Tool use is a relatively rare phenomenon in nonhuman species. Direct tool sharing is even rarer.
And now, thanks to psychological researchers at the University of York and the University of St. Andrews, the short list of nonhuman tool users now includes a feathered contingent. The study has documented evidence of tool use in parrots.
The researchers observed ten captive greater vasa parrots, an African species native to Madagascar and the Comoro Islands, for eight months (from March to October). During that time, they documented various instances of tool use and tool sharing in five out of the ten birds.
The focus of the birds' attention was the calcium-rich cockle shells used as the bedding in their aviary. Researchers observed the parrots using pebbles and date pits to crush and grind the shells into small, ingestible chunks. The birds used various tactics to break down the shells. The researchers observed them using pebbles and date pits as both grinding tools inside the shells, and as wedges, which they used to break the shells apart.
These findings are the first evidence of tool use in greater vasa parrots. They are also the first evidence of a nonhuman species using tools for grinding. And finally, they are among few documented cases of direct tool sharing in a nonhuman species.
Calcium is crucial for egg-laying, so researchers were puzzled at first to find that the male parrots showed more interest in the shells than the females did. The birds' interest in the shells was most pronounced in the period just prior to breeding season. Observation later revealed that the males frequently regurgitated the shells and fed them to females shortly before mating. This behavior is believed to provide much-needed calcium to the females.
According to the study's lead author, University of York Ph.D. student Megan Lambert, any number of factors could explain this tool use in parrots. The ingenuity could be a natural inclination specific to the species, the shared result of social learning in the population, or simply a result of trial and error in individual birds. It is unknown if the greater vasa parrot uses tools in the wild. However, Lambert says the findings from the study have made the greater vasa parrot a good candidate for use in more research into physical cognition.
Want to learn more about these feathered Einsteins? Read more about vasas here.