Golden Spring: Golden Eagles Dominate the Sky Above the Copper River Basin
Arthur Green and Matt Dickey search the sky for raptors. Photo by Charlie Ebbers.
Charlie Ebbers - CRR Staff
On any clear spring day, the sky above the Copper River Basin is full of raptors. They’re pouring back into Alaska from the Outside, having just passed through the Wrangells. They’re headed home.
Golden eagles are the dominant species of raptors in this region, according to a dedicated conservation group, scientists, and local observers. Every year, eagles go from and come back to Alaska because, like salmon, this is where they originated from. Unlike salmon, the eagles are back to eat meat, lay eggs, and rear the next generation.
The first eagles that leave their wintering grounds are the mature birds, which seek to return to their “nesting territories,” says Carol McIntyre, a wildlife biologist with Denali National Park and Preserve. The birds returning to their Alaskan aerie need to get back as soon as possible.
Eagle eggs need to incubate for at least 40 days, and then it takes another 60- 70 days for the nestlings to be able to fly on their own power. A short window of time to gain enough size and ability to be prepared for the flight south come the fall equinox.
“It’s a one-way street right now,” says Arthur Green, his spotting scope pointed towards a ridge about three miles north. “There’s a sharp-skinned Hawk on that ridgeline,” he said. Green’s fellow volunteer added another hash mark to his notes. The hawk goes into its category on the data set, soon to be added to the overall count.
The number of recorded golden eagles soaring past HawkWatch International’s observation station has hit all-time highs in 2021 and 2022. The 2022 study closed on Sunday, May 15, and Green and his colleague Matt Dickey recorded 1847 Golden Eagles this year with about 542 observation hours since March 10. It’s unknown how many eagles live in Alaska, but the US Fish and Wildlife Service estimates 39,000-40,000 golden eagles in the entire United States.
While the sharp-skinned was too far to catch its plumage, indicating gender and age, its presence and the rest of the raptors passing through are noted. The HawkWatch group keeps a long-term view on raptor numbers funneling through that area. In 2021, there were 1,707 Golden Eagles seen with nearly 529 field hours. In 2018, there were 1,020 Golden Eagles spotted in about 516 hours of observation.
Green and Dickey have been bundled up, watching, nearly every day for two months, enduring the elements of late winter and early spring at a highway pull-out just west of Eureka.
The Golden Eagle project started in 2003 in collaboration with the Alaska Department of Fish and Game. Since that time, HawkWatch has only missed a couple of years of record keeping. However, a spring count tends to give a more accurate number of a population due to many fledglings perishing throughout their winter travels.
Once they’re back in Alaska, Gunsight Mountain is believed to be somewhat of an aerial bottleneck for migration through the Copper Basin.
If eagles take the valley north of Gunsight, it’s assumed they’re headed to the Talkeetna Mountains. They’re headed for the Mat-Su, Kenai, Alaska Peninsula, and Aleutians if they take the southern valley.
Some cruise around the state all summer. Green’s observation setup at the highway pull-out is in an ideal location to record migration numbers.
With his spotting scope, Green likely to see whatever passes through on a clear day. As he says, his site was chosen because it’s “utterly pragmatic, it is accessible in almost any weather conditions.”
Generally speaking, nesters are soaring to their established territories, while juveniles try to make themselves scarce and head towards the hinterlands. Many young birds end up on the North Slope to find prey.
Green explained how all raptors strive to soar on good thermals up the Rockies, choosing to cruise over forests that trap heat while open snowy stretches are energy sinks for the birds during their migration.
There is no exact location, or even region, where eagles winter. But eagles tagged in Denali have been found as far south as central Mexico. If an eagle makes it through its first year, there’s a good chance it’ll live to be 15-25 years old. The oldest known Golden Eagle was 31, according to the Cornell Lab of Ornithology.
People often ask Green, “How do you know you’re not counting the same bird twice?” From his experience, he says it’s easy to distinguish between the birds passing through. Every bird’s plumage is different, and they’re traveling, not dallying, on their way home.