Australian magpies can understand what other birds are saying to each other, a new study has found.
The research, published in the journal Animal Behaviour, says the wily magpie has learned the meanings of different noisy miner calls and essentially eavesdrops to find out which predators are near.
Noisy miners – a small, native honeyeater – have different warning calls for ground-based and aerial predators. By playing both kinds of recording to a series of wild magpies, researchers observed the magpies raising their beaks to the sky, or dropping their heads to the ground.
The study took place between February and April 2016 in four locations in Canberra, including the Australian National University campus and parks in Turner.
Researchers lured the magpies with grated cheese, then played the noisy miner calls, videotaping the results.
As a control, they also rolled a large orange ball towards the magpies to see how they ordinarily tilted their beaks to ground threats, and threw the ball to see how they reacted to aerial threats.
Overall 30 wild adult magpies had their reactions recorded – twice – with nine flying away.
The researchers recorded an average maximum beak angle of 29 degrees for the thrown ball, and an average maximum of nine degrees when it was rolled.
The miners’ aerial warning prompted an average maximum beak angle of 31 degrees, and the ground warning prompted an average maximum of 24.
One of the study’s authors, Dominique Potvin, said the magpies demonstrated an astonishing level of insight.
“A lot of birds around the world have been shown to respond to a degree of threat, but this is a little bit more nuanced. We’re not looking at ‘if you scream louder does that mean more danger and you hide’. This is a very particular sound that indicates the spatial location of something. For the magpies to actually hone in on that is pretty new.”
Magpies and miners broadly face the same types of predators – brown goshawks, peregrine falcons and boobook owls in the air, and foxes, cats, dogs and snakes on the ground – and the two frequently live in the same ecosystem.
Potvin said this had spurred the magpies’ learned behaviour.
“Magpies are generally found on the ground and noisy miners are generally found up in trees. It pays for the magpie to pay attention to somebody who has a better view of predators than they do.”
She said it was unclear whether other birds could do the same, but it was highly likely other magpies around Australia already did.
“Magpies are a pretty smart group. We’re not sure if they’re learning this from other magpies or if they’re figuring it out on their own, but the ability is there. We don’t think this would be isolated to Canberra populations.”
As part of the experiment, researchers also played a third call: a generic, non-warning call from a crimson rosella. They found the magpies did not respond.
Potvin said the findings opened up new avenues for animal cognition research. “It’s a good piece of the puzzle,” she said. “Looking at the social relationships between species that live in communities.”