Birds are “like chorus girls”—and not just because of the feathers. When the leader makes a move, the rest react almost instantaneously, says the National Audubon Society’s Frank Gill. This visually triggered wave of reaction is so quick, it’s not even noticeable to binoculars-using bird watchers. Also, to save energy, birds ride the air coming off the wings of the fowl in front, keeping them in flawless formation. And some birds, like geese, honk to signal their position to the flock. And you thought they were just in a hurry. —Sally Atkinson
