Inferational

Grey parrots are pretty clever, as this report of a recent experiment shows:

... the team showed the birds two opaque boxes, one of which contained food. The researchers then shook the boxes allowing the birds to hear that something was inside just one of them. The birds then guessed correctly which box had the food in it, walked over and tipped it over and ate their treat. Next, however, the researchers tried shaking just the empty box, producing no sound. This time, the birds were able to infer that the food must be in the other box and ran to it when given the chance, accomplishing a feat the team says, humans can’t handle until the age of three. They also say that dogs and monkeys failed when given the same test and that it seems that other than the birds, only great apes and human are known to be capable of such inferential thinking.