Text and photos from National Audubon Society IBA Database Site Profile
Topaz Lake Site Description
One of a handful of IBAs shared with Nevada, this valley in the eastern Sierra Nevada at the northern tip of Mono Co. is formed by the west fork of the Walker River, which flows north into Nevada to feed Walker Lake in Nevada, one of the most important sites in the Great Basin for waterbirds. The California side of the valley begins at the town of Walker along Hwy. 395 and extends north to Topaz Lake, a medium-sized reservoir on the Nevada border. The southern side of the lake features a draw-down area where ducks, geese and shorebirds congregate during fall migration. The valley is extensively planted with alfalfa, but remnant stands of riparian woodland (highly restorable) persists along channels of the Walker River, all of which is located on private ranchlands. Updated by Eastern Sierra Audubon, October 2008.
This IBA has been extensively altered. Originally, the Walker River would have flowed through the Antelope Valley, cutting channels, forming oxbows and supporting patches of natural wetlands. This historic landscape is nearly gone, with the river now largely relegated to a central channel (thankfully, unlined), surrounded by and tapped for alfalfa cultivation, and dammed to form Topaz Lake. While this scene is not particularly threatened, this is an area that could benefit greatly from riparian and wetland restoration.
The West Walker River is one of a handful of major rivers connecting the Sierra Nevada of California with the vast wetlands of Nevada. Though research is still in its infancy, it is likely that these corridors, including the Walker, Carson and Truckee rivers, are major avian movement corridors between the Great Basin and California. Topaz Lake is the only regular breeding site for Bald Eagle south of Lake Tahoe, supporting just one pair each year (with several more in winter, ES). Swainson’s Hawk nests in the tall cottonwoods south of Topaz Lake, and Long-billed Curlew, another classic Great Basin breeder, nests in small numbers in the Antelope Valley, its only nesting site in Mono County. Finally, Bank Swallow maintains a small colony in a borrow pit (gravel mine) near the town of Topaz, and no doubt once bred commonly along the Walker River prior to its alteration. Occasional records of Yellow-billed Cuckoo from the Walker River (in Nevada) also suggest that this species may still be prospecting for breeding here. Today, large numbers of waterfowl visit Topaz Lake, particularly Common Loon migrating in early spring (fide Ted Beedy).
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