A toxic chemical produced by algae has been detected in some sick California brown pelicans that are being found in record numbers along the West Coast, though researchers don't believe it's the primary cause of their widespread illness, wildlife experts said.
Three of six blood samples taken from sick pelicans tested positive for domoic acid, according to preliminary laboratory results from the University of Southern California.
Five of 14 water samples taken from waters off the Southern California coast also indicated low concentrations of domoic acid in the phytoplankton.
"We believe these results are significant but do not explain all the signs we are seeing in the pelicans," said Dr. Heather Nevill, a veterinarian at the International Bird Rescue Research Center, which provided the samples.
"We are seeing a number of conditions that are not typical of domoic acid toxicity or a domoic acid event."
Most of the hundreds of ailing pelicans are thin, but birds poisoned by domoic acid are typically of good body weight.
That leads researchers to believe that domoic acid is likely playing a secondary role to a larger problem.
Domoic acid, a neurotoxin, is produced by microscopic algae.
Birds and sea mammals ingest the acid by eating fish and shellfish that consume the algae.
Jay Holcomb, executive director of the Fairfield-based center, said two of the pelican samples showed relatively high levels of domoic acid and one was relatively mild.
The center said additional blood and tissue samples are being tested and more information is anticipated within the next two weeks.
Sick, disoriented pelicans have been found in unusual places far from their homes on roads, farm fields, alleys and backyards.In the last week, the birds have been reported staggering across Culver Boulevard in Playa del Rey and on a Los Angeles International Airport runway.
One bird was reported to have struck a vehicle.
The center said it has recorded 265 reports of dead or ailing pelicans from Baja California, Mexico, to Washington state.
More than 100 pelicans are being nursed back to health at the center's two facilities in Fairfield and San Pedro, with a combination of intravenous fluids, medications and a diet of smelt and squid.
The California brown pelican is a subspecies of the common brown pelican.
Its habitat stretches from the Sinaloa and Nayarit coast of Mexico to the Channel Islands off the Southern California coast.
Brown pelicans nearly became extinct in the 1960s and 1970s because the pesticide DDT infiltrated their food in nesting grounds such as Southern California's Anacapa Island.
The species started to recover in 1972 when DDT was banned in the United States.
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