Washington Weather May Be Killing Seabirds
NEAH BAY, Wash. — The mass starvation deaths of murres on Tatoosh Island off the Olympic Peninsula may be due in part to unusual weather patterns along the West Coast, scientists say.
Last year didn’t have the winds and currents necessary to maintain the network of marine food crucial to the seabirds’ diet. Breeding failures during the summer were preceded by tens of thousands of birds washing up dead on beaches in Washington, Oregon and California.
In Washington, the state’s largest colony of glaucous-winged gulls suffered when the normal fledge count plummeted from 8,000 chicks to 88 last year.
The breeding failure isn’t expected to harm the birds’ overall population, but it has raised questions.
“The whole process broke down,” said University of Washington researcher Julia Parrish, who witnessed bird deaths repeatedly last summer while observing 6,000 nesting murres on the island about a half mile off Cape Flattery at the tip of the peninsula. “We don’t know what happened.”
Researchers met over the issue earlier this month in Seattle, but were unable to trace the source of the strange weather, except to consider global warming’s effects in the past year.
The oceanographers, atmospheric scientists, marine mammal experts, seabird biologists and researchers who model ecosystems and ocean circulation now plan to write a series of scientific papers carefully documenting their observations.
Last year, the region enjoyed sunny winter days with little snow in the mountains. The warm, dry weather also marked the third year of above-normal ocean temperatures.
In early spring, the rain came. And when the birds should have been making and feeding babies, they were instead found dead.
“It was the birds that were the first harbingers of this whole problem,” said Bill Peterson of the National Oceanic and Atmospheric Administration, which set up the Seattle meeting.
At the same time, researchers recorded low catches of juvenile salmon and rockfish, and there were sightings of emaciated gray whales. Those findings were preceded by the first appearance in Washington waters of thousands of squid normally not found north of San Francisco. And a plankton typically found near San Diego bloomed along Northwest beaches.
Scientists say to expect more of the same as the planet warms and weather patterns are altered.
“There are all these unconnected reports of biological failures,” said John McGowan of the Scripps Institution of Oceanography in La Jolla, Calif. “It’s all the way up and down the coast. … There’s a lot of evidence there are important changes going on in the Pacific coast system.”
Parrish directs the Coastal Observation and Seabird Survey Team, made up of 300 volunteers who scour Oregon and Washington beaches for dead birds.
Based on monthly surveys, researchers estimate the dead birds numbered in the tens of thousands, mostly Brandt’s cormorants and common murres.
“They were clearly starving to death – no fat, reduced musculature,” Parrish said. “The smoking gun is no food.”
The cormorant and murre both rely heavily on diving deep underwater for small schooling baitfish that also feed whales, seals, salmon and other animals.
Murres on Tatoosh Island feed on sand lance, herring, surf smelt and eulachon.
Last summer the birds couldn’t find any sand lance and hardly any herring. Catches of the other two fish also were reduced.
Parrish’s team instead saw the birds preying on the Pacific saury, a rare sight in 14 years of observations.
“The steak and chicken fell out of the diet,” Parrish said. “It’s like going to the grocery store and (seeing) there are only a few yucky things in the store. You adapt by using what’s there.”
Throughout the West Coast researchers recorded similar findings.
At Triangle Island in British Columbia and California’s Farallon Islands, scientists saw a third seabird, the Cassin’s auklet, show signs of starvation, said Bill Sydeman of the Point Reyes Bird Observatory.
The Farallon auklets started the breeding season late. Only half as many as normal even tried. Then they abandoned the nests.
“That’s unprecedented in 35 years of studying Cassin’s auklets on the Farallons,” Sydeman said.
Along the Washington and Oregon coasts, researchers believe it was the lack of winds that led to birds’ deaths.
In the spring, the Aleutian Low, a weather system that brings winter storms to the area, begins moving north. Winds push the surface of the Pacific Ocean to the southwest, allowing deeper, colder ocean water to surge in, bringing with it nutrients from dead plankton, dead fish and fish excrement.
“Basically, you can think of it as a lot of schmutz that settles to the bottom,” Parrish said.
Without that perennial fertilization, there’s no plankton, therefore breaking the food cycle for many fish and birds.
Last year, winds from the north didn’t really materialize until mid-July, instead of the normal March or April.
In the last 30 years, the top 300 feet of the Pacific warmed and became more dense, said Scripps’ McGowan, whose institution has studied ocean temperatures since 1919 and started a comprehensive Pacific monitoring project in 1949.
Off Southern California, zooplankton are down 70 percent, fish larvae 50 percent, and there have been massive die-offs of kelp.
In Puget Sound, the number of seabirds has dropped by nearly half since the 1970s. Nearly a third of seabird species are legally protected or candidates for protection.
“All kinds of things are changing, and the biology is responding in funny, nonlinear, confusing ways,” McGowan said. “Not everything has declined, but many things have.”
Information from: Seattle Post-Intelligencer, http://www.seattle-pi.com/