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Friday, October 5, 2007

Be Aware Crow! Big Brothers Are Watching You

Scientists have launched the avian equivalent of Big Brother in which tiny tail cameras give unparalleled access to the hidden world of the cleverest feathered toolmakers on the planet.
The ingenuity shown by New Caledonian crows in turning sticks, stems and leaves into tools to extract caterpillars and grubs is such that the birds have already been hailed as the Einsteins of the avian world.

Now a new video spying method has allowed Oxford University zoologists to 'hitch a ride' with wild birds on the Pacific island territory where they live to witness undisturbed behaviour, revealing feats that have never been witnessed before.

Observing the crows in the wild is extremely difficult because they are easily disturbed and live in densely forested, mountainous terrain. The secret of the new reality TV footage, published today in the journal Science, rests on miniaturised video cameras with integrated radio-tags - "tailcams" that weigh only 14 grams - that can be stuck on the tail feathers of wild, free-flying birds.

This is the first time that video cameras have been attached to wild crows roaming their natural habitat - most previous work has relied on either studying birds in the lab to show off their intellectual skills, or observing wild birds with binoculars from hides.

'Everyone thought that New Caledonian crows use tools mainly to probe into holes and cracks in rotting wood and tree crowns, but we now discovered that they use tools even on the ground,' said Dr Christian Rutz.

One crow - codename EK1 - was seen probing leaf litter with grass-like stems, which marked a new kind of tool and tool use that decades of conventional observations had missed.

By analysing the footage the team could also work out that the birds averaged eight morsels (such as beetle larvae, small lizards and small fruits) for every hour of ground foraging and hanging on to particularly "good" tools for future use.

'This discovery highlights the power of our new video-tracking technology' said Dr Rutz.

'This is the first time that wild birds have been tracked in this way, and it has already changed our understanding of New Caledonian crow behaviour.'

The tail cams were attached with sticky tape, and were designed so that they did not adversely affect the birds' movements, and could be removed by the crows themselves or would detach after a few weeks during the birds' natural moulting process.

'Observing wild birds this closely in their natural habitat has been one of the final frontiers of ornithological field research,' said Dr Rutz. 'Whilst video footage has been taken before using tame, trained birds, it is only now that we have been able to design cameras that are small and light enough to travel with wild birds and let them behave naturally.

Video tracking should be useful for studying many other bird species that are shy or live in inaccessible habitats. "Potentially, this new video technology could help us to answer some long-standing questions about the ecology and behaviour of many other bird species that are otherwise difficult to study.'

Previous studies on New Caledonian crows by the Oxford group, headed by Prof Alex Kacelnik, have shown that: tool-related behaviour emerges in juvenile crows that had no opportunity to learn from others; crows have a preferred way of holding their tools comparable to the way that humans are either right- or left-handed; adult crows can make or select tools of the appropriate length or diameter for experimental tasks; and one crow, at least, can bend and unbend novel material to match task requirements.

Posted by Ajay :: 5:46 PM :: 0 comments

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