Flying in Vee Formation We commonly see ducks and geese flying in a regular V-shaped formation, but why they do so remains something of a mystery. One theory has been that all but the lead bird are able to gain lift from the wing-tip vortices produced by the bird in front of them. Those vortices are formed by air rushing up over the tip from the high-pressure area under the wing into the low-pressure area above the wing. The following bird, if it is in just the right position, will remain within the upward flow of the vortices. Calculations indicate that such an advantage could greatly boost the range of a flock of birds over that of a bird flying alone. Theoretically, to be most efficient, the wing-tip of a following bird should remain within about one-fourth of a wingspan from that of a bird in front of it. Motion pictures of flying flocks reveal, however, that in practice Canada Geese do not travel in formations that allow flight efficiency to be much increased by this mechanism. Instead, scientists have suggested that flying in vee formation is a way of maintaining visual contact and avoiding collisions. Further study is clearly required before the reason for flying in vees becomes clear. SEE: Skimming: Why Birds Fly Low Over Water. Copyright ® 1988 by Paul R. Ehrlich, David S. Dobkin, and Darryl Wheye.