Parrots are known to be highly intelligent birds but until now it had not been proved that they can reason.
We know that humans and other great apes do it. Now a parrot has shown it can use logical reasoning to work out where food is hidden.
Sandra Mikolasch of the University of Vienna's Konrad Lorenz Research Station in Austria and her colleagues first checked that seven African grey parrots (Psittacus erithacus) had no preference for two types of food, seeds or walnuts.
Each parrot watched a researcher hide a walnut under one opaque cup and a seed under another. Then the researcher hid the cups behind a screen, removed one of the treats and showed the bird which one had been taken. Finally, the screen was removed to see if the parrot could work out which treat must remain, and under which cup it must be.
Only one of the parrots, a female called Awisa, was able to do this. She chose correctly in three-quarters of the tests – 23 out of 30.
As with similar studies using apes, not all parrots could solve the problem. The other parrots chose more randomly, suggesting they hadn't worked out what was going on. It seems that parrots, like apes show individual differences in their abilities to reason.
"So far, only great apes have been shown to master this task," says Mikolasch. "So we now know that a grey parrot is able to logically exclude one possibility in favour of another to get a reward, known as 'inference by exclusion'."
The confirmation that parrots can reason adds to our already considerable knowledge about their complex mental abilities. The term ‘bird brains’ couldn’t be further from the truth. The more we learn about these fascinating birds the more one must surely question how long it will be generally viewed as acceptable to keep them as pets, imprisoned in cages for our own reasons.
Thanks to Nick Craig (twitter @nickcraig) for the use of the photograph.