Comments: BREEDING: Frequents the arid, hot deserts of the West. Not closely associated with particular plant species or communities, but favors sparsely vegetated desert scrub, including thorn brush, cacti, chaparral, mesquite and juniper. It is most often found on desert uplands, alluvial fans, and hillsides where thorny xeric brush dominates, and sometimes also in dry shrubby washes, but avoids desert valley floors. Occurs from below sea level (Death Valley) to over 2,200 meters, but below 1,500 in northern parts of range (Bent 1968, AOU 1983, Howell and Webb 1995, Rising 1996). It uses all seral stages in desert habitats as long as vegetative cover is below 25 percent, and uses shrubs and cacti for foraging, song perches, lookouts, shelter and nesting (USDA Forest Service 1994). May take advantage of mammal burrows to escape desert heat (Austin and Smith 1974).
Found in a variety of desert scrub and chaparral habitats, including ocotillo (FOUQUIERIA SPLENDENS), cholla (OPUNTIA spp.), mesquite (PROSOPIS spp.), catclaw (ACACIA GREGGII), blackbrush (COLEOGYNE RAMOSISSIMA), saltbush (ATRIPLEX spp.), greasewood (SARCOBATUS VERMICULATUS), canotia (CANOTIA HOLACANTHA), and creosote bush (LARREA TRIDENTATA) interspersed with taller plants such as Joshua trees (YUCCA BREVIFOLIA). In other areas found in sagebrush (ARTEMISIA sp.), antelope brush (PURSHIA TRIDENTATA), or rabbitbrush (CHRYSOTHAMNUS spp.) interspersed with pinyon-juniper (Bent 1968, USDA Forest Service 1994, Rising 1996). In Idaho, recorded in open shrublands where dominant shrubs were more than 50 cm tall, in big sage (ARTEMISIA TRIDENTATA), spiny hopsage (ATRIPLEX SPINOSA), and horsebrush (TETRADYMIA spp.) along with other shrubs (Marks et al. 1980). On Tiburon Island, Baja California, found breeding in littoral scrub that included salt scrub and mangroves, as well as in xeric thorn scrub (Wauer 1992).
Nests are well-concealed and placed at the base of a bush or cactus, on or near the ground (but usually about 15-45 centimeters above ground) hidden in a grass tuft, fork of dense shrub, or joints of a cactus (USDA Forest Service 1994, Baicich and Harrison 1997). In Idaho, a sample of nine nests were all found 25-45 cm above the ground in big sagebrush shrubs, but sparrows were never observed in the dense stands of big sagebrush typically inhabited by sage sparrows (AMPHISPIZA BELLI) and Brewer's sparrows (SPIZELLA BREWERI). In Arizona, nests observed in bases of creosote bush and in cholla (Tomoff 1974). In south-central New Mexico, used 25 different plant species for nesting; placed nests within 49 cm of ground; nested significantly more frequently on uplands with abundant small shrubs than in arroyos, and produced larger clutches and fledged more young in upland territories (Kozma and Mathews 1997). In other studies, have been found nesting in shrubby washes and arroyos (Raitt and Maze 1968, Medin 1986). Preference for upland or wash may be tied to local availability of dense or spiny shrubs that afford concealment and protection, or perhaps avoidance of areas prone to flash floods.
NONBREEDING: In addition to xeric shrub habitats, may be found in riparian areas, grasslands and weedy fields away from desert region (AOU 1983, Rising 1996). Associated with shrubs in the grasslands of the Mexican Plateau, Chihuahua, Mexico (Colorado Bird Observatory 1997). Foraging flocks may follow local topography, particularly washes (Eichinger and Moriarty 1985).
FORAGING: Will forage in mesquite, catclaw, desert willow (SALIX sp.) for insects (Bent 1968).