My favourite bit about the intelligence of rooks : if I go outside to throw out large bits of bread etc., there is immediately a loud 'rook' conversation going on in the spinney, basically saying "Hey guys, she's feeding us again" and within seconds, not minutes - there they are, en masse, and all the bread has gone. But they ignore the small seeds I throw down for the other small birds, TOO difficult to get a good mouthful and take flight!