It was hard to miss the flocks of thousands of black-bodied and white-faced birds bouncing in the waves near the shoreline along Lutak Road in April.
As they drifted along, dozens of birds at a time dove from the front of the flock, reappearing after a half minute or so at the back in a perpetual conveyor belt.
The birds are surf scoters and they are looking for different courses of the feast the Lynn Canal offers up in spring — blue mussels latched onto rocks on the ocean floor, and herring and eulachon eggs.
The abundant food attracts close to 30,000 scoters to the Chilkat Valley each spring, which is up to 20% of the global population of the species according to a recently-published analysis.
Surf scoters are just one of 18 species of which at least 1% of their worldwide population passes through the Alaska Chilkat Bald Eagle Preserve. The Audubon Society says that makes the preserve an area of “global significance.”
Nature lovers said the findings speak to the wealth of the Chilkat Valley’s ecosystem.
“The numbers are super validating and really exciting,” said Stacie Evans, a biologist for Takshanuk Watershed Council who was not involved with the research. “We call (the Chilkat Valley) the land of superlatives. Every year I study here, it seems like we rack up another one.”
The numbers for the Audubon report were compiled using data gathered by citizens using the popular E-Bird app from the Cornell Ornithology Lab. Hundreds of thousands of users around the world log bird species that are then automatically tagged for locations.
Researchers can access that data by region to come up with local abundance estimates. Bill DeLuca, a migratory bird researcher for the Audubon Society, came up with a model used for the Chilkat study as well as a handful of others.
He said the 48,000-acre Chilkat Bald Eagle Preserve stands out for being among the smallest areas where he’s done the study.
“When I first did this because it was so small, I had low expectations to be honest with you,” said DeLuca, who is also a professor in the College of Natural Sciences at the University of Massachusetts-Amherst, said he has visited the preserve multiple times. “I was worried the numbers weren’t going to reflect what is there.”
Turns out he didn’t have to worry.
The estimate that 18% of the world population of surf scoters pass through stood out among species, but the report found the Haines area sees globally significant populations of other species too.
Glaucous-winged gulls, Barrow’s goldeneyes, Western sandpipers, and Bonaparte’s gulls were all estimated at 2% of the total worldwide species count passing through in the spring. Bald eagles, and sharp-shinned hawks all had at least 2% of their population pass through in the fall. Evans said that finding the land-based birds like sharp-shinned hawks, which feed mostly on smaller birds and rodents, in high abundance was significant.
“We know we have a lot of biodiversity. This study shows that we also have a lot of abundance here as well. Biomass is really important for keeping the life pulse going,” Evans said.
Nicholas Szatkowski, a naturalist who lives near the Little Salmon River about 30 miles north of Haines, said the reasons for the prolific bird migration make sense. The Chilkat Pass, which tops out at around 3,400 feet above sea level, gives birds and other species a relatively easy way to access the Interior.
“The valley plays a critical role in facilitating that migration from the coast to the interior,” Szatkowski said.
The study was originally published in mid-2023, but was widely shared after the Audubon Society published an explainer story earlier in May. It relied on just one year of data collection, which DeLuca acknowledged could skew results based on year-to-year environmental conditions. Still, having such high numbers of certain species and having a high prevalence of so many species stood out to Evans.
“There’s always gonna be a certain amount of error in a study like that but when you’re getting such dramatic results, it’s clear something is going on there,” she said.
Szatkowski said there’s another factor that might contribute to an undercount of species — the lack of roads in the Chilkat Valley compared to other parts of the country. He said because many productive waterfowl habitats and forests don’t have roads through them, fewer people visit.
“It doesn’t make the data wrong, but it’s just another limitation,” said Szatkowski.
Local nature watchers hope the study is the first of many that can validate what they already know about the area. And they hope it will inspire the community to protect areas that nourish species passing through the valley, even if the birds don’t stay through the whole year.