When a bird flaps its wings it redistributes the air around it, leaving whirling eddies behind. Some gregarious species, such as the Canada goose, have learned to take full advantage of this upwardly spinning air by flying in wedge or V-shaped formations. This "drafting" allows the geese to travel at an easier pace throughout their flights. Researchers have found that geese flying in Vs can travel as much as 70 percent farther than they could otherwise.

When traveling long distances, tundra swans fly in the same V-shaped formations as geese, and for the same reason. The resistance of the air is less as each bird flies in the widening wake of its predecessor. The leader has the hardest work to do as he or she "breaks the trail." Luckily, the lead bird is relieved in frequent intervals. The flocks are constantly fracturing and reassembling their formations, with a different individual at the head each time.

Besides the many flocks of Canada geese and tundra swans, the other species who travel in V-shaped flocks include ducks, cormorants, shorebirds and gulls, plus other species of geese and swans. Throughout most of November, I'm filled with awe each evening at sunset, as one V-formation after another of Franklin's gulls makes its way to Lake Waconia, where these social birds will spend the night as a huge surface water flock.

Jim Gilbert's Nature Notes are heard on WCCO Radio at 7:15 a.m. Sundays. His observations have been part of the Minnesota Weatherguide Environment Calendars since 1977, and he is the author of five books on nature in Minnesota. He taught and worked as a naturalist for 50 years.