The construction of the wedge is of practical importance: it facilitates flight to all members of the pack!
Typically, ahead of the casing flies the most powerful bird - leader. The air flows around her body with the least resistance. In a similar shape of the entire flock. Birds instinctively adhere to an acute angle and is easy to move forward, guessing a minimum of resistance and sensing whether each of them is in the correct position relative to the leader.
In addition, this arrangement birds explains another important reason. Flaps are the first birds to create an air - wave upward flow of air. It facilitates the movement of the wings of the birds flying behind them. It is, as a rule, the weaker birds. The whole flock is connected between an air wave, and the flap is in resonance with it. The figure of this wave can be obtained by an imaginary line connecting the ends of the wings at a certain point in time.
Correct wedge bird flock flying, if there is no wind. If there is a strong side wind, the birds are attached to the leader with the side where the ascending air flow from Mach his wings maximum. In this case, the shape of the pack is a jamb.
So birds use the laws of physics to make a trip, saving their strength, and to help the weaker ones.