The crow’s name was Betty. And she was on her way to stardom. A gaggle of Oxford University scientists watched in wonder as she casually picked up a piece of wire in her cage and then used a nearby object to bend it at one end, transforming the wire into a hooked tool. That tool allowed Betty to hoist up a small container of meat – delicious pig’s heart – from inside a plastic tube. Lunch was served.

Back then, in 2002, Betty’s feat was a source of amazement. How did this crow solve such a complex problem so spontaneously? It suggested mental acrobatics akin to our own. This, the headlines read, was one stunningly clever crow.

Except that Betty was not quite as special as some first thought. Many years later, research showed that New Caledonian crows are habitual tool-benders. In the wild, they do it all the time. Observers had initially been startled by Betty’s behaviour because it looked as though she had come up with the design for her hooked tool on the fly. Like an engineer inventing a new machine. In reality, New Caledonians have evolved to make hooked tools from soft twigs as part of their usual foraging activity.

It was less a moment of genius – and more an expression of her nature.

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“I don’t want to downplay her cognitive abilities,” says Christian Rutz at the University of St Andrews. “At the very least, it forces us to reassess how insightful Betty’s behaviour was.”

New Caledonian crows belong to the corvid family of birds – as do jackdaws, rooks, jays, magpies and ravens. In recent years, the brains of these birds have been studied ever more closely. There is no doubt that some of them display impressive cognitive abilities. But intelligence is a murky subject. What exactly is it, in the first place? And why has it evolved?

Corvids are helping us to answer these questions.