Specivity
Sometimes, I wish I could identify bird specie by the songs they sing. That way, when there's a robin, or a sparrow, warbling outside my window at five a.m., I can yell: "I'M GOING TO KILL YOU, SPARROW!", instead of just "YOU'RE DEAD, BIRD!!!"
That way, the sparrows will always know I'm talking to them, and not some other bird.