Their last feast of the season is due to a fortuitous quirk of nature. The steep mountains along the Chilkat Valley, which is just a hop from Glacier Bay National Park, have many small glaciers, and over the years the glaciers have reduced rocks to sand and gravel. That debris has washed down the hillsides and formed what is known as an "alluvial fan reservoir." Alluvial fans can be seen at the foot of most mountain valleys, where debris collects and forms what really looks like a giant fan.
But what makes this fan different is the amount of water that collects between the chunks of gravel several feet below the surface.
"Water percolates through the gravel," says Telford, "and that keeps it warmer than surface temperatures."
The water from the underground reservoir rejoins the Chilkat River near the village of Klukwan, and it is 10 to 20 degrees warmer than the water in the river. That keeps the river from freezing, and much of the river stays open for several miles south of the village.
Meanwhile, chum salmon, which are generally regarded as the least palatable to humans, make their way up the Chilkat to spawn. The best place to do that is in the last stretch of water below the village. Elsewhere in southeast Alaska, the last runs of salmon ended months ago.
So each November, thousands of visitors show up to watch thousands of eagles gorge on the last run of the year.
It's a unique opportunity for people who care a lot about the national symbol to try to repair some of damage done by humans. Eagles often fall victim to power lines, and even automobiles, as they go about their difficult task of staying alive.
So two or three eagles rehabilitated by volunteer centers are released back into the wild during each festival. At least for the time being, they will have plenty to eat.
And then the last of the salmon will be gone. The eagles will have to struggle through the cold months of winter, when food will be very scarce. Some of them won't make it.
But most of them will. And they'll be back here again next year, along the banks of the Chilkat River.