Nov/Dec 2012For Wildlife Watchers: Tundra Swanby Rob Simbeck, photograph by Stewart Grinton
A few hundred tundra swans visit South Carolina each winter, descending with their high-pitched cries into the wetlands of the ACE Basin.
We catch just the briefest glimpses into the lives of the creatures around us. Few of us know much about the nesting behavior of even the most common birds. We have only a general idea of their diets or the perils they face when it comes to predators, parasites and plain old competition.
That reality is compounded for those animals that spend only part of the year in the state, and with some of those, what we don't see is completely foreign. That is certainly the case with the tundra swan. A few hundred visit South Carolina each winter, descending with their high-pitched cries into the wetlands of the ACE Basin, primarily near the S.C. Department of Natural Resources' Bear Island Wildlife Management Area. They forage in groups, dining on underwater plants, and spend nights on the water, out of reach of potential predators.
That they winter at all in South Carolina may be due primarily to one man. According to DNR wildlife biologist Dean Harrigal, in the 1970s, landowner Allen Spaulding, hoping to establish Canada geese on his Poco Sabo plantation, brought some in from the western U.S. (Current federal regulations require a U.S. Fish and Wildlife Service permit to transfer migratory waterfowl reared in captivity.) The following spring, they flew north, and from then on, Poco Sabo did indeed have wintering migratory Canada geese. What happened next was remarkable.
"He told me," says Harrigal, "that one day a handful of tundra swans showed up with his Canada geese. They came to his twenty-eight-acre pond, and eventually others came with them and their numbers grew."
Birders were ecstatic.
"People came from miles around to see that early flock," says Harrigal, "and they still come to see and photograph them now. They're pretty spectacular creatures."
Tundra Swan - Cygnus columbianus
Description: Average four to five feet long, with six- to seven-foot wingspans. White, with black bills and feet. Yellow spot at the base of the bill is important in distinguishing them from the larger trumpeter swan. Mute swans have an orange bill with knob and black base.
Range and Habitat: Breeds in the Arctic, across northern Alaska and Canada. Winters on the West Coast and on the East Coast from New Jersey to South Carolina.
Reproduction: Tundra swans mate for life. Grass nests are built near water. Three to five eggs, which hatch in thirty days. Young fledge in sixty days
Viewing Tips: In South Carolina, visit Bear Island Wildlife Management Area from mid-February to early March (Bear Island is closed from November 1 to February 7). Early morning is the best viewing time.
These days, Bear Island is the most accessible viewing area for tundra swans in the state, although the appromimately 300 descendants of the flock that numbered 128 in 1986 now "flip-flop back and forth between public and private property around the ACE," says Harrrigal.
The ACE Basin swans are just a tiny fraction of the approximately 100,000 tundra swans that migrate from northern Alaska and Canada to the East Coast each year, settling for the winter from New Jersey southward. Approximately 70,000 make it as far as North Carolina. Another group, from western Alaska, winters on the West Coast.
Once called whistling swans - for the sound made by their wings rather than for their call - these are the smallest of the northern hemisphere swans, although they are impressive nonetheless, four to five feet long, with six- to seven-foot wingspans. Males and females - cobs and pens, officially - look alike, although the females are a little smaller than the males, which weigh about sixteen pounds. Both are white with black feet and have black bills with a yellow spot at the base. Immature tundra swans have some grey coloring, mainly on the head and neck, and pinkish-grey bills, but they are in full adult plumage by their second winter.
Tundra swans mate for life, which can be twenty years or more. Much of their reproductive process - courting, mating, nesting and raising young - takes place on the seemingly sparse landscape that gives them their name. Those in South Carolina and along the rest of the East Coast head north in March and reach their breeding grounds in mid-May.
The tundra is a land where low temperatures, frozen subsoil and short growing seasons preclude the growth of trees but allow for moss, lichens, grasses and hundreds of species of flowers. Frozen subsoil known as permafrost keeps meltwater at the surface, so in spring and summer these marshy plains are richly dotted with small lakes and streams. There is little precipitation - about ten inches a year - but there is also little evaporation. Daytime highs may hit the 50s in summer, with occasional frost possible even then.
Animal life found there includes four dozen species of mammals, from shrews to caribou, a few fish and plenty of insects. More than one hundred species of birds, including loons, falcons, geese, gulls and terns, make their way to and from the Arctic each year to feast on the plants and animals in this wet, nutrient-rich land. Tundra swans feed on marsh plants, pulling leaves, seeds, stems and tubers from under the water, submerging their long necks and sometimes tipping up - a behavior that often causes their heads and necks to be stained a rusty color.
These are highly territorial birds that will aggressively defend the nesting areas where they use grass and vegetation to build mound-shaped nests near open water. They are formidable when agitated, and it's thought that egg predation from other species, including gulls, jaegers, otters and skunks, has little real impact on their numbers.
The female lays three to five eggs, and both she and her mate watch for danger and defend the nest for the thirty days it takes the eggs to hatch. Cygnets, as young swans are called, grow quickly, fledging in a little more than two months. By late September, adults and young - and sometimes young from earlier years - gather in the last open water for the long, cross-continental journey, flying at altitudes of 2,000 to 5,000 feet for up to 4,000 miles.
Most of these birds used to winter in the Chesapeake Bay, but by the 1980s, their distribution had shifted to the south. Hypotheses for this change include declines in aquatic vegetation and competition from mute swans and Canada geese. In North Carolina, they are often found in farmers' fields, eating leftover grains.
When they arrive, says Harrigal, "they break off in family groups and congregate at food sources. They can take a lot off the table pretty quickly, and then they've got to go somewhere else." They roost in flocks.
"Very seldom will you see them show up before the 10th of November, and they're gone by early March," adds Harrigal. "But to have this impressive bird in our state where people can see them for any amount of time is a real thrill."