Breeds patchily in south-western USA (from southern Nevada and southern Utah south to southern California, east to extreme western Texas) and extreme northern Mexico (northern Chihuahua). Migrates to coastal regions of western Mexico, mainly from southern Sonora south to western Guerrero.
 
Population
Estimated population is 1,200,000 (2010).
Lucy's Warbler (Leiothlypis luciae) [XC800848]
by Peter Ward from Fort Lowell Park (near Tucson), Pima County, Arizona, United States (begging call)
Lucy's Warbler (Leiothlypis luciae) [XC323620]
by Antonio Xeira from San Bernardino National Wildlife Refuge, Cochise County, Arizona, United States (call)