My wife's African Grey whistles the theme fro "Bridge on the River Kwai"(Col. Bogey March). Fun to watch her hop to attention whenever it is on TV. also sings "Jingle Bells" in season. Especially likes a Harvey Reed piece which I don't know the name of. Dances to it. I know the album title so I guess I'd better get it.
My White Fronted Amazon is a critic. Tried to take a chunk out of me once when I sang to him. He's probably right. I've been sneaking a little more to him gradually.