Yet another animal has picked up a tool and put it to use.
Once thought a unique primate trait, toolmaking and tool use have been seen in a variety of animals in recent years. Now add to the list rooks, a bird once featured in European folklore as able to forecast the weather.
Rooks are not known to make or use tools in the wild, but quickly came up with the idea when confronted with problems in laboratory tests, British researchers report in Tuesday's edition of Proceedings of the National Academy of Sciences.
Faced with food that could only be obtained by pushing a small stone off a ledge into a tube, rooks quickly mastered the skill.
And when the stone was placed elsewhere, they didn't take long to decide to pick it up and carry it to the tube, according to researchers Christopher D. Bird of the University of Cambridge and Nathan J. Emery of Queen Mary College, London.
A female bird, Fry, was first to figure out picking up the stone, followed by her mate Cook. A second pair, Connelly and Monroe, also mastered the task.
The birds also succeeded at other tasks involving sticks, wire and even one where they had figure out how to bend a wire into a hook to retrieve an item.
"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.
The wire-bending task repeated the effort of Betty, a New Caledonian crow, who pioneered that skill in a report released in 2002 by the University of Oxford. New Caledonian crows, however, were already known to use tools in the wild.
Many animal species are now known to use tools, ranging from otters and herons to monkeys and chimpanzees. Indeed, Emery and Bird report that as many as 39 species of birds are estimated to use tools in one way of another.
Their research was funded by the Royal Society and University of Cambridge.