The chief advantage of ‘V’ formation is that the birds following the leader in two arms of the ‘V’ formation do not have to exert very hard to remain afloat. As the leading bird beats its wings, the air is displaced upward. The upward draught of air assists the immediately following birds in remaining airborne with considerably less effort. These birds, in their turn, make flying easier for those that follow by creating another upward draught of air and so on.
Of course, the leading bird does not receive such assistance. This means that it would get tired sooner than the others. The birds solve this problem by taking turns to lead the flock.
When you see a ‘V’ formation of the birds overhead, make sure to observe the switch over of the leading position. There are many more interesting habits and patterns that we can observe in the avian world.