Earlier this year, an impressive number of birds died near the mouth of the Santa Ana River. The cause of the deaths was never discovered. Today, the San Francisco Chronicle reports that seabirds all along the West Coast have been dying in exceptionally large numbers.
This is the third year that scientists have found unusually large numbers of marine birds — mainly common murres, but also rhinoceros auklets and tufted puffins — washed up on beaches in California, Oregon and Washington. In 2005, the first year of the phenomenon, large numbers of Cassin's auklets also died.
Hannah Nevins, the coordinator for Moss Landing Marine Laboratories beach survey program, said 253 dead murres were recovered on 11 Monterey Bay beaches during the first week of March. During the past nine years, an average of nine dead birds were collected on the same beaches during the same week, she said.
Unlike what happened in OC, the cause of these deaths is readily apparent.
Most of the casualties were young birds that had just gone through their first winter.
“They were all in poor condition, and generally had empty stomachs,” [Nevins] said. “Either they were not finding food, or they were unable to capture the food they did find.”
But what is causing the starvation conditions is less clear. It “appears to be linked to changes in the California Current — a vast oceanic stream that delivers cold, nutrient-rich water from the Gulf of Alaska to the continental West Coast.”
Yet Howard Freeland, a research scientist with the Institute of Ocean Sciences in Sidney, British Columbia, said the California Current generally has remained strong during the past two years, though he said there have been some fluctuations.
But Julia Parrish, an associate professor in the school of aquatic and fisheries science at the University of Washington, said the North Pacific Ocean appears to be in major flux. During the past two years, she said, offshore upwelling did not begin off the continental Pacific Coast until summer, two months later than usual.
That was bad news for the birds because the warm water provided them little food during the height of the breeding season, Parrish said.
The once generally predictable North Pacific currents, she said, are “swinging like a pendulum.” For example, in summer 2006, an unexpected “super upwelling” happened off the Oregon coast, sucking in vast quantities of abyssal water that was so low in oxygen that a temporary dead zone formed along the coast.
There are some suspicions that these changes are tied to global warming, but no one is willing to definitively state there is a connection. Still, some things are easier to see.
“What's clear is that during the past decade, there's much more variability out there than there was during the preceding 40 years,” [Bill Sydeman, the director of marine ecology at PRBO Conservation Science] said.
“That probably causes some disability in the ecosystem to recover from human-caused impacts such as pollution, coastal development and fishing,” he said.
Meanwhile, in better news for twitchers, the Los Angeles Times reports that two bald eagle chicks have hatched on Catalina, becoming “the first to successfully hatch there in more than 50 years without human help.”
Catalina Island's bald eagles hadn't been able to produce chicks on their own because the pesticide DDT had built up in their bodies and thinned their eggs. A large deposit of the pesticide, banned in the United States in 1972, remains on the ocean floor off Palos Verdes Peninsula and continues to seep into fish and other marine life.
Maybe in 50 more years, the fish around Catalina will have good news about overcoming the effects of DDT, too.
