Ornithologists from Germany and Australia have documented the emergence of a cultural adaptation to urban environments — opening of household waste bins — in wild sulphur-crested cockatoos (Cacatua galerita) and found that the birds spread this behavior through social learning.
A sulphur-crested cockatoo (Cacatua galerita) opening the lid of a household waste bin using one of many different opening techniques; this bird holds the lid with the bill and its left foot; a second bird is observing it closely. Image credit: Klump et al., doi: 10.1126/science.abe7808.
The sulphur-crested cockatoo is a relatively large species of white cockatoo found in wooded habitats in Australia, New Guinea, and Indonesia.
Their distinctive raucous calls can be very loud, which is a result of an adaptation in order to travel through the forest environments in which they live.
They are naturally curious and very intelligent; they have adapted very well to European settlement in Australia and live in many urban areas.
“Like many Australian birds, sulphur-crested cockatoos are loud and aggro, and often act like a pack of galahs,” said co-author Dr. John Martin, a researcher at the Taronga Institute of Science and Learning.
“But they are also incredibly smart, persistent and have adapted brilliantly to living with humans.”
“Australian garbage bins have a uniform design across the country, and sulphur-crested cockatoos are common across the entire east coast. The first thing we wanted to find out is if cockatoos open bins everywhere.”
“In 2018, we launched an online survey across Sydney and Australia with questions such as, What area are you from, have you seen this behavior before, and if so, when?”
“The survey ran for two years and helped us determine how the behavior spread to other cockatoos in Sydney, importantly we’ll be continuing this survey in Spring 2021.”
By the end of 2019, residents from 44 areas observed the bin-opening behavior showing that it had spread rapidly and widely.
The further analysis showed that the behavior reached neighboring districts more quickly than districts further away, indicating that the new behavior wasn’t popping up randomly across Sydney.
“These results show the animals really learned the behavior from other cockatoos in their vicinity,” said first author Dr. Barbara Klump, a researcher at the Max Planck Institute of Animal Behavior.
They also marked around 500 cockatoos with small paint dots at three selected hot spots to enable the identification of individual birds, allowing the researchers to observe which birds could open bins.
It turned out that only around 10% could do so, most of which were males. The rest waited until the ‘pioneers’ opened the garbage bins to then help themselves.
There was one exception, however: in 2018, a cockatoo in northern Sydney reinvented the scavenging technique itself. Birds in neighboring districts then copied the behavior.
“We observed that the birds do not open the garbage bins in the same way, but rather used different opening techniques in different suburbs, suggesting that the behavior is learned by observing others,” Dr. Klump said.
The scientists hope that their findings will also generate a broader understanding of urban living animals.
“By studying this behavior with the help of local residents, we are uncovering the unique and complex cultures of their neighborhood birds,” Dr. Klump said.
The study was published June 23, 2021 in the journal Science.
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Barbara C. Klump et al. 2021. Innovation and geographic spread of a complex foraging culture in an urban parrot. Science 373 (6553): 456-460; doi: 10.1126/science.abe7808
