Crows' feats of intelligence have animal experts ravin'

Species off coast of Australia amazes researchers by using series of tools to get hard-to-reach treats

Aug 05, 2009 04:30 AM

Sheryl Ubelacker
The Canadian Press

It's long been considered an insult to call someone a "birdbrain." But experiments with one species of crow suggest that referring to someone this way might actually be a compliment.

Experiments by researchers at Oxford University show that New Caledonian crows in captivity spontaneously used up to three tools in the correct sequence to achieve a goal – a feat never before seen in non-human animals without explicit training.

Five out of seven birds tested figured out how to extract different lengths of sticks from tubes so they could ultimately get one long enough to fish out a morsel of food at the bottom of the deepest tube.

In all, the crows needed three sticks of different lengths to achieve their objective of reaching the food – and four of the five successful birds came up with the sequence needed on the first try.

"It is amazing to see. It was wonderful to watch," said zoologist Jo Wimpenny, lead researcher of a paper published in this week's issue of the journal PLoS One.

"They use tools naturally in the wild," she said of the crows, which populate the New Caledonia and Loyalty islands off the east coast of Australia.

Wimpenny said the Behavioural Ecology Research Group at Oxford decided to set up an experiment after observing one of the birds fashion a tool to get at some food.

In the experiment, food was placed at a tube depth that made it reachable with only one length of stick.

But getting that stick required employing two others in sequence. The crows had to use a short available tool to drag in a longer out-of-reach tool, then use that lengthier tool to retrieve the correct longest one.

They could then use the longest stick to reach for the food way down in a tube.

Using tools to make or retrieve other tools has long been considered a hallmark of human intelligence, and has often been interpreted as evidence of advanced cognitive abilities, such as planning and analogical reasoning.

See video at: http://www.thestar.com/sciencetech/article/676302