Scientists believe the fable of the crow and the pitcher might have been fairly accurate given the new research showing rooks using rocks to raise the level of water where a worm resided… to bring the worm up to their level. ((http://www.telegraph.co.uk/earth/wildlife/5983953/Aesops-fable-is-true-shows-crow-study.html))
They are such incredibly intelligent birds. The other animal who showed fluid mechanics was the orangutan. I will bet corvids are just as smart if not smarter than many of the primates.
You can read more about the studies here.