The use of tools among animals is seen as a measure of intelligence. Chimps and crows are known to be prolific tools users, but outside of these groups, tool use is not particularly common. Now, a species of parrot from Madagascar has been filmed using tools to grind objects, a behavior that until now was thought to be uniquely human. Not only that, but they were also observed sharing the tools among themselves, specifically male to female, a behavior rarely seen in nonhuman animals.
While tool use is common among crows, ravens and their relatives (such as crafting hooks to get food), the behavior among the 300 species of parrots is a rarer event, although there have been a few documented cases. In the wild, hyacinth macaws use chewed up leaves and sticks to prevent nuts from slipping as they open them, and keas in captivity have been shown to use sticks to retrieve food that is just out of reach. Now, the greater vasa parrot (Coracopsis vasa) can be added to this select group of innovative psittacines.
The birds in question are natives of the island of Madagascar off the south-east coast of Africa. Not resplendent in bright greens and reds as you might expect a parrot to be, the greater vasa are more muted in grays and blacks. The birds also form an unusual mating system where multiple males have exclusive sexual relationships with multiple females and do not mate outside this group. Now that it’s found they can use tools, it appears the parrots are even more remarkable than previously thought.
The researchers, from the universities of York and St. Andrews, watched a group of 10 parrots in captivity, and filmed them over a period of eight months. They found that five of the birds frequently placed stones and date pits on the inside of cockle shells littering the floor of their enclosure. They then ground the stone or pit against the shell and licked off the powder produced. They also used the objects to snap off smaller parts of the shells that they also ate.
Many birds and some reptiles will consume shells and bones in order to get enough calcium so that the females can produce eggshells, as they can’t store it in their bones. This is probably what is behind the behavior observed in the parrots, as the researchers observed that tool use increased just before breeding season. And yet to confuse things even more, it wasn’t actually the females who were doing most of the grinding, it was the males. As males are prone to feeding the females before, during, and after mating, it’s suspected that the males might be passing on the extra calcium to the females, possibly as a show of their health.
“The use of tools by nonhuman animals remains an exceedingly rare phenomenon,” explains Megan Lambert, who led the study published in Biology Letters, in a statement. “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 researchers now hope to observe the birds in the wild to see if the behavior is driven by their environment in captivity, or if the parrots are born with the ability to use tools.