Swan die-off attributed to ingestion of lead shot

The number of swans deaths attributed to ingestion of lead shot has nearly doubled in the past 15 months, to 1,850 in Whatcom County and British Columbia.

Between 1998 and January 2004, about 1,000 swans were found dead in that region.

Scientists are studying the deaths and the source of the lead pellets that contributed to the die-off over the past six years.

It’s the largest swan die-off from lead poisoning anywhere in North America, according to The Trumpeter Swan Society, a group based in Maple Plain, Minn., with 470 members in the United States and Canada.

Necropsies on swans — with an emphasis on lead poisoning — began at Western Washington University on Saturday and will continue through Thursday by U.S. Fish and Wildlife Service toxicology specialist Cindy Schexnider and state Department of Fish and Wildlife biologist Mike Smith.

The use of lead shot in waterfowl hunting was banned in 1991, but accumulations remain in farm fields and wetlands from the previous decades of use. Trumpeter swans ingest the pellets when they pick up gravel from the bottom of wetlands to help grind food in their gizzards.

Until about 10 years ago, trumpeter swans rarely wintered in Whatcom County. Their numbers grew from between 10 and 200 in the early 1990s to more than 1,000 today.

Two factors — an end to hunting the birds and a change in feeding patterns from nearshore areas and estuaries to farm fields — spurred the swans’ comeback, according to the Canadian Wildlife Service in Vancouver, British Columbia.

Scientists leading the study at Western are seeking volunteers to help set up the lab and record results of necropsies.

Since last fall, The Trumpeter Swan Society has collected about $7,000 in donations through an adopt-a-swan program, said Martha Jordan, volunteer coordinator of the organization’s Washington chapter.

The goal, she said, is to raise $15,000 to $20,000 more to help pay for radio transmitters, other equipment and necroscopies.

Fishermen who use lead sinkers also are under scrutiny for the impact they have on waterfowl. Washington’s fragile population of nesting loons lost at least one nesting adult last year in Eastern Washington at Omak Lake. An autopsy revealed a lead sinker in the fish-eating bird’s gizzard.