Cockatoos crack lock-picking puzzle
Cockatoos can pick their way through a series of locks to reach a reward, scientists have found.
Researchers presented 10 birds with a box containing a cashew nut treat, which they could reach by removing five different interlocking devices.
One of the Goffin's cockatoos, called "Pipin", solved the complex mechanical puzzle unassisted within two hours.
Several other birds mastered the task after observing peers or being presented with the locks incrementally.
The study, carried out by scientists from the University of Oxford in the UK, the University of Vienna in Austria and the Max Planck Institute in Germany, is published in the journal PLoS One.
To reach the nut, the captive Goffin's cockatoos (Cacatua goffini) had to remove a pin, followed by a screw, a bolt, then turn a wheel and move a latch sideways.
"The progress of the birds towards the solution is unaffected by the fact that the goal is very distant," said Professor Alex Kacelnik from the University of Oxford's department of zoology, who co-authored the study.
He added: "We cannot prove that the birds understand the physical structure of the problem as an adult human would, but we can infer from their behaviour that they are sensitive to how objects act on each other."
The results showed in most cases that once a bird had mastered how to remove a lock it could remove it again without any error.
The scientists tested the animals' cognitive skills further by mixing up the lock sequence. The devices were re-ordered, removed or disabled.
Researchers found that the birds responded to the "modified" puzzle by working on the new first step to unlock the box, rather than applying the technique they had learned before.
"That tells us they are capable of innovating new sequences without any further trial," said Prof Kacelnik, explaining what the cockatoos' actions reveal about their intelligence.
"They are not simply repeating what has been rewarded before, but they are creating new series of actions... without any practice."
Goffin's cockatoos are a species of Indonesian parrot which are known for their sociability and playful, exploratory behaviour. According to the team the animals' tendency to explore by touching objects made them good subjects for the study.
Last year, one of the captive cockatoos surprised the team by spontaneously making and using "tools" to reach food.
Despite this display, Prof Kacelnik cautioned: "We are not saying one way or another whether this species is particularly smart. That is not our message."
"It would be too easy to say that the cockatoos understand the problem, but this claim will be justified when we can reproduce the details of the animals' response to a large [range] of novel problems."