Scientists have long known that kea are intelligent, but new research shows they're even smarter than previously thought.
According to new research, the birds are capable of reasoning about probability, giving them the ability to make educated guesses - a level of intelligence previously only known in primates and humans.
Auckland University PhD student Amalia Bastos says it's a world-first discovery.
"It's the first evidence that birds have something called domain general intelligence, which suggests that they can integrate, they can combine information of different types to make a single judgment," Bastos told Newshub.
Bastos, along with Auckland University associate professor Alex Taylor, carried out a study on six kea from Willowbank Wildlife Reserve in Christchurch to test their ability to make predictions using statistical, physical and social information in a way similar to how a human would.
The birds were first shown that when given the choice between picking a black token and an orange token, if they chose the black one they would get a food reward while if they chose the orange one they would get nothing.
The researchers then brought out two mixed jars of tokens in front of the birds, one with more black tokens and the other with more orange ones.
They then reached into each of the jars and brought out a token hidden in their fist to see which one hand the bird would choose, even though they couldn't see the colour of the token.
According to the study, the birds "consistently chose the hand that had reached into the jar with the greatest number of black tokens, showing they could use the relative frequency of black and orange tokens to make a prediction".
The researchers also did a similar test to conclude that the kea could "combine information about the physical world with information about the relative frequency of tokens - an ability that has so far only been demonstrated in human infants".
A final test showed the birds could also factor social information in to their decisions.
When confronted with a choice offered by two different researchers - one who always took a black token even though there were more orange tokens in the jar they were pulling them from and one who took a token without looking, but from a jar with more black tokens than orange and so also ended up with black tokens - the birds opted for the fist shown by the biased person.
"The results from the study are surprising as they mirror those from infants and chimpanzees in similar tests," said Bastos.
"They show kea can look at the ratio of objects to make a prediction about uncertain events – what we call statistical inference. That kea could then integrate different types of information into these predictions was really unexpected: this type of integration has been thought to require language. This is the first evidence that a bird can make true statistical inferences and integrate different types of information into their predictions of uncertain events."
Bastos told Newshub that researchers now want to give the test to other birds.
"The next step is to [test] other species of birds to see how they do on these experiments and then we can sort of trace back where along the evolutionary line this would have evolved."
Associate professor Taylor said the study might also help researchers learn more about artificial intelligence (AI).
"One of the holy grails of research on artificial intelligence is the type of common-sense reasoning that humans show, where we bring together multiple sources of information into a single prediction or judgement about what will happen next in the world," he said.
"Our work suggests that aspects of this ability have likely evolved twice on our planet, in primates and birds. This suggests that, for AI researchers looking to biological intelligence for inspiration, it might be useful to complement the current focus on the mammalian brain with work on the very different avian brain as well."