Every now and then you see birds flying in the sky with a V-formation. Ever wondered why they do that? Don’t worry we got an answer for that.
Biologists who have studied bird flight have developed two hypotheses about the possible advantages of these formations. The first hypothesis is that flying in formation provides an energetic advantage. In other words, flying in formation requires less energy than does solo flight. The other hypothesis holds that flying in formation allows each bird to observe the position and flight direction of the other birds in the flock. This visual communication among members of the flock reduces the possibility of collisions and of birds becoming separated from the flock. It also might allow the birds to take advantage of the collective memory of all the members of the flock when they are migrating long distances. The actual formation in which the birds fly could be due to a combination of energetic and visual considerations, or to other factors entirely.
Interestingly, research has shown that the leading bird does not simply block the wind for the following birds. The wings of the bird create wing-tip vortices, which are regions where the air behind the bird’s wing moves in a twisting motion. Figure 1, below, shows the vortex created by the wing of an airplane. Note that there is a region where the wind in the vortex is moving upward. This upward-moving wind can create a wind upwash, which provides a lift to the following bird. The paper by Cutts and Speakman in the Bibliography provides more details of this phenomenon.