Researcher Chloe Goodson’s tally of more than 1,400 eagles during a roadside count last week bodes well for next week’s Alaska Bald Eagle Festival.
Goodson counted over 700 birds along the Chilkat at the 19 Mile slide and 378 birds at 21 Mile. “If you go out and park on the edge of the slide, you’ll see a whole ton of birds,” she said.
Goodson is in her third year of leading counts of eagles that start migrating here from around the region in September. The congregation typically peaks in mid-November, with historic counts reaching over 3,000 birds.
Pam Randles, who conducted the counts for seven years, said she was encouraged by Goodson’s numbers. Last year’s congregation numbered over 2,000 birds.
“Something’s going on. Either salmon runs are increasing or cold is freezing the tributaries. I don’t know which it is, but I’m glad to see the numbers come back up,” Randles said. From 2009 to 2015 Randles’ counts averaged between 700 and 900 eagles.
Changes in how eagles are counted are significant for understanding numbers. Goodson’s counts are limited to birds that can be seen from the road system, including the Tsirku River fan near 20 Mile, where warm upwellings keep the Chilkat River free of ice, guaranteeing eagles access to salmon, even in sub-freezing weather. Other surveys, from slow-moving airplanes, allowed for a more comprehensive count. Those surveys resulted in counts that routinely topped 2,000 eagles.
Historically, colder weather meant fewer eagles. But with warm temperatures, river tributaries don’t freeze up and eagles can find salmon in many locations, including tributaries of the Kicking Horse and upper Tsirku River, away from the road system and from Goodson’s binoculars. “You wouldn’t be able to see them all from the road,” Randles explained.
Randles said there’s no way to compare results of road counts to aerial eagle surveys, as aerial surveys were done sporadically. Nonetheless, she’ll spend the winter compiling all the surveys done since 1988, including how and where they were done.
Researchers will be able to compare ground counts that followed identical methodology for the past 13 years. “Plus, I’ll have lots of graphs in there, too,” said Randles.
Goodson will share her findings during the festival at the American Eagle Foundation on Wednesdat at 7 p.m..
How salmon returns might be impacting the eagle migration was difficult to say this week. The eagle migration feeds predominantly on fall chum salmon and, to a lesser extent, coho salmon.
The coho escapement this fall was 35,000, compared to an escapement goal of 30,000 to 70,000 fish. “It was a well-below average run but it is within the escapement goal,” said Fish and Game sport fish biologist Rich Chapell.
Commercial fisheries assistant area biologist Wyatt Fournier said chum salmon escapement in the Chilkat River this year was about average.