Wild parrots name their chicks by teaching them an individual sound to identify them, researchers have found.
Humans and dolphins create unique sounds by which individuals are identified and there was some evidence to suggest captive parrots created ‘contact calls’ – special calls used to identify family and friends. But until now, it was not clear how or if this naming process worked in nature.
To test whether contact calls were innate or learned from parents, researchers from Cornell University and the University of California in the U.S. took eggs from the nests of wild green-rumped parrotlets (Forpus passerinus) and swapped them with eggs from other wild wild green-rumped parrotlet nests. Twelve nests were used in the swapping experiment.
Eight additional nests served as controls, where the eggs were removed but then put back without swapping.
By observing the chicks’ development through video and audio rigs, the scientists saw that the young parrots used the contact calls of their adoptive parents.
This suggests that the names used to identify them were learned, rather than hard-wired by DNA from their biological parents, the authors said.
“Our results provide the first experimental evidence for learned vocal production by naive parrots in nature. Nestling contact calls were more similar to the contact calls of their primary care-givers than to adults at other nests, despite half of the nestlings being raised by foster parents,” the authors wrote in their paper, which was published by the journal Proceedings of The Royal Society B.