May 26, 2009

Study Reveals Rooks Have Discerning Taste In Tools

Researchers have learned that rooks have the ability to make and use tools in order to complete certain tasks.

Researchers from the University of Cambridge and Queen Mary, University of London, noted that although rooks, which are related to New Caledonian crows, are not known to use tools in the wild, they quickly learned to do so in laboratory tests.

"This finding is remarkable because rooks do not appear to use tools in the wild, yet they rival habitual tools users such as chimpanzees and New Caledonian crows when tested in captivity," said lead author Chris Bird of the University of Cambridge.

Researchers studied four birds in captivity: Fry, her mate Cook, as well as Connelly and Monroe.

Each of the birds successfully mastered the task of choosing the proper stone to be dropped into a tube that would release food from a transparent box.

"We have found that they can select the appropriate tools out of a choice of tools and they show flexibility in the types of tools they use," said Bird.

Researchers also sought to determine whether the rooks had the ability to bend wire to make a hook to retrieve items.

"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," said Nathan Emery of Queen Mary, University of London.

A previous study in 2002 showed that Betty, a New Caledonian crow, was able to bend wire to make hooks.

"The study shows the creativity and insight that rooks have when they solve problems," said Emery.

Researchers also noted that rooks could use two tools in succession, also known as metatool use. The ability has only been previously shown in primates and New Caledonian crows.

"Tool use is probably very important for these crows because of their ecology - they may get a large proportion of the protein they need from these grubs."

"And it has been suggested that tool-use is a trait unique to that species that might have evolved because of ecological pressures," he added.

The new study was supported by the Royal Society and University of Cambridge. It has been published in the journal Proceedings of the National Academy of Sciences.


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