The Formation of Flying Geese is a V-shaped formation of birds, usually geese, flying in unison. This formation is used by many species of birds to reduce air resistance and conserve energy while migrating. The term 'VEE' is used to describe the shape of the formation, which is created by the birds flying in two lines that come together at the front. The leader of the formation changes periodically to ensure that all birds get a chance to rest.