Who's a brainy boy then? African grey parrots have outperformed human 2-year-olds in a test of reasoning.
Researchers tested six African greys at a parrot rescue centre in Austria.
During a series of experiments, the birds were given the choice between two closed boxes, one of which held a piece of walnut and rattled when shaken. The other was empty so could be shaken without making a noise.
The parrots knew how to detect hidden food rattling in a shaken box.
But they also worked out, almost instantly, that if a box was shaken and made no noise, the food was in the other container. Choices were made by a parrot walking to a box and turning it over with its beak.
In similar tests, most animals - and even small children - get confused about the way shaking and noise relate to the presence or absence of a hidden reward.
The scientists, led by Dr Christian Schloegl, from the University of Vienna, wrote in the journal Proceedings of the Royal Society B: Biological Sciences: "We found compelling evidence for the ability of African grey parrots to use noise created during the shaking of containers to detect hidden food."