What’s Killing Seabirds?
Kathleen Wolgemuth has long walked the beaches along Ocean Shores, Washington and has admired the Brandt’s cormorants she sees swooping overhead. So when she spotted the feathery blob on the beach last May, she was excited—a dead Brandt’s cormorant, up close for the first time. She thought them handsome: big brown birds, bodies as long as a yardstick and wings a foot wider than that.
Then she trudged a little farther. And saw another dead cormorant. Her excitement turned to dread.
“I kept walking and I found a third one. I thought: “Man, this is very strange,”” says the volunteer bird surveyor. “I”m used to seeing them – but alive. Not dead. To me, it’s a chilling thing that’s going on.”
The sentiment is shared by many who keep watch on the seabirds and marine creatures of the Pacific coast. During the summer of 2005, some saw baby birds starve to death where they normally thrive. Some saw eggs abandoned by bird parents who seemed to know something about the environment that scientists themselves did not comprehend. Perhaps more than 100,000 seabirds of various species washed up on Pacific beaches from central California to British Columbia.
“They were piling up at a time of year—spring and early summer—when generally aquatic birds like seabirds and marine mammals should be at their peak [condition],” says Julia Parrish, a University of Washington biologist who directs the bird-survey program for which Wolgemuth volunteers: the Coastal Observation and Seabird Survey Team. “What was alarming to us was two things—first the sheer numbers, second the time of year.”
It’s not just birds, either. Last summer saw a 35 to 45 percent drop in juvenile salmon surveyed off the coasts of Oregon, Washington and Canada’s British Columbia, as compared with federal surveys for the previous six years. That drop “is bizarre to me,” says Ed Casillas, Estuarine and Ocean Ecology program manager at the National Oceanic and Atmospheric Administration (NOAA) in Seattle.
Even lower on the food chain, tiny plankton plummeted; off Oregon, zooplankton numbers fell 75 percent in June as waters for several weeks rose five to seven degrees higher than usual before returning to normal.
Scientists wonder: What happened? Will this coming spring and summer bring more surprises? This string of oddities has them questioning whether something basic has gone wrong in the natural world or whether they’re seeing a fluke. Many are comparing notes and attending meetings with scientists across disciplines.
What we do know is something weird happened with the weather last summer. And many scientists blame the bird deaths on a lack of food. They couldn’t find adequate food during the crucial breeding period; long afterward, food rebounded (in some cases), but by then it was too late. Noisy, squawking auklets, for example, got an ominous start to the breeding season by nesting in far fewer boxes than usual—120 instead of at least 400—on the Farallon Islands off San Francisco. To the astonishment of researchers, the birds en masse abandoned their eggs by mid-June, leaving their progeny to die.
An abandonment on that scale is something “we have never observed before there, as the number of babies born totaled zero, zilch, nada,” says Bill Sydeman, director of marine ecology for the Point Reyes Bird Observatory.
“We don’t understand why. We know that the auklets eat krill,” he says, “and they eat a lot of it”—as much as 80 percent of their diet. Researchers surmise that the available krill had plunged.
Which prompts the question: Why did krill drop in May? Krill eat even smaller things called diatoms. Researchers think their numbers had fallen, too. By going backward further, step by step, ultimately one trigger stands out. Sydeman calls his favored culprit “the anomalous winds in May.”
Southwesterly winds—not the normal northerly winds—flowed through western coastal areas last May, the effect of which is something like slamming the door shut at an all-you-can-eat smorgasbord. Normally, at this crucial time of year when seabirds are ready to breed and salmon have reached the Pacific Ocean ready for big meals, northerly winds push deep, cold ocean waters—and their resident krill and plankton—to the surface, making them easy pickings. This year, this “upwelling” came late, in July.
“The birds were dead and the salmon were dead by then,” says Bill Peterson, a NOAA oceanographer in Newport, Oregon. Perhaps only twice in 50 years has upwelling arrived late. “This is the latest it’s ever been.”
“It all starts with the wind. If the wind isn’t there,” Peterson adds, “then we’ve got problems.”
Peterson organized a January 2006 meeting of scientists to explore what went wrong. Why did the northerly winds arrive late? What was the atmosphere doing to cause that? Ideally, they’d like to piece together warning signs to help predict any future repeats. It’s not the only such meeting: Alarmed by a 47 percent decline in marine birds in Washington’s Puget Sound since the 1970s, the nonprofit SeaDoc Society in September also convened regional scientists. The society pledged to finance three studies, including one on the impact of forage-fish availability on marine-bird decline.
Global warming so far isn’t blamed by scientists, though Peterson wonders: Is this what life with global warming will be like? The odd summer of 2005 must be repeated “something like 10 of the next 20 years” to “lend more weight to the notion that something has changed in coastal climate and that it may be linked to global warming,” says Nate Mantua, a research scientist with University of Washington’s Climate Impacts Group.
“Global warming always hovers as a backdrop, but most people are looking for the exact mechanism, and “global warming” is just too broad,” Sydeman adds.
For now, Wolgemuth will be anxious to see what happens when spring approaches and it’s time for her to comb the beaches of Ocean Shores in a hunt for dead seabirds. She’s not the only one awaiting scientists” solution to the puzzle of 2005.
“I guess we’re just anxious to see what they find out,” says Dave Sones, vice chair of the Makah Tribal Council, whose tribe owns Tatoosh Island at the extreme northwestern tip of the U.S. Only 35 percent of the island’s breeding pairs of common murres produced a chick this year, down from the typical 85 to 90 percent.
“There were a lot more chick deaths than ever before, which is difficult to watch,” says Parrish, the biologist who monitors the Tatoosh murre colony. “It’s very difficult to watch anything die—especially if they’re dying slowly…I think most people would want to lend a helping hand.” But, as a scientist, she must remind herself that her role isn’t to save organisms. “Even if death is horrific, your job is to report accurately and sleuth out the factors that are creating this change. You have to grit your teeth a lot.”