Clever New Caledonian crows can use three toolsBy Rebecca Morelle
Science reporter, BBC News
New Caledonian crows have given scientists yet another display of their tool-using prowess.
Scientists from New Zealand's University of Auckland have found that the birds are able to use three tools in succession to reach some food.
The crows, which use tools in the wild, have also shown other problem-solving behaviour, but this find suggests they are more innovative than was thought.
The research is published in the Proceedings of the Royal Society B.
The team headed to the South Pacific island of New Caledonia, the home of Corvus moneduloides.
Finding that the crows could solve the problem... was incredibly surprisingAlex Taylor
They are the only birds known to craft and use tools in the wild.
The discovery that they whittle branches into hooks and tear leaves into barbed probes to extract food from hard-to-reach nooks astounded scientists, who had previously thought that ability to fashion tools was unique to primates.
And further research in the laboratory and the field has revealed that New Caledonian crows are also innovative problem solvers, often rivalling primates. Experiments have shown that the birds can craft new tools out of unfamiliar materials, as well as use a number of tools in succession.1. String is attached to perch2. Short stick attached to string3. Long stick out-of-reach behind bars - can be reached with short stick4. Out-of-reach scrap of meat - can be reached by long stick