Four Pinyon jay visiting a garden feeder

Pinyon jays, which live in Mexico and the western United States, and search for food in flocks, gather at a bird feeder. Credit: Mike Read/NPL

Zoology

Jays play nicely with the right hormone

A molecule boosts generosity in birds but doesn’t make them altruistic.

Birds share more readily after being given the avian equivalent of oxytocin, a hormone linked with social bonding and maternal behaviour in mammals.

The hormone mesotocin boosts gregariousness in birds. To see what other powers it might have, Juan Duque and his colleagues at the University of Nebraska–Lincoln trained caged pinyon jays (Gymnorhinus cyanocephalus) to choose between sending a gift of a mealworm to a nearby jay or sending the treat to an empty cage.

When guaranteed a treat themselves, jays dosed with mesotocin rewarded their neighbours in nearly 32% of trials, whereas birds receiving no hormone rewarded others only 8% of the time. But the team found that the birds were not selfless — jays that were offered no treat themselves did not altruistically reward their neighbours.

The experiments bolster the evidence that mesotocin influences social behaviour in birds, just as oxytocin does in mammals.