While known for mimicry, the Blue Jay's most strategic deception is perfectly imitating the scream of a Red-shouldered Hawk. They don't just do this randomly. Observational studies suggest they use the call to clear a feeding area. By letting out a hawk scream near a bird feeder or oak tree, they scatter the smaller birds (chickadees, finches) in a panic, then swoop in to take the food for themselves. It's a calculated, manipulative trick.
Blue Jay art seeds from @BirdsOfBroomfield