National Geographic : 1975 Jul
of 300,000 Adelie penguins in Antarctica, to round up thousands of pink-footed geese in Iceland, to sit among harems of fur seals on the Pribilof Islands in the Bering Sea, or to take inspiration from the wandering alba tross as it soars majestically above the south ern oceans? All these experiences have been mine, and they are unforgettable, yet for me the lift-off of whistling swans from Chesapeake Bay on spring migration equals or even surpasses, in emotional and scientific impact, those other more exotic adventures. I remember the great spring assemblies of the 1960's at Eastern Neck National Wild life Refuge on Maryland's Eastern Shore. Rarely were there fewer than 3,500 swans gathered on the shoals-those that had win tered there, and others on stopover from southern Virginia and the Carolinas. The air was filled with their mellow baying-"Wow HOW-oo, wow-HOW-oo!" Just before sunset small groups of swans began swimming slowly, sleek and straight necked, toward the sandbar and the open bay. The first flock prepared for flight, swimming faster, baying louder. Then a new sound-the patter of black-webbed feet and wing tips slapping the water as the powerful birds, each weighing as much as twenty pounds, gained speed to lift themselves into the air. Flying low, they climbed on the back of the With a confident stride, the author, an ex-cross-country champion, over takes a cygnet (right) that he later bands and weighs (left) on Alaska's tundra. A floatplane doubles as a swanherd, taxiing gently to point swimming birds to shore, where, in August, flightless molting adults and their cygnets offer a challenge to the fleet of foot. A professor at Johns Hopkins Uni versity, Dr. Sladen heads a research program funded in part by the Na tional Geographic Society, to probe the habits and migrations of swans. Over the past five years some 2,500 whistlers have been fitted with color coded neckbands that allow long-term observation of individual birds. Oth ers have been fitted with lightweight radio transmitters as well, and tracked along their flyways from Chesapeake Bay to the Canadian prairies. southeasterly breeze, rhythmically winging toward the reddening horizon. They were on their way, at the start of an incredible journey that would end on the ice chilled North Slope of Alaska, or in the river deltas of Canada's Northwest Territories. Under the midnight sun the birds would nest and rear their young. Flocks of Migrants Span the Sky In the eastern spring migration they fly en masse, not in a dense cloud of thousands like some ducks, but as an almost continuous sky parade of small flocks, ten to a hundred or more birds in each. The sky is mottled with far-reaching phalanxes that may stretch from the marshes of the East Coast to the Appalachian Mountains. During fall migration, from late September until November, North America's estimated 100,000 whistling swans come back across the continent, the western Alaska population reaching wintering grounds as far south as California, and the eastern birds dispersing along the mid-Atlantic region from Delaware to North Carolina. We know less about these fall migrations, but it appears that this air borne cavalcade flies at a higher altitude, and that the birds may travel nonstop for 1,350 miles from the plains to the coast. But bad weather can cause them to swing low, some times with surprising results.