Researchers have been experimenting with six African grey parrots at a rescue centre in Vienna, Austria, and discovered that the birds are smarter than the average 2-year-old.
The study also found that parrots are the only animals able to understand noise-related causal connections, apart from great apes.
The experiment consisted of the birds choosing between two closed boxes, one of which had a piece of walnut in it and rattled when shaken. The other container was empty and could be shaken without making a noise.
The parrots showed that they knew how to detect hidden food by hearing the rattling in the box.
The research group was led by Dr Christian Schloegl, from the University of Vienna. He recorded the findings in the Proceedings of the Royal Society B: Biological Sciences journal.
His notes read: "Human children solve this task from an age of 3 to 4 years, and the birds' success rate was comparable to those of the 3-year-olds."
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