I've mentioned Alex the genius parrot, but here's a different kind of bird. Snowball, a sulphur-crested cockatoo, dances. His YouTube performance to "Everybody" by the Backstreet Boys (well, no one said he had taste) is a global sensation, and researchers who tested him by varying the music report the parrot is, indeed, following the beat. Why is not clear, but it seems to have something to do with the ability and inclination to mimic voices: an African gray parrot (like Alex) and a few other animals have done it, but monkeys and other creatures who are not natural mimics can't be coaxed to dance. It's another reminder of how puzzling the mental world of animals remains despite all the research.
THANKS to Kris Winkler for alerting me to Mr. Snowball's abilities.