The Usotanai River is known as a river of gold sand, and in the fall, salmon (also known as chum salmon and akizasa mackerel) and pink salmon return to the river to spawn.
The abundant spring water from the 761-meter-high Mt. Zhumun is essential for salmon and trout to spawn and grow their eggs, and many fish return to their home rivers.
The "hotchare" of salmon and trout that have finished spawning and died of exhaustion are used by brown bears, foxes, crows, gulls, and other predators as important nourishment that brings abundant blessings to the forest.
Especially in November, Steller's sea eagles and white-tailed sea eagles, which have spent the summer in Sakhalin, Russia, and other regions, migrate to the area and gather here for the hotchpotch preserved in refrigeration in the rivers.

The peak season for eagles is mid-December, when the number of eagles reaches 400-500 in most years. The "eagle tree," where many eagles rest and 50-60 eagles per tree, is one of the attractions of the area.
After January, the number of eagles decreases and they are expected to migrate to the east of Hokkaido.

The area is carefully watched over as a "Steller's sea eagle forest. We ask visitors to observe them with good manners.
Some visitors enter the meadows and riparian forests to take photographs, and some visitors try to approach the eagles on foot. We ask for your cooperation in creating an environment where eagles can rest in peace.
We have also seen some dangerous situations such as long hours of on-street parking on roads, and people setting up tripods on bridges to take photos. With snow and icy roads, even a single car is obstructing traffic.
When observing, please park your car in the parking lot of the Uzodan Livelihood Improvement Center and observe and photograph with the safety of your surroundings and yourself as a priority.