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Spokane, Washington  Est. May 19, 1883

Coeur D’Alene River Swans Dying At High Rate Flooding At Migration Stop May Have Contributed To Lead Poisoning This Year, Biologist Reports

An unusually large number of swans died last month along the Coeur d’Alene River during a stopover on their winter migration south.

The cause of death for many is the usual suspect - lead poisoning.

“Flooding could be part of the story,” said Dan Audet, a biologist with the U.S. Fish and Wildlife Service.

Since 1992, the agency has been closely tracking waterfowl deaths in the chain lakes region to gather information about the extent of heavy metal pollution there.

The shallow lakes act as a settling pond for sediment being washed downstream from the Silver Valley, the home of the Bunker Hill Superfund site and several smaller sites polluted by decades of mining.

In December, the agency found 10 dead swans and one dead goose. Nine swans were sent to the National Wildlife Health Center laboratory in Madison, Wis. All nine were found to have lead in them, and six so far have been confirmed to have died from lead poisoning. The results on the others are not final.

That’s the most lead-poisoned birds the agency has ever collected in December, Audet said. Four more dead swans have been picked up this month.

The dead swans were found in the slough near Harrison, in Thompson Lake, and one was found in Carlin Bay on Lake Coeur d’Alene.

Last February, floodwaters carried thousands of tons of metals-laced sediment downstream to Harrison. In one day alone, the flood carried twice the amount of lead past Harrison than in all of 1993, and eight times that in 1994, according to measurements by the U.S. Geological Survey.

The flooding not only dumped fresh sediment in the lower lakes area, but also may have stirred up the sediment already there, Audet said.

His agency plans on taking new samples of the lower lakes this spring to see if the concentration of metals has changed.

Birds ingest lead while feeding on tubers and other aquatic vegetation in the wetlands.

It can take one day to get sick, and three weeks to die, Audet said. “We have no idea the total number of birds that die,” he said.

Humans also are exposed to metals in the area, but to a much lesser extent.

Most recreation sites from Cataldo to Harrison have signs warning people not to eat large amounts of fish, waterfowl or aquatic plants. The signs also advise people to wash their hands before eating or serving food.

The discovery of lead-poisoned waterfowl in the Coeur d’Alene Basin is not new. Reports of poisoned birds go back to the 1930s.

Audubon Society members out on their annual Christmas bird count expect to see at least one swan, said Susan Weller, an Audubon board member.

“You know you’ll get at least one, because it’s the leaded one that’s left behind,” she said. “I’ve seen ones that are in the throes of dying.”

Weller and Audet also expressed concern that bald eagles are ingesting lead, because they’ve been seen scavenging the carcasses of poisoned waterfowl.

The dying swans have attained national attention since the federal government and the tribe sued mining companies over the cleanup of the basin last year.

“If a bird can come in for two weeks and be dead, you have serious lead pollution,” said Bob Bostwick, Coeur d’Alene Tribe press secretary.

Holly Houston, a spokeswoman for local mining companies, said it’s important to remember that thousands of swans and geese pass through the area without succumbing to lead-poisoning.

“One of the objectives that we had …was to come up with solutions or ways to develop other habitat and other feeding areas,” Houston said. “We had a million (dollars) set aside to study the issue and see what can be done to alleviate the problems.

“The problem is, during litigation right now, all these ideas of cleanup plans are on hold until we can get something negotiated with the government and the tribe.”

Audet is moving ahead with his research, part of which maps where the heavy metals are and where the swans typically feed. The agency also is conducting laboratory tests to see how much lead swans can tolerate, and exploring ways to improve the habitat without moving dirt.

“Certain vegetation may help reduce exposure to lead or help birds stave off the effects of lead,” he said.

But until something is done, he said, “there’s no reason to suspect it’s going to change.”

, DataTimes ILLUSTRATION: Color photo

MEMO: IDAHO HEADLINE: CdA River swans die at high rate

IDAHO HEADLINE: CdA River swans die at high rate