African grey parrot, named Lizzy, at Loro Parque in Tenerife, Spain.

African grey parrots bestow favours on others of their species— even those that can’t reciprocate. Credit: Anette Mertens

Animal behaviour

Parrots give each other gifts without promise of reward

African grey parrots show a type of insightful generosity recorded in only humans, orangutans and a few other species.

Humans and some other apes are known for helping unrelated members of their own species. Now, the first non-mammal, the African grey parrot (Psittacus erithacus), joins the ranks of animals that provide help after gauging the beneficiary’s needs.

Désirée Brucks and Auguste von Bayern at the Max Planck Institute for Ornithology in Seewiesen, Germany, trained zoo parrots in an enclosure to pass tokens through an ‘exchange hole’ to a researcher, who then handed over walnuts, a beloved snack. The scientists next placed two parrots in adjacent enclosures with a ‘transfer hole’ between them. One bird had tokens, but a blocked exchange hole. The other had access to the researcher and the walnuts, but no tokens.

In the very first session, seven of eight parrots with tokens spontaneously transferred them to their partner, even though they would receive no benefit for doing so. These parrots generally didn’t bother passing over tokens when no parrot was next door, or when the other parrot couldn’t make an exchange for food, suggesting that they understood the import of their actions.

When partners switched roles, parrots that had benefited from a partner’s generosity returned the favour, hinting at their motivation for helping.