Tundra swans en route to winter home on Chesapeake
The Arctic coastal plain provides breeding grounds for more than 100 species of migratory birds, the largest of these being the tundra swan. In sharp contrast with their surroundings, tundra swans are completely white except for their black bills, eyes and feet. These majestic birds average 14–16 pounds with wingspans of 6–7 feet.
As their name suggests, these swans begin their lives on the tundra. In mid-May, adult swans arrive on the lush tundra of the Arctic coastal plain, which includes part of the Arctic National Wildlife Refuge on Alaska’s northern coast. Tundra swans mate for life, which in some cases may be 20 years or more.
The birds begin nest building, pulling rotting vegetation into mounds. Pairs may often reuse old nests from previous years. Nests are placed on islands or on the edges of lakes or ponds. Swans will lay 3–6 eggs and both birds tend the eggs, with the female incubating them about 70 percent of the time. Incubation lasts 31–33 days.
Young swans, or cygnets, are precocial. This means they are born with down and can follow their parents and begin to find their own food. Adults may stir up submerged aquatic vegetation for the young to feed on. After the first week or two, the families often graze on the tundra for short periods.
Although tundra swans depend on these northern areas to breed, they are equally dependent on southern areas to survive the winter.
The Chesapeake Bay is one of the most important wintering areas for a variety of waterfowl, including tundra swans, as well as Canada geese and a variety of ducks.
We may not see any migrating tundra swans yet, but they have been on the move since late September. As soon as the young can fly, families of swans began leaving their Arctic breeding grounds.
This first migration will teach the cygnets their migration routes and stopovers sites to reach wintering grounds along the Pacific and Atlantic coasts, with the Chesapeake Bay being the final destination for many of the birds.
About 75,000–95,000 tundra swans winter from southern New Jersey south to North Carolina. The eastern wintering population of tundras travel an incredible 3,500–4,200 miles from Alaska and the Arctic to the East Coast, flying both day and night. The normal altitude during migration is 2,000–4,500 feet with a maximum sustained flight speed of 51 miles per hour.
Their stops are infrequent and the swans must continue to move south as their feeding grounds freeze. They fly in V-formations or lines with a wing beat that is slow and steady. A high-pitched, mellow “hoo-hoo” call of the tundra swan is often heard before the flock can be seen.
Tundra swans begin arriving on the Chesapeake in November with numbers increasing and finally peaking in January. They will remain on the Chesapeake and other East Coast sites throughout the winter.
Historically, their favorite foods have been submerged aquatic vegetation, emergent vegetation, clams and other mollusks. Because of the loss of submerged aquatic vegetation, some swans, like geese, have changed their diet to include waste grains in farm fields. Others have simply moved to new wintering areas. For example, more than half of eastern tundra swan population now winters in North Carolina.
Spring migration follows the retreating ice and snow. Most tundra swans will leave the Chesapeake by mid-March to migrate back to the Arctic coastal plain. The birds leave the wintering grounds at their lowest weight and will stop more frequently during their northward migration.
When we see a bird or fish or other wildlife, we often think of them as “belonging” to us, to where we live or where we have seen them. We forget that many of “our” wildlife species are really travelers, constantly moving with the seasons, sometimes to places very far and very different from our homes. They may use one type of habitat and rely on one type of food during the spring breeding season but require a different habitat to survive the winter.
So it is often not enough to just provide for the needs of wildlife when they are here at home. In order for these migratory species to survive, they must have food and shelter during their travels and at their many destinations. If you enjoy swans or geese, eels or shad, warblers or hawks or even monarch butterflies, find out where they spend their “other” lives. Chances are there are ways to help protect them here as well as across the country or in other lands.
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Kathryn Reshetiloff is with the U.S. Fish and Wildlife Service’s Chesapeake Bay Field Office in Annapolis.
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