Do geese, birds and ducks configure (or fly) in a V because they need to conform to a leader?

Question

Do geese, birds and ducks configure (or fly) in a V because they need to conform to a leader?

Answer 1

No its because they draft off of each other.  The leader changes periodically, he falls behind to draft and rest.  Another duck will take his place for a while allowing others to draft off of him.  It actually very efficient that is why they can fly great distances.

Answer 2

I just saw a program that explained this. They fly in a V because it make them aerodynamic. They fly long distances and the V configuration has less air drag. The strongest fly in the first positions, when they get tired they fall to the back and are able to rest.