Species: Amphispiza bilineata

Relative abundances recorded on BBS routes are high, ranging from and average 11.76 to 23.42 birds per 25-mile survey route. Density of 7 per 40 hectares has been reported for desert scrub creosote-burrobush habitat in California (Kubik and Remsen 1977); in another study, 3.9 per 40 hectares (Bureau of Land Management, no date). In southern Utah, breeding densities ranged from 4.3 to 9.6 pairs per 40 hectares (Medin 1986). In a creosote bush community in Nevada, occurred in densities of 43-61 pairs per 100 hectares (Hill 1980). In Baja California, average density of individuals was significantly higher on island study sites (16 individuals per 10 hectares) than on mainland sites (7.0 per 10 hectares; George 1987a). In New Mexico creosote bush scrub habitat, territory sizes were estimated at 120-150 meters in diameter (Heckenlively 1967). <br><br>Chases are common among males when territories are being established (Rising 1996). Visibility in habitat can be limited, and singing both elicits defense behavior and is apparently the most frequent response for territorial defense (Heckenlively 1967). <br><br>During nonbreeding season, found in small foraging flocks and often in mixed-species flocks that may include sage sparrows (AMPHISPIZA BELLI), Brewer's sparrows (SPIZELLA BREWERI), white-crowned sparrows (ZONOTRICHIA LEUCOPHRYS), vesper sparrows (POOECETES GRAMINEUS), cactus wrens (CAMPYLORHYNCHUS BRUNNEICAPILLUS) or verdins (AURIPARUS FLAVICEPS; Ehrlich et al. 1988, Rising 1996). <br><br>In a study conducted between early March and late May in southern Arizona, birds foraged on ground more than 90 percent of the time (Parker 1986). Seed foraging is apparently facilitated by the presence of rodents and ants, possibly through the creation of runways and bare areas which the sparrows use for visual foraging. Sparrow abundance declined over the long-term with the removal of rodents and ants (Thompson et al. 1991).