Associated Press
BELLINGHAM — Researchers are hoping this may be the season they locate the source of poisonous lead shot that is killing a record number of trumpeter swans.
The lead shot blocks the swans’ airways and digestive systems, finally entering their bloodstream and causing the onset of a progressive paralysis.
Hundreds of the swans have died in the past three winters in Whatcom County. Lead shot rests on the beds of lakes and ponds in the birds’ northwest Washington wintering grounds.
Earlier this week, 13 trumpeter swans were near death on the banks of Wiser Lake.
"It’s one of the most miserable ways to die," said Mike Davison, a wildlife biologist for the state Department of Fish and Wildlife. "For all intents and purposes, these are dead birds. This isn’t where they want to be. If they stay here, it’s a foregone conclusion that they are candidates for the freezer."
Dead birds are preserved in freezers so their deaths can be investigated. Volunteers with Fish and Wildlife, Pilchuck Valley Wildlife on Camano Island and the North Cascades Audubon Society are trying to figure out where the swans are picking up such massive amounts of lead.
The lead shot likely was deposited over time by hunters before lead shot became illegal for waterfowl hunting in Western Washington in 1988 and nationally in 1991.
The lead has killed 138 trumpeter swans already this winter, as well as several tundra swans. Last year, 159 died in the October-February period the swans spend here.
Davison calls it a "nuclear" die-off.
Swans are particularly vulnerable to lead shot because of their long necks, which can crane down to depths most waterfowl can’t reach.
When they search for food, the swans use their necks to feed deep in the sediment of ponds. They look for seeds and grit, which they filter out their bills. They store sediment in their gizzard to help grind down the food entering their system. Lead in the gizzard causes the swan’s system to back up and prevents food from moving through. The gizzard grinds the lead pellets until the swans become poisoned.
Trumpeters come to northwest Washington from Alaska for the winter. Researchers began documenting the swans when they began showing up in Whatcom County in October, keeping track of where they feed and live.
Twenty-five birds in Whatcom County and Canada have been fitted with radio collars so Fish and Wildlife scientists can track them and find them every few days. State workers counted 1,432 trumpeter and tundra swans on Tuesday.
Volunteers with the Audubon Society counted the swans twice a week for six weeks in October and November.
"Anytime we see some natural beauty like swans being decimated, especially since this is something we humans are doing, we should be concerned," said volunteer Joe Meche, a member of the North Cascades Audubon Society. "We’re interrupting a natural cycle and we need a solution."
Trumpeter swans become poisoned from lead shot in their wintering areas throughout the northern United States and Canada. The number of deaths, however, is far greater in Whatcom County.
"It takes a lot of lead to explain the volumes we’re finding in these birds," Davison said.
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