Distribution: The Abert's towhee, Pipilo aberti, breeds in southwestern North America, in extreme southwestern Utah south along the Virgin and Colorado Rivers to Nevada, along the lower Colorado River of California and Mexico, and in the Gila River drainage of southern Utah and southwestern New Mexico (A.O.U. 1998). In Utah, Abert's towhee occurs along the Virgin River drainage south of LaVerkin, and the Santa Clara River drainage south of Gunlock (Tweit and Finch 1994).
Ecology: Abert's towhee is a permanent resident throughout its range. Its primary foods are insects, particularly beetles, ants, grasshoppers, and cicadas, and Chenopod seeds (Rosenberg et al.1991). Abert's towhee is primarily a ground forager and spends 50-60% of its time scratching on ground or loose litter (Marshall 1960). Territories are occupied year-round by permanent pairs. Nest building may begin as early as the first week of February in southern Utah, but the peak of nesting is early April through July (Finch 1984). Preferred nest sites are small trees and large shrubs. Nest height averages 155 cm early in the nesting season and 224 cm late in the season (Tweit and Finch 1994). Nesting territory size is 1.5 to 2 ha (Rosenberg et al. 1991).
Winter territories are much larger and birds tolerate adjacent pairs and floaters. Densities in well-developed cottonwood-willow habitat range from 55-107 birds/ 40 ha (Rosenberg et al. 1991), whereas densities in salt cedar-mesquite habitat are 30-49 birds/ 40 ha (Rosenberg 1987). Brown-headed cowbird parasitism of Abert's towhee nests has increased in recent years, due to a shortage of suitable of suitable sized hosts and an abundance of towhee nests (Finch 1983). Abert's towhee nests are parasitized more frequently in mesquite than in riparian habitat (Conine 1982), and parasitism is highest during May (45%) and June (67%) (Finch 1983). Cowbird survival in parasitized Abert's towhee nests is extremely low. Most young cowbirds cannot compete for food with the much larger towhee nestlings and starve (Finch 1983).
Habitat Requirements: Abert's towhee was formerly a year-round resident of the brushy under-story of cottonwood-willow riparian habitat and mesquite bosques along stream sides below 1,220 m (4,000 ft) elevation (Rosenberg et al. 1991). Most of this habitat has been modified or eliminated, and Abert's towhees are now found in cottonwood-willow remnants, exotic vegetation such as salt cedar, and mixed exotic/native habitat. In Utah, Abert's towhees are found primarily in salt cedar/willow riparian habitats. Abert's towhee populations disperse after the breeding season into more open habitats, then contract into preferred habitats for nesting.