The Tsirku River is a braided river near Haines, Alaska that eventually flows into the Chilkat River. At that intersection of the two rivers, the Tsirku River spreads out into a huge alluvial fan river delta. That area, is the primary area where bald eagles gather on the Chilkat River in the Alaska Chilkat Bald Eagle Preserve. This downriver view of the Tsirku River is several miles before the river leaves the steep walls of the river valley and forms the alluvial fan river delta.<br /> <br /> Bald eagles come to the alluvial delta area at the confluence of the Tsirku and Chilkat Rivers because of the availability of spawned-out salmon and open waters in late fall and early winter. The open water is due to a deep accumulation of gravel and sand that acts as a large water reservoir whose water temperature remains 10 to 20 degrees warmer than the surrounding water temperature. This warmer water seeps into the Chilkat River, keeping a five mile stretch of the river from freezing.
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