Birds fly in a V formation primarily to save energy during long flights, especially migration. Each bird flies slightly above and behind the one in front, to catch the uplifting air (upwash) created by the wingtip vortices of the leading bird. This reduces wind resistance and allows birds to glide more efficiently, conserving energy. Birds also take turns being the leader since the frontal position is the most energetically demanding. Additionally, flying in a V formation helps them keep visual contact and coordinate their movements more easily within the flock.

Aerodynamics and Energy Efficiency

• The wingtip vortices of a bird create an updraft that assists the following bird in supporting its weight.
• Studies show birds flying in a V formation have lower heart rates and flap their wings less frequently compared to flying alone.
• A formation of 25 birds can increase their flying range by 71% and reduce flying speed by 24%, greatly improving energy savings.

Coordination and Communication

• The V shape makes it easier for birds to visually track each other and maintain formation.
• Birds coordinate wingbeats to maximize the benefit from the uplift created by the bird ahead.
• The leadership rotates among individuals to spread the fatigue of leading.

This V formation strategy is also adopted by some aircraft to conserve fuel, showing its efficiency in both biological and human-engineered flight.