STEVE INSKEEP, Host:
Researchers in the Pacific Northwest are trying to figure out why seabirds seem to be disappearing. These are birds that normally would travel from California to Canada. Some birds are starving to death, some are not reproducing, and some have simply vanished. Deidre Kennedy reports from Seattle.
DEIDRE KENNEDY: About 30 minutes West of Seattle, off Bainbridge Island, Washington State wildlife biologist Joe Evanson(ph) spends his days on a small boat. He is tracking black and white sea ducks called surf scoters.
JOE EVANSON: So he is towards our bow and to the starboard a few degrees probably.
KENNEDY: That beeping sound is coming from a transmitter inside a duck's stomach. It's sending out signals from a small silver VHS antenna poking up from the duck's back. From a distance, the bird looks a little like a remote controlled toy bobbing up and down on the water.
EVANSON: Each of the birds has a different frequency, radio frequency that is transmitting. That way we can tell which bird is which.
KENNEDY: Evanson reports the location of each duck on a map that will tell researchers from California to Canada where the birds are feeding, where they go to rest, and whether or not they return to the breeding grounds.
These birds spend the winter here, in the Puget Sound, gorging on mussels, herring and other small fish to fatten up before they fly off to their nesting grounds in the Arctic. Back in the 1970s, you could see tens of thousands of scoters feeding in these waters. Now they gather in the hundreds.
Joe Gaydos is a veterinarian assisting in the sea duck study. He says scoters aren't even the worst-hit population. Western Grebes, best known for their distinctive Mohawk hairstyle, are also affected.
JOSEPH GAYDOS: Western Grebes, approximately 25 percent of the world's population will winter here in the Puget Sound area. Well, they've declined 90 percent over the last decade. That's pretty dramatic.
KENNEDY: Declines and die-offs have also spread beyond the Puget Sound. Last summer, Glaucus-winged Gulls, who normally hatch about 10,000 chicks in Washington, hatched fewer than 100. And thousands of emaciated Common Murres and Brandt's Cormorants dropped out of the sky or washed up along the Pacific Northwest Coast.
University of Washington researcher Julia Parrish says there was a malfunction in the ocean's annual upwelling process last spring. That's when cold water wells up from the deep, delivering a rich soup of nutrients.
JULIA PARRISH: And then all of the birds and the marine mammals and the salmon and the rockfish and the ling cod all come in and everybody chows down and has a good time.
Last spring, upwelling was wimpy. There wasn't a lot of plankton around. The bottom fell out of the ecosystem.
KENNEDY: But the wimpy upwelling theory doesn't solve the mystery. The most significant hole in the theory? It doesn't explain the declining seabird numbers before last year.
Veterinarian Joe Gaydos.
GAYDOS: Myself and many other scientists in the area are alarmed that it's not just a cyclical change that we're going to swing back up. We really think that there is something going on underneath the surface of the water that we need to figure out.
KENNEDY: Scientists say they're scratching their heads as to what that is. There are a few popular ideas out there. Pollution is one. Another idea is that global warming may be creating unforeseen consequences in the ocean's cyclical patterns.
For now, scientists won't commit to one theory. What they will say, though, is that this summer's bird count will be a crucial indicator of the future of the Northwest bird population.
For NPR News, I'm Deirdre Kennedy.
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