Rooks are a lot brighter than they appear in the wild and have an uncanny ability to use tools, a study has shown.
The birds, members of the crow family, have astounded scientists by proving to be as good with their beaks as chimpanzees are with their hands.
Given a series of tasks, not only did they select the right tools for the job, but showed they could modify tools and use them in sequence.
In one test rooks had to choose the right-sized stones to drop down tubes of different diameter. When a stone fitted the tube it tipped up a platform that released a food reward.
Video clips of the birds showed them ignoring the wrong stones and carefully picking out the correct ones.
The birds were also capable of modifying sticks to fetch food, and when the correct tool was out of reach, they used another tool to retrieve it. They were even able to bend a straight piece of wire into a hook with which to winkle out food from a tube.
Their antics were especially impressive because rooks have never been known to use tools in the wild – unlike New Caledonian crows, which are famed for their tool dexterity. Scientists believe they display a high degree of innate intelligence, rather than merely the ability to adapt to an environment.
Dr Nathan Emery, from Queen Mary, University of London, in whose laboratory the experiments were carried out, said: “We suggest that this is the first unambiguous evidence of animal insight, because the rooks made a hook tool on their first trial, and we know that they had no previous experience of making hook tools from wire because the birds were all hand-raised.”
The research appears online in the journal Proceedings of the National Academy of Sciences.
– (PA)