These sparrows seem to be migrants in Oasis Valley in spring and fall (the fall movement being lengthy, from July to October). They hang out in moist habitats and edges, such as cattail marshes, cottonwood thickets, streamsides, weed patches in old fields, and gardens.
This guy lost his tail, but seemed to do well living in my garden one fall -- I saw him every day for weeks.
^Lincoln's sparrow in a Russian olive (an introduced tree) by a sedge-bulrush marsh.
In the Southwest, they winter along the lower Colorado River and southern Arizona, and some in southern Nevada. Sporodic winter records occur at Furnace Creek Ranch in Death Valley, about 40 miles to the southwest of Oasis Valley.
Breeding occurs in moist meadows of boreal mountain ranges of the western Sierra Nevada, Oregon, and Idaho. The Jarbridge Range in far northeastern Nevada has nesting records, but most of the Great Basin is apparently too arid for these sparrows to breed in (Atlas of Breeding Birds of Nevada, Floyd et al. 2007).