Hundreds of tundra swans suddenly rose off of a marsh, the strokes of their powerful wings making a whistling sound as they flew.
They landed a short distance away at another marsh, where other tundra swans were gliding over the water like a flotilla of toy sailboats.
Mike Schlepp doesn’t know what triggers the swans’ abrupt change of location, but he observes the flights of the showy birds daily. About 3,000 migrating swans are using the wetlands on his farm south of Rose Lake, Idaho.
Schlepp and U.S. Fish and Wildlife officials couldn’t be happier. This is the first year they’ve counted large numbers of tundra swans on the farm, where nearly 400 acres of clean-feeding areas were established in 2007 through a conservation easement.
Migrating swans stop to feed at marshes along the Coeur d’Alene River en route to breeding grounds in Alaska. But most of the river’s wetlands are contaminated with mine waste, putting the swans at risk of death from lead poisoning. About 150 swan carcasses are found each year in the marshes.
Before this year, the highest number of tundra swans using the safe feeding grounds at the Schlepp farm was 221. But on Saturday, swans started arriving en masse, lured in by 32 decoys that Schlepp set out.
“The sky was filled with swans, one wave after another,” he said. “It was a tremendous sight.”
So far, wildlife officials have counted about 3,200 tundra swans in the Coeur d’Alene Basin, said Toni Davidson, a U.S. Fish and Wildlife biologist who manages the Schlepp project. That means that nearly all of them are on clean feeding grounds, she said.
High water in other marshes from recent flooding helped steer the birds to Schlepp’s property, Davidson said. The farm gets its water from two creeks. Through a dike system, water levels can be kept at 2 feet or less. That’s ideal for the swans, which use their long necks to root for tubers and seeds in the mud.
Habitat improvements also helped. Last year, the U.S. Fish and Wildlife Service hired Ducks Unlimited to build shallow islands in the marshes and plant buckwheat and other seed-bearing grasses that the swans eat. This was also the first year decoys were set out.
“I think all three things worked together to make a difference,” Schlepp said.
Tundra swans symbolize the toll that historic mine waste still takes on local wildlife. Over the past century, about 100 million tons of mining waste from Idaho’s Silver Valley washed into the Coeur d’Alene River system. Swans are particularly vulnerable to lead poisoning because they swallow so much mud with their food, said Tim Kaiser, an environmental contaminants specialist.
Federal officials want to expand safe feeding areas for waterfowl. A cleanup plan for the Coeur d’Alene Basin recommends converting 1,500 acres of farmlands to clean wetlands for wildlife.
Money from legal settlements with mining companies pays for the operation of waterfowl feeding grounds on the Schlepp property. Last year, the Coeur d’Alene Basin Natural Resource Trustees, which administers the settlement money, spent about $220,000 on the project, including the habitat improvements.
The number of tundra swans in the Coeur d’Alene Basin will peak this month. Then, they’ll be heading north to Yukon Delta.
The graceful swans are a boisterous lot, calling all hours of the day and night. The noise from Schlepp’s marshes sounds like the muffled roar of cheering from a distant stadium.
“It’s the sound of success,” Davidson said. “Happy birds. Food, food, food.”
Since tundra swans return to the same areas along the migration route, they should come back to the Schlepp property next year, Davidson said.
“To me, it sounds like spring,” Schlepp said of the swans’ clamor.