A New Caledonian crow seeks to prise out its dinner with a twig. British researchers have uncovered the secret behind the corvid's impressive use of rudimentary tools, binocular vision and a long, straight bill.
TV AND WEB RESTRICTIONS**PART MUST COURTESY 'JOLYON TROSCIANKO'**~ INTRO: New Caledonian crows are well-known for their ability to use tools but new research, recorded on video, reveals the impressive binocular overlap of the celebrated bird's vision which helps it seek out food. Researchers from the British universities of Oxford, Birmingham, and St Andrews got a bird's eye view of the crow at work by placing an ophthalmoscope video camera inside a baited tube and studying how the corvid uses its overlapping vision and straight bill to help it access larvae. Jim Drury has more. STORY: A New Caledonian crow seeks to prise out its dinner with a twig. British researchers have uncovered the secret behind the corvid's impressive use of rudimentary tools.....binocular vision and a long, straight bill. They used an ophthalmoscope video camera to record the field of view and eye movement of three captive birds as they levered larva from a tube. University of Birmingham researcher Jackie Chappell says the corvid used both eyes to help it judge the distance to its hard-to-access prey. SOUNDBITE (English) DR JACKIE CHAPPELL, LECTURER IN ANIMAL BEHAVIOUR AT UNIVERSITY OF BIRMINGHAM, SAYING: "The bird definitely has there both eyes looking down the tube, so it's converging its eyes, so it can use both to look down the tube and see what the tip of the tool is actually doing and you can see it's got the food nearer to the entrance of the tube and in a moment will actually be able to get the larvae out. There it is. It gets it reward." The study suggested the New Caledonian crow's forward facing eyes provide almost 50 percent more binocular overlap than non-tool-using corvids. Its straight bill also helps. SOUNDBITE (English) DR JACKIE CHAPPELL, LECTURER IN ANIMAL BEHAVIOUR AT UNIVERSITY OF BIRMINGHAM, SAYING: "This is holding the tool across their bill, in their bill, but pressing one side of it against their cheek which helps to stabilise it and gives them a better grip on it, whereas when the aperture was narrower then they tended to just be able to use one eye because it was a much smaller hole and they tended to favour a straighter grip." The team say the New Caledonian crow demonstrated the greatest binocular overlap ever measured in a bird species. University of Oxford lecturer Auguste Von Bayern says corvids, including this rook, are highly cogniscent. SOUNDBITE (English) AUGUSTE BAYERN, MEMBER OF BEHAVIOURAL ECOLOGY RESEARCH GROUP AT UNIVERSITY OF OXFORD, SAYING: "Corvids count among the most intelligent birds, in terms of their brain cells relative to their body size, they have huge brains, together with parrots probably the largest brains in birds and in the last ten years research has shown that they are at comparable level to apes, our closest relatives, and sometimes even outperform them in tests, so they're terribly clever." Dolphins, elephants and cockatoos are among non-primates found to use tools. But the researchers believe this study demonstrates the first evidence of body features tailored for tool use in non-primates. Among the brightest species in the avian kingdom, the bird really does have plenty to crow about. UPSOT: CROWING OF A NEW CALEDONIAN CROW