Scores of wild mallards have been found dead or dying this week along widely separated stretches of the Los Angeles River near Glendale and in Long Beach, apparently victims of an outbreak of botulism aggravated by the drought, wildlife officials said Friday.
Los Angeles animal regulation officers picked up about 30 dead ducks Friday on the concrete banks of the river along the Golden State Freeway near Griffith Park. State fish and game officials found another 30 to 40 in percolation ponds near the Long Beach and San Diego freeways.
Several ailing ducks, too weak to walk, were captured for treatment and examination.
Although water in the river was tested for poisons, officials said they suspect the birds were hit by a mild outbreak of botulism, a type of bacterial poisoning that thrives in warm, wet environments.
This form of the bacteria can be transferred easily among ducks, but does not usually affect humans or other animals.
“It’s pretty much a duck thing,” said Earl Lauppe, a wildlife management supervisor for the Department of Fish and Game.
The deaths, which began about a week ago, worried residents along the river who feared the water may have been contaminated.
But Irwin Biederman, a hazardous materials specialist for the county Department of Health Services, said he doubted chemical contamination killed the birds because other animals along the river were unaffected.
And officials investigating the Glendale-area deaths ruled out a virus because it would most likely have affected a wider area.
Lauppe said botulism outbreaks are relatively common among ducks in warm weather, and generally are restricted to isolated areas because the bacteria concentrate in standing water.
But wildlife experts said it is important to remove dead ducks quickly so they do not infect other birds migrating south this fall.
Michael Burns, supervisor for the northeastern area for the Los Angeles Department of Animal Regulation, said the drought may have played a role by shrinking water holes, forcing large numbers of ducks to share smaller pools of water.
Ten ailing ducks were taken to the Glendale Humane Society’s shelter Wednesday and Thursday by society workers.
Two of the birds died, but the rest were released Friday to the Pacific Wildlife Project in Laguna Niguel after they appeared to be recovering.
“They seemed to be coming along quite well,” state humane officer Joseph Sykora said. “They were beginning to preen themselves and that’s always a good sign.”
About 30 ducks were found dead Friday between Riverside Drive in Glendale and Los Feliz Blvd. in Atwater Village.