Le Conte's Thrasher is paler and lacks rusty undertail coverts. California Thrasher has a paler supercilium and darker cheeks. The ranges of California and Crissal Thrashers do not overlap much. Other thrashers have spotted underparts and pale eyes.
Length and wingspan from: Robbins, C.S., Bruun, B., Zim, H.S., (1966). Birds of North America. New York: Western Publishing Company, Inc.