Crows have an advanced way of thinking that enables them to develop new behaviours, say New Zealand researchers.
Dr Alex Taylor and colleagues at the University of Auckland report their study of New Caledonian crows today in the Proceedings of the Royal Society B.
"It appears that the crows have some kind of complex cognitive mechanism that allows them to generate innovation," says Taylor.
He says apes, parrots and crows all generate more new behaviours in the wild than other species.
But scientists have long wondered whether this is because they are just faster at learning from their mistakes than other animals, or whether they are specially wired to do so.
Previous research has suggested it is the later, but the subject is a matter of controversy, says Taylor.
In this experiment, Taylor and colleagues tested whether crows were able to combine different bits of previously gained knowledge to solve a new problem.
The crows were presented with a short stick, hanging by a string from a perch near a toolbox containing a long stick, and some food in a hole.
During a previous training period, the crows were given a chance to use a short tool to get food.
They were constantly frustrated because the stick didn't reach the food and eventually ignored the tool altogether, says Taylor.
The crows were also trained to pull up a string that had food on it.
And they were given the opportunity of successfully getting food out of a hole with a long stick - something crows tend to do in the wild as well.
Taylor says the group of crows, which had been trained, were able to use the short stick to get the long stick, and then use the long stick to get the food.
"These crows had never pulled up a tool on a string before and they had never used one tool to get another tool," he says.
Instead, he says, they used their previous experiences of pulling up a string and using a long tool to get food to innovate a new behaviour.
"They showed the ability to use behaviours in a new context," says Taylor.
He says the crows behaviour showed they were thinking about what the short tool would allow them to do.
"They were understanding about how tools can be used in a more abstract sense," says Taylor.