Many animals are known to use tools, but a disabled parrot named Bruce may be one of the most inventive nonhuman tool inventors of all time: he has designed and uses his own prosthetic beak.
Bruce is a kea, a New Zealand-only parrot species. He’s about 9 years old, and when wildlife researchers discovered him as a baby, he was missing his upper beak, which had been caught in a trap designed to catch rats and other invasive mammals that the country was attempting to eradicate. This is a severe disability because kea use their dramatically long and curved upper beaks to preen their feathers in order to rid them of parasites and dirt and grime.
Bruce, on the other hand, has devised a solution: he has taught himself to pick up pebbles of the appropriate size, place them between his tongue and lower beak, and comb through his plumage with the tip of the stone. Other animals make use of tools, but Bruce’s invention of his own prosthetic is one-of-a-kind.
The findings were published in the journal Scientific Reports on Friday. Animal behaviour research is difficult because researchers must make careful, objective observations while also being wary of bias caused by anthropomorphizing, or incorrectly attributing human characteristics to animals.
“The main criticism we received before publication was, ‘Well, this activity with the pebbles may have just been accidental — you saw him when coincidentally he had a pebble in his mouth,’” said Amalia P.M. Bastos, the study’s lead author and an animal cognition researcher at the University of Auckland. “However, no. This was done several times. He drops the pebble and then goes to pick it up. He’s after that pebble. He doesn’t pick up a pebble for anything else unless he’s preening.”
Dorothy M. Fragaszy, an emerita professor of psychology at the University of Georgia who has published extensively on animal behaviour but was unaware of Bruce’s exploits, lauded the study as a model for studying tool use in animals.
“The careful analyses of the behaviour in this report allow strong conclusions that the behaviour is flexible, deliberate, and the result of this individual’s independent discovery,” she said.
The researchers established strict guidelines for themselves.
First, they established that Bruce was not randomly playing with pebbles: nine times out of ten, when he picked up a pebble, he used it for preening. When he dropped a pebble, he either retrieved it or picked up another one before continuing to preen. Rather than sampling pebbles at random, he consistently picked up pebbles of the same size.
None of the other kea in his environment used pebbles for preening, and when other birds did use stones for preening, they chose pebbles of varying sizes. Bruce’s intentions were crystal clear.
Ms. Bastos stated, “Bruce didn’t see anyone do this.” “He came up with it on his own, which is pretty cool. We were fortunate enough to witness this. If we pay more attention to what animals do, both in the wild and in captivity, we can learn a lot.”
Keas in general are quite intelligent, but Ms. Bastos stated that Bruce was clearly smarter than other birds, being able to be trained in fairly complex tasks while also developing his own ideas. Ms. Bastos stated that she was occasionally asked why she did not provide Bruce with a prosthetic beak.
She always responds, “He doesn’t need one.” “He’s content with his own.”