Last fall, Stacie Evans counted fewer bald eagles around Haines than in any survey since 1986, when counts began.
On the peak day in 2020, Evans observed only 279 eagles, down from 1,238 the year before. Two decades ago, peak counts eclipsed 2,000 birds.
Evans, who is Takshanuk Watershed Council’s science director, said the survey data alone aren’t sufficient to prove causation or to draw conclusions about Haines’ bald eagle population. Nonetheless, over time the counts can provide insight into general population trends.
Although several years have gone without counts, Takshanuk Watershed Council’s data appears to show a general downward trend in ground surveys of eagles from 1986 through 2020.
The especially low count in 2020 coincided with a poor chum salmon run: last year was the first time since 1999 that Chilkat River chum failed to meet the state’s escapement goal of 75,000 to 250,000 fish.
Every fall hundreds of eagles come to Haines to take advantage of the late chum run up the Chilkat, a rare winter food source. An upwelling of groundwater where the Tsirku and Klehini rivers feed into the Chilkat keeps the latter from freezing. The warm water provides a spawning ground for chum—a primary food source for bald eagles.
“Last year, without chum salmon, my hunch is that we were just seeing our resident eagles, and the eagles that usually come here during that time were finding food elsewhere,” Evans said. Still, she acknowledged, “I can’t say that the survey told me exactly that this is what’s going on with the eagles.”
This year’s chum run seems to be stronger than last year’s. The state estimates escapement in the Chilkat drainage to be 170,258 fish, within the target range, according to Alaska Department of Fish and Game biologist Nicole Zeiser. (The state’s Chilkat River fish wheels captured 2,639 fish, which the state estimates to be 1.53% of the total run.)
The fish draw birds, and the birds draw humans. The Alaska Bald Eagle Foundation hosts a festival in November, at peak eagle density, that attracts birders and photographers from far away places. The American Bald Eagle Foundation canceled the festival in 2020 and again this year due to COVID-19 concerns. Sidney Campbell, the foundation’s raptor program manager, said the foundation is imagining ways to adapt the festival if the eagle counts stay low.
“We are definitely concerned about what declining eagle numbers could mean for the tourism that helps make the festival happen,” Campbell said, adding that “it’s becoming less and less realistic for us to predict” Haines’ eagle numbers.
Evans tallies birds once a week from September through December at 12 sites, including Chilkoot Lake, Mud Bay and from 4 to 30 Mile along the Haines Highway. The U.S. Fish and Wildlife Service formerly conducted surveys at the Alaska Chilkat Bald Eagle Preserve, both from the ground like Takshanuk Watershed Council and from the air. But the agency stopped its surveys in 2000 for budgetary and administrative reasons.
Takshanuk Watershed Council took over the ground surveys in 2009, leaving a nine-year gap in data. Evans said their surveys aren’t population estimates and that aerial surveys would be needed to understand the area’s eagle population. Takshanuk Watershed Council is looking into using a drone to do its own aerial counts, possibly starting in 2022.
“If you really wanted to get an actual count of those eagles, you would need to get up in the air,” U.S. Fish and Wildlife Service wildlife biologist Steve Lewis said.
Both Lewis and Evans said the ground counts could be missing eagles that aren’t near the road: it’s possible that birds last year were more scattered across the preserve, or that the population has shifted to areas that can’t be seen from the ground survey sites.
Lewis said declines in the salmon population could have a “serious effect” on eagles, who flock to the Chilkat primarily for the chum. Other factors like weather and food availability elsewhere could have an effect, too. Without more data, it’s hard to know exactly what’s happening with the eagles, he said.
Although the Fish and Wildlife Service stopped doing local surveys in Haines, it continues to monitor bald eagles regionally. “We don’t have any indication that eagles in Alaska or eagles in Southeast Alaska are in decline at all,” Lewis said.