Source: Radio New Zealand
Bruce the disabled kea has achieved social dominance with an innovative fighting technique. Supplied / Ximena Nelson
A disabled kea has achieved social dominance with an innovative fighting technique.
Though he lacks the top half of his beak, Bruce keeps a stiff upper lip.
Using his lower mandible as a spear, Bruce has never lost a fight and has secured his spot as the top bird at Willowbank Wildlife Reserve in Christchurch.
The kea was found injured in 2013, and has lived at the reserve ever since.
But despite his injury, or even because of it, Bruce has found an advantage.
“A way kea displace other kea is by biting them. Of course, Bruce can’t bite because he doesn’t have the upper mandible, so what he does is he essentially stretches out his neck and jabs with his lower beak kind of like a spear,” behavioural ecologist Ximena Nelson said.
“He will often twist his neck a little bit, and he targets different body parts than the other kea. You can really see that it’s very effective because the other will spring away when he does this.”
Bruce uses his lower mandible as a spear. Supplied / Dr Alex Grabham
Professor Nelson had been studying the kea at Willowbank with students and colleagues from the University of Canterbury.
When ranking the birds’ hierarchy, the researchers were surprised to see Bruce at the very top.
Nelson said Bruce’s signature move was so effective that the other birds were scared to challenge him.
“Bruce was so dominant that he actually doesn’t fight very often. We saw hundreds of fights but Bruce only fought 36 times or something, because all the birds would part like the red sea when he was around,” she laughed.
Bruce had been enjoying the perks of his position as best in the nest, with first dibs at dinner time.
“He completely dominates the feeding platform. There are four central feeding trays in the aviary at Willowbank, and the other birds just totally let him go to each feeding tray and he picks his own favourite foods without any interruption from the other birds,” she said.
“The other birds just watch from the side, and once he’s done with the four trays, then the other birds come along.”
Bruce the kea. Supplied / Ximena Nelson
Bruce was also the only male kea to be preened by the other males, and had the lowest level of stress chemicals in his poo thanks to the lack of challengers for his position.
But Nelson said Bruce had his fair share of challenges, eating highest among them.
Over the years he had found ways to chow down, but Bruce still had the lowest weight in his group.
“He uses his tongue essentially as sort of a top mandible, or he will press food against a rock and smush it up that way,” she explained.
“He’s got lots of behavioural innovations that he uses to compensate for the lack of his beak.”
Bruce compensates for the lack of his beak. Supplied / Ximena Nelson
Staff at the reserve suspected Bruce’s injury was caused by a trap.
Dr Laura Young, a field researcher at the Kea Conservation Trust, said traps remained a threat to native birds – but the situation had improved significantly in the years since Bruce was injured in 2013.
“In the past, many kea and other ground-dwelling birds, kiwi, weka, and so on, have been killed by traps of various types,” she said.
“Luckily now there’s been recognition of this and there’s better standards in place, there’s been banning of particular trap types in kea habitat as well, so we’re on the right track.”
Bruce has never lost a fight. Supplied / Dr Alex Grabham
Professor Nelson said Bruce’s rise to fame showed how adaptable some animals could be.
“Maybe animals, particularly animals that are fairly smart, they will actually be able to compensate for their disability and, in this case, compensate so well that they’re actually clearly dominant.
“Maybe we need to really look at the behaviour of animals before we decide about whether or not we need an intervention, because actually maybe the animal would be better off without it.”
Dr Young said the research was good news for conservationists, who were often left wondering if the animals they released could make it on their own.
“What’s really encouraging about the Willowbank study is to see that other birds can help out an injured bird,” she said.
“If the same applies to wild birds which I think it does, then that’s really encouraging because it means once they get released after their injury they will have help because they’re a social species.”
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– Published by EveningReport.nz and AsiaPacificReport.nz, see: MIL OSI in partnership with Radio New Zealand
