From bird brains to polly-maths: Cockatoos learn to make tools
Parrots have proved they are clever as well as pretty after using their creative bird-brains to make tools from unfamiliar materials.
The Goffin's cockatoo, a native of Indonesia, is not known to use tools in the wild or to have evolved the ability to build nests from twigs.
Yet four captive birds demonstrated a striking level of lateral thinking by constructing tools to retrieve food placed out of their reach.
The hand-raised parrots, Figaro, Dolittle, Kiwi and Pipin, had to fashion a tool at least 6cm long that could be poked through a hole to dislodge a tasty piece of cashew nut.
Success would be rewarded by the nut being knocked off its platform and sliding down a ramp to appear through an opening.
Four materials that had to manipulated in different ways were offered to the birds. Only one, a block of larch wood, was familiar to them. The others were leafy beech twigs, cardboard and a lump of natural beeswax.
Astonished researchers watched as the parrots tore off splinters of larch wood, trimmed twigs, and cut out appropriately sized pieces of cardboard which they used to obtain the food.
The only material none of them had any luck with was the beeswax.
Dr Alice Auersperg, who led the team at the University of Veterinary Medicine in Vienna, said: "To us, the tools made from cardboard were the most interesting ones, as this material was not pre-structured and required the birds to shape their tools more actively.
"They succeeded by placing a large number of parallel bite marks along the edge of the material like a hole punch, using their curved upper beak to cut the elongated piece out of the cardboard block after reaching a certain length.
"Interestingly, this length was usually just above or very close to the minimum length required to reach the food reward placed behind the barrier."
Figaro had earlier inspired the scientists by spontaneously biting splinters from the wooden beams of his cage to manufacture tools. He used these to rake up pieces of inaccessible food.
All four parrots created twig tools. Three, including Figaro, worked out the splinter trick and two mastered the cardboard.
The findings appear in the Royal Society journal Biology Letters.
Tool manufacture was once regarded as a defining feature of being human but has been observed in chimps and other primates as well as birds including crows, vultures and Galapagos finches.
Study co-author Professor Alex Kacelnik, from Oxford University's Department of Zoology, said: "Ultimately, we want to understand how animals think - namely, to produce the equivalent of explicit computer programs capable of doing what the birds do.
"We really don't know if the birds can picture in their minds an object that doesn't yet exist and follow this image as a template to build something new, or how their brains elicit the appropriate set of movements to organise their response to novel problems, but this is what we are trying to find out.
"Studying tool-making in species like the Goffin's cockatoo, which does not make tools naturally, is especially revealing, as these birds cannot do it by following pre-programmed instructions evolved to solve this specific problem.
"These cockatoos, like other parrots, offer wonderful research opportunities: their intelligence is flexible and powerful, they can solve physical and logical problems, they can learn from watching the behaviour of others, they can learn about the surrounding objects by playing - and now it seems plausible that they can imagine which object would allow them to solve a new problem and go on to build it. I am sure that they will keep surprising us."