Published online 9 August 2002 | Nature | doi:10.1038/news020805-9


Clever crows know their tools

Birds have rare talent for tool-making.

<mediar rid='m1'/>Crows may be some of the most innovative toolmakers in the animal kingdom, say researchers.

A team at Oxford University, UK, observed Betty, a New Caledonian crow, shaping a hook from a straight piece of wire - and using it to retrieve food1.

The bird had never used wire before, or observed others using wire, and had not been trained. Previously, only humans were thought to make tools out of objects without prior experience. "This is solving a problem which is new in the experience of the animal," says team leader Alex Kacelnik.

Behavioural scientists are finding that some of the cognitive abilities of this family of birds, including crows, jays and magpies, are comparable to those of mammals, says James Ha, who studies primate and crow behaviour at the University of Washington in Seattle. "These guys are right up there with your dog," he says.

In trials, Betty was presented with a straight wire and a bucket of food dropped out of reach down a pipe. Betty would first try to use the wire to lift the bucket; if that didn't work, she quickly fashioned a hook by pulling on the wire with her beak. She successfully gained food in more than half of the trials.

This species of crow, Corvus moneduloides, which is native to the southwest Pacific island of New Caledonia, also makes tools in the wild to retrieve insects from holes in trees or from under leaves on the forest floor2. The birds craft hooked tools out of twigs and shape barbed leaves into tapered implements. The new study explored their tool-making ability in the lab. 

  • References

    1. Weir, A. A. S., Chappell, J. & Kacelnik, A. Shaping of hooks in New Caledonian crows. Science 297, 981, (2002). | Article |
    2. Hunt, G. R.Manufacture and use of hook-tools by New Caledonian crows. Nature 379, 249 - 251 (1996). | Article |