Why do geese fly in a 'V'?

In Berlin and the neighboring state of Brandenburg, this is a common scene in autumn: first you hear them, then you see them. We're speaking of flocks of honking geese flying in a "V" formation across the sky. But why do the birds choose to fly in this certain formation as they head to southern destinations?

According to the "Everyday Mysteries" feature by the Library of Congress website, the birds make use of this formation to save energy and to be able to communicate well. "Each bird flies slightly above the bird in front," the website writes. That causes a reduction of the wind resistance. The birds alternate who's leading, they begin in front and fall back when tired. "In this way, the geese can fly for a long time before they must rest." The second reason is communication. It's just easier to keep track of every bird in the group, when flying in a "V" formation.