AUGUST 10, 2016
by John Hopton
Understanding of crows' crafting and use of tools has been slow to progress, but just took a major step forward through observing wild New Caledonian crows.
It was back in 2002 that a captive crow, Betty, blew scientists' minds as they watched the bird bend twigs into hooks in order to extract buried food.
The University of Oxford, UK, researchers wondered if the trait may have emerged in captivity, but a new study of the wild crows from New Caledonia in the South Pacific suggests the trait may in fact be part of the birds' natural behavior.
Along with crows, captive rooks have previously been seen to fashion tools in such a way. Wild crows have also long been known to use twigs to get at food. But seeing wild birds fashion tools represents a new development.
Dr. Christian Rutz, from the University of St Andrews in Scotland, who is lead author of the new study published in the journal Open Science, explained how short-term capture of crows from the tropical forests of New Caledonia helped to aid understanding.
Rutz said: "This means we can test them under highly controlled experimental conditions - but the kind of experiments we do there, they don't look at how smart these animals are, they ask what sort of tool behaviour they express naturally."
How did they test for this ability?
The team used wooden logs with appealing food buried inside them, which were presented to the crows.
"The only other thing we provided in the aviary was the plant material, which we knew they naturally used for tool-making in the wild," explained Rutz.
"So the task was very simple, we asked our subjects to make tools, then use these tools to extract the hidden food."
An impressive 10 of the 18 wild-caught birds made tools from the twigs.
It wasn't entirely necessary for the birds to make tools in order to reach the food, but many of them did so anyway.
We think the bending helps with the tool ergonomics," said Rutz.