Tracking a Serial Killer : For the Second Time in Two Years, Grebes at the Salton Sea Are Dying Mysteriously, and Scientists Are Seeking Clues
Biologists and bird lovers are helplessly witnessing Act II of one of the state’s biggest environmental mysteries of recent years: What is killing the eared grebes of the Salton Sea?
Upward of 700 of the small migratory birds have been found dead in the past week on the shores of the Salton Sea, California’s largest and most polluted body of water.
Two years ago at this time of year, the carcasses of 150,000 grebes were recovered over several weeks and scientists were never able to pinpoint a cause for the deaths.
“It’s the same bird and the same mystery,” Clark Bloom, manager of the Salton Sea National Wildlife Refuge, said Friday. Wildlife biologists have been scooping up the lifeless forms by the shovelful and sending samples to the National Wildlife Health and Research Center in Madison, Wis.
A scientific strike team of veterinarians, pathologists and infection specialists, backed by bird specialists from Sea World in San Diego and San Diego State University, is determined to break the case this time.
“We’re hopeful that we can use what we learned last time as a starting point and finally find an answer,” said Lynn Creekmore, a veterinarian with the research laboratory, which is run by the U.S. Fish and Wildlife Service.
Creekmore said the investigation is centering on three possible culprits: biotoxins such as algae or plankton, contaminants such as heavy metals or pesticides, and avian cholera. Botulism has been ruled out after initial tests.
The stakes of the case range beyond just providing answers to the whodunit aspects of what biologists call a “significant die-off.”
If the birds are found to have died because of something in the Salton Sea, it could prove to be a grim turning point in the sea’s environmental misfortunes. The Salton Sea, 35 miles long and 15 miles wide, serves as an agricultural sump for Imperial County and a depository for the fetid New River from Mexico.
Smelly in summer and an ominous chocolate color all year round, the sea has experienced a drastic decline in tourism and recreation in the past decade, leaving campgrounds nearly empty and marinas and motels bankrupt. Signs posted here warn people to eat only limited quantities of Salton Sea fish.
Beyond the economic impact, any indication that the sea is killing grebes could also limit its future as part of the Pacific Flyway.
The grebes are among dozens of species that use the Salton Sea and its marshes as a stopover on their way from their winter roosting spots around the Sea of Cortez to their nesting spots in Northern California and the Pacific Northwest.
Two years ago, the dead birds were found to have elevated levels of selenium, arsenic, mercury, zinc and chromium, possibly from agricultural pesticides that drain into the Salton Sea. Still, scientists decided that the heavy metals were not concentrated enough to cause death.
Although the possibility that the Salton Sea killed the birds is being considered, there is a chance that the birds died because of something they consumed at their winter home on the Sea of Cortez, or that such die-offs are acts of nature.
“It could be that there have always been die-offs but they just occurred in remote areas and we weren’t aware of them,” said Susan Saul, spokeswoman for the Fish and Wildlife Service regional office in Portland.
One estimate puts the current number of grebes at Salton Sea at 400,000.
Whatever is killing the birds is also apparently driving them mad in the process. Bizarre, un-grebe-like behavior is being spotted among grebes on the Salton Sea.
“Finding grebes onshore is very unusual,” said refuge biologist Mary Hunnicutt. “They’re picking at their feathers and actually pulling them out. That’s not normal.”
