Ravens are apparently the most intelligent of the corvids, that most intelligent bird family. In a well-known experiment, when meat was dangled by a string from a perch, crows eventually gave up trying to grab it by flying at it. A watching raven then flew on to the perch, and on its first try successfully pulled the string up with its beak, stood on that part of the string and then pulled up the rest of the string bit by bit until it could reach the meat.