Bruce the very clever kea only has half a beak, so he worked out how to use pebbles to preen himself

Friday, 10 September 2021

Bruce the kea has lost the top half of his beak. Undaunted, he has worked out how to use pebbles to preen himself. It's thought to be the first time a kea has been observed using a tool in this way.

Bruce the kea is a very clever boy.

After losing the upper part of his beak at a young age, he has worked out how to use pebbles to preen himself.

Such tool use is rare in the wild, and it is thought to be the first time it’s been seen in a kea.

Bruce the kea was found as a young bird with the top half of his beak missing

“To have an individual innovate tool use in response to his disability shows great flexibility in their intelligence. They’re able to adapt and flexibly solve new problems as they emerge,” researcher Amalia Bastos, a PhD candidate for the University of Auckland School of Psychology, said.

Once Bruce the kea finds the right stone, he holds it against his lower bill with his tongue while preening.

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It's the first reported case of a kea innovating tool use for preening

Bruce can also manipulate large objects by hooking them under his tongue.

A researcher at Arthur’s Pass found Bruce as a juvenile in 2013 with the upper half of his beak missing. It’s not known exactly how the kea was injured, but it’s thought to be the result of an accident with a pest trap.

Bruce was taken to the South Island Wildlife Hospital, where he was nursed back to health and now lives in a large aviary at Willowbank Wildlife Reserve in Christchurch.

Although keepers ensure that Bruce had access to soft foods which can be eaten without an upper bill, he also learned to eat harder foods by pressing them up against hard objects..

Bruce could manipulate various objects by holding them between his tongue and lower mandible. His innovative pebble preening behaviour was first noted by keepers at Willowbank in late 2019.

Researchers observed Bruce in the aviary at Willowbank for nine days, and saw him manipulating objects or preening himself. They established five lines of evidence to show his tool use was intentional.

In more than 90 per cent of instances where Bruce picked up a pebble, he then went on to use it to help preen.

Secondly, in 95 per cent of instances where Bruce dropped a pebble, he retrieved or replaced it before continuing to preen.

Third, Bruce selected pebbles of a specific size that were suitable for preening, rather than randomly sampling pebbles.

None of the other 12 kea in the aviary used pebbles while preening, and when they did interact with objects they selected stones of different sizes to those Bruce used.

Bastos said Bruce’s behaviour was consistent and repeated, and so was regarded as intentional and innovative.

“The pebbles he picked up were different to those picked up by other kea, they were always of a certain size. This points to an intentional act: to find a way to preen himself without the top half of his beak,” Bastos said.

A study reporting on Bruce’s special talents has been published in the journal Scientific Reports.