Pipilo chlorurus

BREEDING: Thickets, chaparral, shrublands, riparian scrub, and especially sagebrush (Artemisia spp). Habitat varies with elevation. Primarily in mountains (AOU 1983, Dobbs et al. 1998). Found on mountain slopes, plateaus, and higher valleys of arid West, associated with dense shrubs 0.5 to 1.5 m in height; most commonly uses dry shrubby hillsides and post-disturbance shrubby second growth (Dobbs et al. 1998, Knopf et al. 1990). Occurs up to 2400 m in elevation in Great Basin; 3000 m in Arizona; between 2100 m and 3400 m in New Mexico (Bailey 1928, Ligon 1961, Rising 1996). Rarely found below 1200 m (Burleigh 1972). Apparently attracted to dwarf mistletoe as a nest, roost or foraging site in southwestern ponderosa pine (Pinus ponderosa) forests (Anonymous 1991). Nests on or near ground in shrubby habitat; nest is usually under cover of brush or plant tufts; built by the female. Habitat is usually low shrubs, sometimes interspersed with trees; avoids typical forest, other than open pinyon-juniper woodlands (Dobbs et al. 1998). In pinyon-juniper, associated with sagebrush (Artemisia spp.) dominated openings with high shrub species richness (Sedgwick 1987); uses juniper for song perches (Maser and Gashwiler 1978). In shrub-steppe habitats prefers ecotones between sagebrush and other shrubby habitats, especially mountain mahogany (Cercocarpus spp); often select a central bush of another shrub species within sagebrush-dominated patches; high shrub patch vigor (percent live branches and standing herbaceous biomass) important to nesting microhabitat (Knopf et al. 1990). In northern Great Basin, uses tall sagebrush/bunchgrass, squaw/sagebrush/bunchgrass, mountain mahogany/bunchgrass, mountain mahogany/pinegrass and aspen/sagebrush/bunchgrass communities as primary breeding and foraging habitat (Maser et al. 1984). In Montana, found in sagebrush habitats and higher elevation shrubby second-growth (Hutto 1995). In Colorado, recorded in Gambel oak (Quercus gambelli), aspen/willow and spruce/aspen habitats (Winternitz 1976, Dobbs et al. 1998). In Arizona, nests in dry, high-elevation sites dominated by shrubby New Mexico locust (Robina neomexicana) and small conifers under canopy of ponderosa pine (Martin 1993b, Dobbs et al. 1998); also in shrubby understories of open riparian corridors and saltbush (Atriplex) along field edges (Rosenberg et al. 1991). In Sierra Nevada, observed in high numbers in dense successional brushfield that developed 8 to 15 years after fire in a pine-fir forest (Bock et al. 1978). In Baja California, breeding birds observed in aspen and in meadow openings within mixed coniferous forest at 2700 m (Erickson and Wurster 1998).

NON-BREEDING: Primarily in lowland habitats (AOU 1983, Dobbs et al. 1998). In Mexico, found in dry desert habitat with acacia, mesquite, and creosote bush (R.L. Hutto reported in Dobbs et al. 1998). Possibly limited in habitat use by distribution of water. Unlike desert-adapted sparrows, towhees are not tolerant of saline water (Smith and Ohmart 1969, Dobbs et al. 1998).

In Colorado, mean breeding density reported at 3.0 pairs per 40 ha in aspen/willow and spruce/aspen stands (Winternitz 1976).

Mean predation rates for shrub nesting species in generalized shrub/grassland habitats 40% to 44% (Martin 1993a, Martin 1995). On Mogollon Rim, Arizona, observed > 75% nests failure due to nest predators (Martin and Li 1992, Dobbs et al. 1998). Reported predators include accipiters, peregrine falcon (Falco peregrinus), American kestrel (Falco sparverius), long-eared owl (Asio otus), red-tailed hawk (Buteo jamaicensis), Steller's jay (Cyanocitta stelleri), black-billed magpie (Pica pica), red squirrel (Tamiasciurus hudsonicus), least chipmunk (Eutamias minimus), long-tailed weasel (Mustela frenata), striped skunk (Mephitis mephitis), spotted skunk (Spilogale putorius), and gopher snake (Pituophis melanoleucus) (Dobbs et al. 1998).

Recorded as an occasional host of brown-headed cowbird (Molothrus ater) (Friedmann et al. 1977, Ehrlich et al. 1988, Dobbs et al. 1998). Mean cowbird parasitism rates for shrub-nesting species in generalized shrub/grassland habitats 15% (Martin 1993a, 1993b), but extent of parasitism unknown.

Clutch size two to four (usually four). Nestlings altricial and downy.