Kea are smarter and more playful than previously thought, research shows
Kea have long been known for being equal parts lovable and obnoxious, but recent research shows their inner workings are more complex than previously thought.
The alpine parrot is notorious for its curiosity, reflected in its tendency to pester people, vandalise cars and steal from tourists.
But researchers studying kea have discovered an unexpected inner complexity, unlike any other bird species.
New research shows that kea, unlike any other known bird species, have something similar to an infectious laugh.
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They have a specific shriek which triggers them to play, a trait previously seen only in mammals.
When researchers played the shriek to wild kea, it prompted them to play with others. Even when a kea was alone, the sound caused them to play by themselves, doing aerial acrobatics.
The findings were reported in Current Biology on Monday.
"The fact that at least some of these birds started playing spontaneously when no other birds had been playing suggests that, similar to human laughter, it had an emotional effect on the birds that heard it, putting them in a playful state," said researcher Raoul Schwing, of the Messerli Research Institute in Austria.
When kea heard the sound, they did not join already playing birds; they instead started playing with others that were not already playing.
It meant kea were not being invited to play, but that the sound triggered an inherent sense of playfulness, the researchers said.
Such an example of "emotionally contagious vocalisation" had never been seen before in a bird, previously only observed in chimpanzees and rats.
Last month, research published in the PLOS One journal made another discovery about kea: they're excellent at teamwork.
Kea at Christchurch's Willowbank Wildlife Reserve passed a series of intelligence tests with flying colours, showing an ability to co-operate similar to chimpanzees and elephants.
In the experiment, two kea were separated on either side of a chicken wire fence. The birds had to tug on a string in unison to drag a board with food towards them.
If only one string was pulled, the food would move out of reach. To get the food, they had to pull the string together.
The results showed the kea were willing to wait up to a minute for the other bird to arrive before pulling the string, even distracting themselves while waiting.
"This is the first demonstration that any non-human animal can wait for over a minute for a cooperative partner, and the first conclusive evidence that any bird species can successful track when a cooperative partner is required and when not," the researchers found.
A study published last week from the same research showed kea did not mind if they were given unequal rewards.
Unlike many mammals, such as humans and chimpanzees, they did not appear to have an innate sense of fairness, and were willing to work together even if their partner got a better reward than they did.
Researchers say better understanding of kea can help with their conservation.
Kea are undergoing a sharp population decline, due largely to human encroachment into their habitat.