Watching and Waiting:
Sea Grant-funded Study Tracks Changes in Western Washington's Marine Birds
Thirty years ago, Terry Wahl was able to count as many as 15,000 western grebes from a window of his Bellingham Bay home. Today, he says it is rare for him to see more than 2,000 of the marine bird species in the bay.
"You just can't find them like you used to," says Wahl, who has lived in that same house for 49 years. "There is still a flock, and a flock will impress people, but I used to see six to eight flocks in that same area. Sadly, I've seen similar population decreases in other marine bird species as well."
As a co-principle investigator of the 1978-79 Marine Ecosystems Analysis (MESA) Puget Sound Project, Wahl is no amateur birdwatcher. Funded by the National Oceanic and Atmospheric Association and the U.S. Environmental Protection Agency, MESA was an attempt to assess the populations of fish, seals and sea lions and other marine species in northwestern Washington, and it was Wahl who was in charge of the marine bird census.
Unfortunately, Wahl is not the only one who has noticed a population decline in many marine bird species since the MESA study was conducted 25 years ago. Using MESA findings as a baseline, several other studies have also shown substantial population declines in recent years. However, in their comparisons, none of those studies replicated more than one aspect of the multifaceted MESA study.
A Follow-up to MESA
That is about to change. With funding from the Washington Sea Grant and other sources, John Bower, an associate professor at Western Washington University's Fairhaven College, has finished the first year of a two-year study that closely replicates the MESA study.
"After meeting with Terry and discussing the changes he's witnessed in the last 25 years, it seemed to me that there was a real need to do a very comprehensive comparison to the MESA study," says Bower. "The study will also allow us to see how accurate these others studies are, because some of their findings show population declines as high as 95 percent in certain species."
Replicating the MESA study has been no small task. To date, Bower has involved 38 Western Washington University (WWU) undergraduates and three graduate students in his census work.
"Fairhaven encourages very intensive student/teacher interactions," says Bower, "and as a science professor here, it is very important for me to have a research program that invites undergraduate and graduate students to be a part of it."
Students as Study Assistants
Before students are sent into the field to count marine birds, they must first learn how to identify about 90 marine bird species. However, Bower says the study is chiefly concerned with the 30 or so species that commonly winter or breed in northwestern Washington.
Once students are trained in identification, they are sent to many of the same sites that MESA volunteers were sent to in the late 1970s. "We usually have five teams a week go out and count birds for between five and 10 hours each time," says Bower. "We go to about 150 spots along the coast, and we do counts from three ferries." Students also perform marine bird censuses from aboard the Bellingham-based Island Mariner whalewatch boat.
"It's been a challenging experience," says Holly Donovan, a senior in environmental studies at WWU. "It really is tough to go out and spend six hours in the rain and wind, staring down the Strait of Georgia counting birds and identifying them, but it's been so rewarding. I've really grown to appreciate marine bird ecology."
Before Bower started his research in February 2003, the most comprehensive marine bird population work since MESA had been conducted by the Puget Sound Ambient Monitoring Program (PSAMP). Funded by the State of Washington since 1992, PSAMP researchers have conducted population surveys from an airplane twice a year and compared their results with MESA data to calculate population declines or increases.
While Bower notes that the PSAMP work is important, he says it is limited by the fact that aerial population surveys were only a minor part of the MESA project. By design, Bower's study more closely resembles the MESA project, which was more reliant on shore-based population counts, as well as counts from aboard Washington state and British Columbia ferries.
Nevertheless, Bower says the preliminary results from the first year of his study agree with many of the findings of other studies, including PSAMP.
Ups and Downs
As Wahl had noticed from the window of his Bellingham Bay home, one of the most dramatic population declines in the last 25 years has occurred in the western grebe. While PSAMP data has shown the decline as high as 95 percent, Bower's preliminary data has the decline at 77 percent.
"The western grebe is a beautiful bird," says Bower. "In the '70s, MESA volunteers would report seeing thousands of them on the water. Today, we never see that. We just never see it."
While Bower's results for many marine bird species agree with much of the PSAMP data, there are also some significant differences. An example is the population of pigeon guillemot, which PSAMP's data showed is down 55 percent. However, Bower's data have shown a 60 percent increase in pigeon guillemot since the late 1970s.
"There are some areas where we disagree," says Bower, "and one of the tricky things is going to be figuring out what exactly that means. We're not quite there yet, but we'll know more when the second year of counts is complete."
Although some marine bird populations appear to be growing, the reality is that a majority of species are headed downward, according to Bower. "If you put together all the species we're counting, there is a 53-percent overall decline in the number of birds on the water," he says. "At least two-thirds of the species we're studying are showing population declines."
Causes and Effects
Bower says the marine bird population declines could be attributed to a variety of factors, many of which will differ from species to species.
"Changes in forage fish populations probably have had an impact on marine bird populations," he says. "Humans are affecting fish species in many different ways: through fishing, through pollutants, through altering spawning habitat and, possibly, through climate change."
There are other factors that scientists still don't know enough about, he says. One example is the effect of pollution levels on the thinning of eggshells. "It's just not known what effect the pollutants we're putting in the water have on marine birds. It's pretty complex and the story for each species is probably different."
It will be up to other researchers to find out what is causing these population declines, says Bower. "For me, this study is a starting place," he says. "Our work is going to point towards those species that need follow- up study to better understand why their populations are declining."
Bower is quick to point out the importance of birds to humans. In addition to possibly losing a beautiful part of nature, birds have been shown to be excellent environmental indicators, he explains.
"One selfish way to think about this is that those environmental changes are likely to affect us," says Bower. "So the birds are like the canary in the coal mine, telling us that we need to focus on the marine environment."
Summer 2004
Contact David G. Gordon, Science Writer for Washington Sea Grant, for further information.