Not So Bird-Brained After All: Rooks Make and Use Tools

By Eliza Strickland | May 26, 2009 10:13 am

rooks toolFour rooks by the names of Cook, Connelly, Fry, and Monroe have upped estimates of birds’ intelligence by mastering a series of challenges in which they had to use tools to get tasty worms. Researchers say that the birds’ skills rivalled those of well-known tool users such as chimpanzees and New Caledonian crows…. “The study shows the creativity and insight that rooks have when they solve problems,” [BBC News], says study coauthor Nathan Emery. Their abilities are all the more remarkable, researchers say, because rooks are not known to use tools in the wild.

In the laboratory tests, researchers devised a series of challenges in which the rooks had to figure out how to release food from glass tubes. The first featured a worm on a platform that would collapse, allowing it to be eaten if a stone were nudged into the tube. All four birds completed the task. They also chose stones of appropriate shape for tubes of differing sizes.The rooks were also quick to realise that long, thin stones would fit in every tube, regardless of its diameter, as long as it went in lengthways [The Times]. But picking up stones was a modest accomplishment compared to what came next.

In a more sophisticated achievement, the birds fashioned a hook out of a straight piece of wire and used it to pull a small bucket up through the glass tube to retrieve the worm inside. “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,” Emery said in a statement [AP].

The study, which will be published in the Proceedings of the National Academy of Sciences, suggests to researchers that the entire crow family may have a deep intelligence that can be turned to tool use if necessary. While New Caledonian crows are known to use tools in the wild, to pull grubs out of holes, researchers note that rooks haven’t faced the same ecological pressures, as they find plenty of carrion and human scraps to keep them well fed. The researchers said that this could mean that an ancient ancestor of the corvids might have evolved the capacity to use tools as well as a complex understanding of the physical properties of materials…. “Because [the rooks] don’t use tools in the wild, the question is why should they have evolved the ability to use tools in the lab and understand the properties of those objects as tools? Is this a form of general intelligence that has been co-opted for tool use?” [BBC News], wonders Emery.

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Image: PNAS

  • p

    I know people who are less creative than birds. Much can be learned from animals.

  • Nick

    I think I know a few of the same people P does.

    More seriously though, birds are descended from dinosaurs, who ruled the roost for millions of years. If they made tools out of wood or stone or fiber, would we recognize them, assuming any made it to the fossilization process? We can barely recognize intelligence in animals we’ve share our entire conscious history with, and have to devise all sorts of tests before we go “yeah, they’re pretty smart.”

    Their genetics have made it through hundreds of millions of years just like ours have. They may have learned a trick or two.

  • Tristan

    Humans generally think of other animals as unthinking automatons, yet we keep finding out more and more that that simply isn’t the case.

  • amphiox

    It would truly be fascinating if we found evidence of dinosaur tool use. But modern birds, particularly the smart ones like the crows, have much larger brains than their dinosaur ancestors. The biggest brained dinos like the troodontids sit within the lower end of modern bird brain power. So it’s likely that much of the mental abilities of modern birds evolved after the split from the dinosaurs, and probably well after the KT extinction.

  • allen

    talking about ‘crows’ brings this memory to light. i was walking across a bridge on a cold and snowy morning hoping for a ride to the nearby ski hill. as i walked i heard a light “thunk” and looked to my right and there on the snow lay a chicken leg bone exactly like the ones i had delivered to many a trash can after devouring the meat held therein.

    “whereupon could this bone have come from?” i asked myself. i looked above and there perched on the street light was a rogue raven looking down on me with that one-eyed look they use as if to say, “dang, i missed.”

    ’nuff said.

  • Grant H

    I’m very impressed.
    Fashioning a hook out of wire requires some understanding about the physical properties of wire. You have to know that a piece of wire is different from say a twig and how.

  • http://TwoSistersArtandSoul Lisette Root

    Perhaps they communicate on a non verbal level? I truly suspect that many many types of creatures do. I think spiders are particularly smart , and birds seem to me to be on another , higher plane of awareness. I know that birds in my life give love to me , and recieve love from me.


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