Bruce is a kea, a species of parrot found only in New Zealand. He is about 9 years old, and when wildlife researchers found him as a baby, he was missing his upper beak, probably because it had been caught in a trap made for rats and other invasive mammals the country was trying to eliminate. This is a severe disability, as kea use their long and curved upper beaks for preening their feathers.
But Bruce found a solution: He has taught himself to pick up pebbles of just the right size, hold them between his tongue and his lower beak, and comb through his plumage with the tip of the stone. Other animals use tools, but Bruce’s invention of his own prosthetic is unique.
Researchers published their findings in the journal Scientific Reports. Studies of animal behaviour are tricky — the researchers have to make careful, objective observations.
“The main criticism we received before publication was, ‘Well, this activity with the pebbles may have been just accidental — you saw him when coincidentally he had a pebble in his mouth,’” said Amalia PM Bastos, an animal cognition researcher at the University of Auckland and the study’s lead author. “But no. This was repeated many times. He drops the pebble, he goes and picks it up. He wants that pebble. If he’s not preening, he doesn’t pick up a pebble for anything else.”
Dorothy M Fragaszy, an emerita professor of psychology at the University of Georgia who has published widely on animal behaviour but was unacquainted with Bruce’s exploits, praised the study as a model of how to study tool use in animals.
“The careful analyses of the behaviour in this report allow strong conclusions that the behaviour is flexible, deliberate and an independent discovery by this individual,” she said.
None of the other kea in his environment used pebbles for preening, and when other birds did manipulate stones, they picked pebbles of random sizes. Bruce’s intentions were clear.
“Bruce didn’t see anyone do this,” Bastos said. “He just came up with it by himself, which is pretty cool. We were lucky enough to observe this. We can learn a lot if we pay a little more attention to what animals are doing, both in the wild and in captivity.”
©The New York Times Company