African grey parrots help other birds get food despite no benefit to themselves, a behaviour only previously seen in apes

African grey parrots help their peers complete tasks despite no immediate benefit to themselves, researchers have found, in the first study to show that birds display such apparently “selfless” behaviour.

While other prosocial behaviours have been seen in birds, the team say helping peers to achieve a goal, so-called “instrumental helping”, has only previously been shown outside of humans in orangutans and bonobos.

Dr Désirée Brucks, a co-author of the paper from Max Planck Institute for Ornithology, said it was an obvious choice to try an experiment with parrots.

“Parrots and corvids, crows and ravens, are really known for being the brightest birds around, they are often referred to as ‘feathered apes’ and they have been tested in many studies on problem solving or word learning,” she said.

However the bonhomie does not extend to all birds, or even all parrots: a previous study has shown that ravens do not help their peers complete a task, while the new research shows blue-headed macaws are also rather selfish.

The team say their findings suggest the helpful behaviour cropped up multiple times over the course of evolution.

“It seems that potentially similar social and ecological pressures on mammals and also birds lead to the development of similar behaviours,” said Brucks.

Writing in the journal Current Biology, Brucks and colleagues report how they tested two parrot species in a task that involved the birds passing a token, in the form of a metal ring, through a hole in their compartment to a neighbouring bird of the same species. This token could then be passed by the second bird to a human, via another hole, who would exchange it for a piece of walnut.

In total eight African grey parrots and six blue-headed macaws were involved in the experiments. All were trained individually to exchange the tokens for food when a human held out their hand.

The team found African grey parrots helped their neighbours by passing tokens to their neighbour when a human held out their hand, allowing the second bird to drop it through the hole and receive a tasty treat.

The same behaviour was seen when the roles of the birds were reversed. The more tokens a bird had previously given, the more they received in return.

However, the team stress the birds did not know at the outset that their favour would be reciprocated, suggesting it is something of a “selfless” act.

Far fewer tokens were passed between birds when there was no human signal and no hole for them to exchange the token – suggesting the parrots did not simply pass tokens for fun. The parrots also passed fewer tokens to the second compartment when there was no neighbour present.

When the experiments were repeated with blue-headed macaws, the birds rarely passed tokens to their neighbour.

The upshot, the team say, is that the African grey parrots were helping peers to achieve their task, adding the behaviour is more complex than simply sharing food with a neighbour since it involves understanding the needs of another bird for the latter to achieve their goal.

The team say the differences between the species may be down to African grey parrots gathering in huge flocks at night but splitting into smaller groups during the day to forage. Brucks said such behaviour is thought to require strong social cognitive abilities, adding that being helpful might help the birds gain a good reputation with their peers, making it more likely they would team up for foraging and other tasks.

By contrast, reputation might not be important to blue-headed macaws as they live in smaller, more stable flocks, possibly with a more hierarchical structure and a lower emphasis on sharing resources. Indeed in another task the team found these birds were less keen than African grey parrots on sharing a bowl of food with their peers.

Dr Manon Schweinfurth, an expert in animal behaviour from the University of St Andrews, who was not involved in the work, said evidence of reciprocal behaviour in African grey parrots is fascinating. “It has been thought that it is so cognitively demanding that only humans can show it. [But] we now get more and more evidence from other animals that they are able to show reciprocity,” she said.

Schweinfurth added that the finding that some birds, as well as some mammals, show instrumental helping might be rooted in the fact that birds feed their young.

“It is in their behavioural repertoire to hand over things to [members of the same species],” she said.