Saturday, May 7, 2011

Brainy Birds Use Tools in Different Ways

This is the parrot Kea using a ball shaped tool at the Multi Access Box. (Alice Auersperg). Photo courtesy: The Epoch Times

Scientists have been testing the problem-solving skills of members of two of the smartest bird families - crows and parrots - with fascinating results.

Researchers at the University of Vienna in conjunction with the University of Oxford studied the New Caledonian crow, and the kea, a New Zealand parrot.

The New Caledonian crow, found in islands in the southwest Pacific, makes tools out of sticks and leaves in nature when exploring the forest.

"It shows great innovative skills when it comes to technical problems involving tool use," says study author Ludwig Huber, head of the Department of Cognitive Biology in Vienna, in a press release.

Kea, though not having been documented as using tools in the wild, are likewise known for their intelligence.

The team set up a box with transparent walls around a food reward on a platform, with a different mechanism in each wall to enable the bird to obtain the reward.

"The animals could choose between pulling a string which was tied around the reward, pulling a hook-shaped lever to open a window, inserting a marble (compact tool) into a curved ball-path leading towards the reward or inserting a rod-shaped stick-tool into an opening and maneuver[ing] it over a gap towards the food in order to push the reward off its platform," explains lead author Alice Auersperg in the release.

The New Caledonian crow Uek uses the window entrance at the Multi Access Box. (Alice Auersperg). Photo courtesy: The Epoch Times

Each bird was left to choose a solution to obtain the food. After the bird had used the mechanism a certain number of times, the investigators blocked it, forcing the bird to choose another.

"This way we could observe not only the differences in the order of solutions that the animals established but also how quickly they were able to switch," says co-author Gyula Gajdon at the University of Vienna in the release.

Of the six kea and five New Caledonian crows studied, only one individual of each species managed to successfully execute all four mechanisms.

The kea faced the biggest challenge with the stick-tool, which the authors reasoned is difficult to manipulate with a curved beak.

"It is therefore all the more impressive that Kermit [the one kea that had managed all four mechanisms] succeeded to overcome this handicap. The strategy he used gives the strong impression that he acted in a goal directed manner," says Huber.

The crow's most difficult task was opening the window with a lever, since in the wild they tend to examine unknown objects by pecking with their beaks or poking with sticks, rather than pulling them.

"After Uek [the one crow that had accomplished all four solutions] succeeded to open the window, she would not stick her head through the entrance to directly reach for the food like the kea did but instead used the stick to poke it off its platform," says Auersperg.

In the second study, the scientists let the kea observe Kermit use a stick to reach a food reward through a wall. Three birds then used the stick-tool successfully.

"This is to our knowledge the first evidence of a bird species, lacking a socio-ecological predisposition for using stick-like objects, designating the direction of a stick-tool as a functional extension of a body part (beak)," the authors wrote.

The following video contains parts of the experiments:

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