Flocks of birds like geese, pelicans fly in V formations to make flight easier.
In V formations, when a bird flaps its wings, the air behind the bird gets pushed downward creating a downwash, while the air towards its sides gets pushed upward, creating an upwash. This produces rotating vortices.
If another bird flies in these upwash zones, it gets a free lift and glides due to reduced air resistance. Thus, birds are able to fly long distances without putting much effort and maintaining a
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