A parrot species has surprised scientists by making and sharing tools to grind seashells into powder as a way to get calcium they can consume as a nutritional supplement.
Ten captive black-feathered greater vasa parrots, natives of Madagascar, were filmed by researchers in the United Kingdom, who recorded a number of them using pebbles or dried date pits to grind cockle shells into powder.
The behavior, initiated completely by the birds on their own, represents the first time a nonhuman species has been observed making tools for grinding, the researchers report in the journal Biology Letters.
It is also one of the few times a species has been observed sharing tools directly, they say.
"The use of tools by nonhuman animals remains an exceedingly rare phenomenon," says study lead author Megan Lambert of the University of York. "These observations provide new insights into the tool-using capabilities of parrots and give rise to further questions as to why this species uses tools."
The birds seemed to show the greatest interest in grinding shells for calcium during their mating season, suggesting they need to increase their calcium intake in preparation for egg-laying.
"Unlike mammals, birds cannot efficiently store calcium in the skeleton and so may still require an extra boost during the breeding season to assist with the formation of their eggshells, which are made almost entirely of calcium," Lambert explains.
Greater vasa parrots, Coracopsis vasa, have long been seen as intelligent creatures and have often been observed in captivity playing with objects.
In the world's more than 300 species, they are among only a small number known to use tools, along with hyacinth macaws, which will utilize small sticks to wedge open nuts, and black palm cockatoos, which will drum on trees with rocks as attention-getting behavior during social displays.
Whether the tool use seen in the parrots is instinctive or perhaps a learned behavior is unclear, the researchers say.
"Tool use could reflect an innate predisposition in the parrots, or it could be the result of individual trial and error learning or some form of social learning," Lambert suggests.
Since the study only looked at captive parrots, the question of whether the behavior occurs in the wild remains to be answered, she says.
However, she says, the study findings definitely "highlight the greater vasa parrot as a species of interest for further studies of physical cognition."
