Nature Notes: Why birds fly in a V-shaped wedge
Besides the many flocks of Canada geese and tundra swans we observe traveling in V or wedge-shaped formations, other species of swans, geese, ducks, cormorants, shorebirds, and gulls also regularly arrange themselves in that pattern. Well into 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 large surface water flock.
When a bird flaps its wings it disturbs the air and leaves whirling eddies behind. Some gregarious species such as Canada geese have learned to take advantage of the upward disturbed air created off the wings of others in the flock by flying in a V-formation. Each bird thus adds the lift lost by the bird ahead to its own. This “drifting” allows the geese to travel at an easier pace through their long flights. Researchers have found that geese flying in Vs can fly as much as 70 percent further than they would otherwise have been able to.
When traveling long distances, tundra swans fly in the same 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” but is relieved at intervals and drops back into the flock to rest.
What’s happening outdoors now?
Tundra swans are seen overhead and we hear their muffled musical whistles — a wonderful sign of fall. They are coming from their summer range, which is mainly north of the Arctic Circle and heading for their wintering range along the Atlantic coast. A good area to see hundreds, sometimes thousands, of tundra swans is the Mississippi River and its backwaters between Minneiska and the Brownsville area. The last flocks of migrating red-winged blackbirds, common grackles and American robins move through. Both white-throated sparrows and dark-eyed juncos forage beneath backyard feeders. Heated birdbaths and crabapple fruit invite flocks of cedar waxwings.
Truckloads of newly cut Christmas trees — firs, pines and spruces — are seen on highways heading for retail sales lots. It’s time to wrap young tree trunks, especially those of fruit trees and maples, for winter protection from both sunlight and rodent damage. Rutabagas and parsnips sweetened by the frosts can be dug for delicious eating or stored for winter use.
On Nov. 8 a year ago
We had a partly sunny day with a low temperature of 34 degrees and a high of 47 degrees F. There were still beautiful lingering fall leaf colors, including reds on winged euonymus shrubs and Boston ivy; and golden-yellows on aspens, eastern cottonwoods, Norway maples, weeping willows, and Lombardy poplars. Geraniums, alyssum and petunias continued blooming. Big rafts of American coots lingered on Lake Waconia. American robins fed on crabapple fruit.
Jim Gilbert’s Nature Notes is a regular feature of The Norwood Young America Times.