Researchers studying Caledonian crows, known for holding twigs in their beaks to dig out insects, have now determined that they value certain tools over others and will actually try to protect them.

The Daily Mail reports that biologists from the University of St Andrews found that the hooked tools, which are up to ten times more effective than straight tools, are valued by the crows.

And because of this and the difficulty in finding or creating such tools, crows will go to great lengths to protect them.

Once the crow has used the hooked tool to dig out an insect, as an example, it must drop the tool to eat.

Researchers noted that the crows were more likely to stand on the hooked tool while eating, in order to prevent other crows from stealing it, than a straight tool.

And once they were finished eating, the crows were more likely to hide these favourite tools in such things as tree holes, and retrieve them later when they are ready to look for food.

Speaking on behalf of the research team, Biology professor, James St Clair said:

‘It was exciting to see that crows are just that bit more careful with tools that are more efficient and more costly to replace.

“This suggests that they have some conception of the relative ‘value’ of different tool types.”

READ: Not so bird-brained after all! Crows keep their most special tools extra safe — suggesting they have some concept of the relative ‘value’ of items

Crows also manufacture tools

Researchers from Oxford University, who were also studying Caledonian Crows, noted that one, named Betty, was adept at making hooked tools from a piece of wire.

The National Geographic explained how this accidentally came to light:

Betty’s toolmaking abilities came to light by accident during an experiment in which she and Abel had to choose between a hooked and a straight wire for retrieving small pieces of pigheart, their favorite food. When Abel made off with the hooked wire, Betty bent the straight wire into a hook and used the tool to lift a small bucket of food from a vertical pipe. This experiment was the first time the crows had been presented with wire.

READ:  “Crow makes wire hook to get food”. National Geographic News AND Crow that bent wire to retrieve food was acting naturally, scientists discover