- by John Timmer - Nov 7 2012, 4:00am IST
Tool use was once thought to be one of the defining features of humans, but examples of tool use were eventually observed in primates and other mammals. But the biggest surprise came when birds were observing tools in the wild. After all, birds are the only surviving dinosaurs, and mammals and dinosaurs hadn't shared a common ancestor for hundreds of millions of years. In the wild, tool use has been limited to the corvids (crows and jays), which show a variety of other complex behaviors—they'll remember your face and recognize the passing of their dead.
Parrots, in contrast, have mostly been noted for their linguistic skills, and there has only been very limited evidence that they use anything resembling a tool in the wild (primarily, they seem to use external objects to position nuts while feeding). But a captive cockatoo has now been observed using multiple steps to process a tool, behavior that appears to be completely spontaneous. And it hasnever been seen in this species in the wild.
The bird in question is Figaro, a male Goffin’s cockatoo. The species is native to a group of islands in Indonesia, but Figaro has been living outside of Vienna, where he's watched over by members of the local university's Department of Cognitive Biology. Contrary to what you might expect, Figaro wasn't undergoing any sort of elaborate testing routine when his toolmaking abilities emerged. Instead, he was playing with a stone. And, apparently, Figaro was a bit clumsy with his toy, as he dropped it behind a metal divider.
After failing to retrieve it with his claw, however, the researchers were surprised to see Figaro fly off, retrieve a piece of bamboo, and use that to try to push the stone back where he could access it. The attempt failed, but the researchers were intrigued enough that they gave the cockatoo a bit of added incentive by placing a nut on the other side of the metal screen.
Figaro initially picked up a stick from the enclosure's floor, but this proved to be too short to reach the food. So, he actually splintered off a piece of the enclosure's wooden base, and successfully used that to pull the nut towards the wire until he could use his beak to grab it.
Figaro used a different tool in each subsequent trial, and in most cases made some modifications to it before successfully retrieving a nut. In at least one case, he performed four separate modifications before putting a stick to use in retrieving the nut. He also managed to use the tool in two different ways, often alternating dragging and sweeping motions in his efforts to pull the food within reach.
After observing this, the authors used the same setup to test another male cockatoo, but he showed no indications of tool use. But a female who witnessed Figaro in action (she was in the cage "to avoid the stress of isolation") showed the impressive abilities of birds to absorb social information. Heidi, the bird in question, attempted to insert sticks into the enclosure, as she had seen Figaro do. She did not, however, adjust their sizes or attempt to manipulate them once they were on the same side of the wire mesh as the nut. Perhaps if she had been given more time to observe Figaro at work (he chased her off), she might have had a greater sense of how to use the sticks.
The authors conclude that tool use is within the cognitive capacity of this species, even though they have never been observed using tools in the wild. They're not sure why Figaro had the breakthrough that he did, but it's clear that the behavior, once learned, was sticking around.
The authors note the corvids and parrots are so widely separated within the birds' evolutionary tree that it's unlikely that they had a common, tool-using ancestor. They argue that, although we tend to think of tool use as a distinctive mental capacity, it might be more accurate to consider it as a possible outcome of having some minimum level of what they call "physical intelligence." Goffin’s cockatoos don't normally exercise this capacity but, under the right circumstances, it can be uncovered.
The paper doesn't suggest what their next planned steps are. But I'm intrigued by the possibility that they might allow other members of their flocks to watch Figaro in action. It would provide both an interesting test of birds' ability to engage in social learning. And it could provide a better idea of whether all Goffin’s cockatoos have the same physical intelligence demonstrated by Figaro.