Blue Jays are also a very smart bird (same general family as crows)...They are easy to teach to catch peanuts in mid air etc...they often become tame enough to take peanuts out of an open hand...
They learn to use tactics like imitating the sounds of hawks to scare other birds away from feeders...they also learn to use the sun to cast their own shadows over other feeding birds for the same purpose...
I sic my feral cats on them. Aren't the Blue Jays favored to win the World Series this year?