Queen of the corvids: the scientist fighting to save the world's brainiest birds

A pioneering research laboratory in Cambridge proves that corvids are delightfully clever. Here, its founder reveals what the crow family has taught her - and her heartbreak at the centre's closure Leo, an 18-year-old rook, is playing mind games. It's a street-corner classic - cups and balls. Only this time the venue is the Comparative Cognition Laboratory in Madingley, Cambridge, and the ball is a waxworm. Leo - poised, pointy, determined - is perched on a wooden platform eager to place his bet...