“V’s” of migrating Canada Geese are a common sight and sound in the Northeast during October. The inevitable question arises: why fly in a V formation? In part, because it conserves energy. But exactly how does it do this?
As the lead goose flaps, it creates tiny vortexes (circular patterns of rotating air) swirling off its wings as well as into the space behind it. The vortex behind a goose goes downward, while the vortexes on either side of its wings go up. If a goose flies directly behind the goose in front of it, air will be pushing it down. If it flies off to the outer side of the goose in front of it, air is pushing upward and the goose will get a slight lift, making flying easier.
Picture two geese flying behind and to the outer sides of the lead goose. Additional geese, in order to avoid the vortex behind the lead goose as well as the vortexes directly behind the next two geese, will fly behind and to the outside of the wings of the two birds in front of them, getting a lift and forming a “V.”
Because the lead goose has no vortex to get a lift from, it tires more easily than the other geese. It periodically falls back and is replaced by another goose in the formation. This cooperative process of taking turns leading the flock minimizes the need for the birds to stop and rest.
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