Meet Bruce, the disabled kea who practices ‘self care’
Each day, Bruce goes on the hunt for the perfect pebble. This is because Bruce is a little bit different from other keas.
Bruce lost his upper beak in the wild and has been in the care of zookeepers at the Willowbank Wildlife Reserve in Christchurch since he was a juvenile.
While the zookeepers ensure that Bruce has access to soft foods that make it easy for him to eat without his upper beak, there’s one thing that Bruce was having difficulty with. Preening.
Preening is critical to a bird’s life. It keeps them clean, able to fly and attract a mate. But without an upper beak, it’s almost impossible. What Bruce did to compensate for his disability has shocked scientists.
In 2019, zookeepers began to notice Bruce was spending a lot of time playing around with pebbles. Exactly why, they didn’t know. After closely observing the behaviour they soon realised he was using the pebble to preen himself.
According to Kea expert Amalia Bastos, the process goes like this:
“Bruce usually starts off by looking around the aviary floor for an appropriate pebble. He puts his beak very close to the ground so he can investigate the pebbles up close.
“Once he finds a suitable pebble, he picks it up and rolls it around with his tongue for quite some time. We’re not sure if he does this to clean the pebble, or if he is assessing the size or shape of the pebble as a tool. Sometimes he will spit it out at this stage and substitute it for another pebble.
“After selecting a pebble of his preference, he will carry it elsewhere, for example onto the top of a rock or a tree branch, and begin preening with it. In most cases this involves holding the pebble under his tongue and scraping his feathers between his lower bill and the pebble. This is likely a way to remove dirt and ectoparasites from his feathers, like other birds can do by scraping their feathers between their upper and lower bills.”
This is the first evidence of tool use for self care by a kea. The groundbreaking findings have been published today in the journal Scientific Reports.
What’s most fascinating for scientists like Amalia is that Bruce couldn’t have learned the behaviour from another bird. Rather, he was innovating.
“It really goes to show how flexibly kea can deal with problems in their lives and in their environments, coming up with clever solutions when they are needed,” Amalia says.
A critical part of the study was establishing that the tool use was intentional rather than incidental. After many hours of observing Bruce, the scientists found that 90 per cent of the time when he picked up a pebble he used it to preen. In addition to this, 95 per cent of instances where he was preening with a pebble but dropped it, he immediately retrieved the pebble or replaced it.
“This indicates that he really did mean to hold a pebble in his beak while preening, again suggesting this is intentional,” Amalia says. “He also selected specific pebbles of a particular size, which differed in size from both a random sample of pebbles and stones in the aviary, and the objects other kea in his aviary interacted with during that time.”
Kea, a parrot endemic to New Zealand, are known to be among the world’s most intelligent birds. Just last year, another paper published in Nature (also authored by Amalia) demonstrated that keas are capable of predicting the future by balancing the probabilities, which was previously thought to be unique to humans and apes.
Amalia says that tool use doesn’t play a big role for keas in the wild. The only other record of wild keas using tools is from a population in Fiordland, in the south-western corner of New Zealand’s South Island, that had learnt to use sticks to set off the traps intended for invasive species and then grab the bait.
Following this most recent study, Amalia is now interested in understanding what kind of pebbles Bruce is most attracted to. “We don’t have answers for this just yet but it would tell us which properties kea might attend to when they interact with objects in their environment.
“The hope is that, by showing just how clever these endangered birds are, more people will be compelled to help preserve them in the wild. Some of this research also has direct applications for their conservation as well.”