Takshanuk Watershed Council Science Director Stacie Evans said she started counting bald eagles in mid-September and will continue through mid-December.
She starts out along the Chilkoot River and counts at a few sites, then does one where Mud Bay Road and Small Tracts Road intersect. She then stops along the highway up to 30 Mile, which means she’s capturing a portion of the Klehini River as well.
The once-a-week count is not really a population estimate but it’s more of a snapshot of where the eagles are congregating along the Chilkat and Chilkoot rivers at any given point.
She uses a scope and essentially stands in one place and does a full 360-degree turn, counting each eagle she sees. She also does driving counts between 10 Mile Haines Highway and 18 Mile.
“I just drive really slow with my flashers on,” Evans said.
Evans didn’t design the eagle survey; she said that happened in the late 1980s. She’s not sure she’d keep those driving counts if she were to design a new survey today, but said it’s important to keep the data consistent and comparable to past years.
The last two weeks’ counts – that’s Oct. 31 and Nov. 4 – each yielded 308 individuals mostly concentrated around the 19 Mile slide area.
Evans said that’s less than half of what she counted last year when a Nov. 7 survey yielded 666 birds.
Evans wrote in an email that she suspects the lower number of birds is due to an “abysmal chum return” in 2020, which is the parent year for chum returning this year. Although the roadside count is low, Evans said that doesn’t necessarily mean the number of eagles is down.
It could mean they are congregating elsewhere, which is both weather dependent and influenced by where the salmon are running. So the concentration of eagles shifts around.
Evans said a cold snap could be helpful for people who are coming to view the eagles because a freeze-up on the Chilkat River would concentrate eagles at the council grounds where groundwater from an alluvial fan keeps the river open. Then it becomes a hot spot for eagles who are targeting the late run of chum salmon.
One thing the snapshot count is good for is tracking how well the bald eagle preserve is doing at providing habitat for eagles. Counting the eagles also helps scientists keep an eye on the health of the ecosystem. For example, in 2020, when there were low eagle numbers – Evans said it was clear something was off with the chum run, which also turned out to be low.
“Eagles are a very good indicator species. They’re easy to count and cheap to monitor,” she said.