Betty bent a straight piece of garden wire into a neat hook to lift a food-baited bucket from a vertical tube in a laboratory at the University of Oxford in 2002.
At the time, it was known that New Caledonian crows manufacture dtools from twigs in the wild, but it was thought highly unlikely that this involved bending. The resulting paper from the experiment suggested that Betty had spontaneously come up with a clever solution after understanding the experimental task.
This shook the field of comparative cognition and was regarded as one of the most compelling demonstrations of intelligence in a non-human animal.
But recent field experiments by biologists at the University of St Andrews have found that tool bending is part of New Caledonian crows’ natural behaviour.
Dr Christian Rutz was leader of the project, the findings of which are published in Royal Society Open Science.
Dr Rutz said: “Most birds trapped sticks underfoot before bending the tool shaft by bill, but one also pushed tools against the logs to flex them, and another wedged them upright into holes before pulling the shaft sideways, just as Betty had done.
“It turns out, the twigs that wild crows select for making their tools are pliable.
“Our study is a powerful reminder of the importance of basic natural history research.
“When my Oxford colleagues studied Betty’s cognitive abilities almost 15 years ago, very little was known about how these birds make and use tools in their natural tropical habitat.
“Our discovery of tool bending in wild New Caledonian crows has come as a complete surprise, and was the result of patient field research.”
The researchers provided the wild-caught crows with juicy treats hidden in wooden logs, as well as their preferred plant material to manufacture tools.
New Caledonian crows live in the remove tropical archipelago of New Caledonia, South Pacific, where the research for the study took place.
Dr Rutz said the researchers were “absolutely over the moon” when the birds began making and using tools in their field aviaries.
Some of the crows vigorously bent their twig tools during processing in the same manner as Betty had bent wire in the Oxford experiment.
This time, however, bent tools were not required to solve the task.