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The deadly foam that

has subsided and several hundred birds rescued from the slime are being released. But the death toll worries conservationists.

More than 10,000 scoters, or seaducks, were killed by the first onslaught of algal foam that hit the Olympic Peninsula in mid-September, said

, marine biologist and seabird specialist at the University of Washington.

That toll -- mostly surf scoters and white-winged scoters -- amounts to 5 percent to 7 percent of their overall numbers on the West Coast, she said.

"That is a pretty significant bite into those species," Parrish said. "I don't think it will knock the population back for years. But at least with surf scoters -- a species that's in decline -- conservation scientists are rather concerned about it."

Parrish estimated that thousands more seabirds, including many red-throated loons, were killed in the second wave of foam off the Long Beach Peninsula about two weeks ago.

The foam was linked to the bloom of a single-cell phytoplankton, or algae, called Akashiwo sanguinea, that hasn't posed a problem in the Northwest -- until now.

. But they suspect that a combination of warm water and low salinity fueled a reproductive frenzy. Winds blew the bloom towards shore where it was whipped by the surf into sticky foam which stripped vital waterproofing from the seabirds.

Not all the birds died of hypothermia, however. In fact, about 200 have been released this week by the

north of San Francisco.

"To see them released and returned to the wild is a wonderful feeling for all the volunteers who've worked so hard to make this happen," said Paul Kelway, spokesman for the center.

The facility, which usually rescues birds from oil spills, took 450 seabirds off the hands of the

near Astoria, which was overwhelmed with birds from the Long Beach Peninsula.

Almost 100 went to

north of Seattle and another 75 stayed at the facility near Astoria.

"We kept the worst of the birds because they wouldn't have made it through the trip," said Sharnelle Fee, director of the Wildlife Center of the North Coast.

Rehabilitating the seabirds has been a multi-step process involving more than 100 volunteers at the three centers.

Initially, they were given warm fluids and food. Once they gained strength and were stabilized, they were washed in tubs of warm, soapy water.

That step lasts only about 15 minutes, Kelway said.

"The washing process is very stressful for them," he said. "Many of these birds haven't seen a human being before so it has to be thorough and quick."

Once clean, the birds are put in plastic cages with netting on the bottom, giving them a soft surface not unlike the ocean. Built to live at sea their whole lives, they develop sores and other injuries when forced to stand on hard surfaces.

To dry them, the cages are suspended under pet dryers that circulate warm air.

The birds are then placed in preening pools to finish their rehabilitation.

The Bay Area center could free more birds next week, and the center near Astoria could stage releases as well. But everything depends on the weather.

The foam has subsided and a big bloom was pushed into the Strait of Juan de Fuca, Parrish said.

"I'm not getting any information about (the algae) planning another attack, Parrish said. "But if there is a storm surge, we're going to get more foam and birds could be trapped."