative ways of accessing food resources, and we have to systematically study this unique foraging behavior," Klump said.
Barbara Klump and her colleagues twice organised questionnaires of residents around Sydney in 2018 and 2019, asking if residents had seen such behaviour – and if so, when and where. More than 1,300 people responded. Prior to 2018, parrot capping incidents were reported in only three suburbs. By the end of 2019, 44 of the nearly 500 people surveyed said they had seen it. The researchers concluded that there is a clear pattern of this spread: it begins near these three initial suburbs and gradually weakens as the site gets farther away. Klump said this shows that the birds are learning from each other and spreading the behavior throughout the city.
One sulphur-crested cockatoo holds the lid with its beak and left foot, and another parrot is watching live.
© MPI of Animal Behavior/ B. Klump
To get a clearer picture of the cockatoo's behavior patterns, the researchers captured and labeled 486 parrots in some hotspots with open bins. It turns out that only about 10% of parrots can do it, most of them males. The rest of the parrots waited until the "pioneers" opened the trash can before they began to "rub rice". After 160 successful shots of lifting the lid, they noticed a few common steps: First, a parrot used its beak to lift the front corner of the lid, and then they staggered toward the hinge to open it slightly. Finally, they abruptly lifted the lid and left it fully open, revealing a "treasure chest" that might contain food.
Some parrots use slightly different techniques: some grip the handle of the can lid, while others hold only the lid itself. Some parrots hold it with both their mouth and feet, while others use only their mouths. The greater the geographical distance of the capping behavior, the greater the technical differences in birds. In the northern suburbs of Sydney, far from the three initial areas, the act of lifting the bin lid seems to have suddenly appeared on its own, suggesting that a new group of cockatoos have "independently developed" this new method of foraging.
"It really means they're learning in society, not just to open the trash can to find food, but also how to open it." It also shows that local knowledge about dumpsters is passed on, creating a 'regional subculture'". Klump said. Local cultures or "dialects" have been found in parrot calls, but this is the first time it has been found in parrot foraging. This means that the cockatoo joins a "club of advanced animals", such as some primates and whales, which have a local culture in terms of communication and food gathering.