Tuesday, 20 September 2011

Crows Use Mirrors To Find Food

BBC Nature (Sept. 20, 2011) Clever New Caledonian crows can use mirrors to find food, according to scientists.

Researchers from the University of Auckland, New Zealand, tested wild-caught crows' reactions to mirrors.

The crows did not recognise themselves but found cached food items by studying their reflections.  The results put the birds in an elite group of species - which includes primates and elephants - known to be able to process mirror information.

New Caledonian crows (Corvus moneduloides) are known for their intelligent and innovative use of tools, such as twigs, which they use to fish nutritious insects out of holes and crevices.

Mirror experiments with other members of the same family of birds, the corvids, have found that magpies recognise their reflections but jungle crows do not.

In this study, published in the journal Animal Behaviour, psychologists examined the recognition skills of the notoriously clever New Caledonian crows.

Scientists captured 10 wild birds and placed them in large cages in order to record their behaviour in response to mirrors.

All the crows reacted to seeing their reflections as if they were encountering another crow; the birds made rapid head movements, raised their tails and even attacked the reflection.

Lead researcher Felipe S Medina Rodriguez said the crows' antagonistic reaction to their mirror image "was not surprising". He explained that an animal usually had extensive exposure to mirrors before it began to display an understanding that the image it was seeing was itself.

When the crows moved away from the mirror and lost sight of their reflection, they frequently searched behind the mirror to locate the "other" bird.

The researchers think that the behaviour was probably caused by the birds' lack of experience of mirrors; similar reactions have been recorded in primate infants and two-year-old children.

The second part of the experiment, though, revealed some surprising findings.

The scientists devised a task to test whether the crows could use mirrors to locate cubes of meat that were hidden from direct view.

All of the crows tested appeared to understand how the meat's reflection correlated to its location.

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