But have they ever tested the aero dynmaic properties of the L and Q formations? Those birdbrains could be missing out.

Most of us have probably seen large groups of migrating birds like geese or ducks flying in formation. These large groups of birds are particularly common in late autumn and early winter when birds migrate from their summer habitat in Canada to the warmer climate of the southern United States. Such groups of birds will typically fly in a large "V" shape with one bird in the lead and others trailing behind in two lines.

Scientists who have studied formation flight believe that birds fly in this way for two reasons. The first reason is that the shape of the formation reduces the drag force that each bird experiences compared to if it were flying alone. This decrease in drag occurs thanks to the formation of wingtip vortices described in previous articles.

The majority of the benefit goes to the birds further aft, but the front bird does still gain some reduction in drag. The presence of the two birds flanking the leader helps to dissipate the downwash off the lead bird's wingtips and reduces the induced drag this bird experiences. These two flanking birds also benefit from a similar reduction in drag if outboard birds flank them as well. In other words, the birds in the middle of each of the lines forming the V are in the best position. These birds benefit from the upwash off the lead birds as well as off the trailing birds. This additional bonus means that birds in the middle experience less drag than either the lead bird or the bird at the end of each line.

Even though the V formation benefits all of the birds, the bird in the lead position has to work the hardest. When this bird tires, it will drop out of the lead position and fall further back into one of the lines of the V. Another bird from further back will rapidly move forward to take the leading position and maintain the formation. The two birds in the furthest trailing positions also tire more rapidly than those in the middle, so these positions are also rotated frequently to spread the most fatiguing locations throughout the flock. This cyclical rearrangement gives all birds the responsibility of being the leader as well as a chance to enjoy the maximum benefits of being in the middle of the formation. This sense of teamwork comes naturally since even the youngest members of the flock rapidly realize that it takes less work to fly in a V formation than it does to fly alone.

Why do birds fly in a v-formation? [Aerospaceweb.org]