The California Towhee is a large, plainly marked ground-sparrow showing no sexual color dimorphism. Demonstrating wide geographic and ecological breadth, this sedentary inhabitant of low vegetation forages mostly on the ground and occurs widely from semiarid upland to moist riparian habitats. It is a permanent resident from southern Oregon south throughout most of the Upper and Lower Sonoran zones of California to the tropical tip of Baja California. One of the commonest and best known of California birds, it is tolerant of rural development and urbanization.
For many years the California Towhee was treated conspecifically under the name Pipilo fuscus (Brown Towhee) with the allopatric Canyon Towhee (Melozone fuscus), the latter occurring east of the Colorado River into tropical mainland Mexico. Similarities between southern races of M. crissalis and M. fuscus that were used in the rationale for combining the 2 species may be at least partially the result of parallel evolution in arid regions rather than a reflection of common ancestry. In several ways, the California Towhee also resembles the Abert's Towhee (M. aberti): in appearance, in its relatively unmelodious songs, and in its use of metropolitan area habitat. The California Towhee, however, is geographically and ecologically much more widely distributed than Abert's Towhee, which occurs in more mesic southwestern riparian habitats.
The California, Canyon, Abert's and White-throated (M. albicollis) towhees, collectively known as “brown towhees,” provide a much-studied model for avian speciation; see Systematics. This was pointed out by Davis ( Davis 1951a ), and more recently, genetic studies have added new evidence to the century-old conflict regarding the relationship of California Towhee to Canyon Towhee and other species (see Zink 1988 , Zink and Dittman 1991 , Dodge et al. 1995 , Zink et al. 1997, DaCosta et al. 2009). Genetic evidence indicates that the California Towhee is, in fact, more closely related to the Abert's Towhee (Melozone aberti) (and possibly to the White-throated Towhee (Melozone albicollis)) than it is to the Canyon Towhee (Zink 1997, DaCosta et al. 2009). Phylogenetic studies have also led to the re-classification of these four formerly Pipilo species into the genus Melozone (Chesser et al. 2010).
The California Towhee is a characteristic bird of chaparral and underbrush in oak woodland, generally occurring in wetter habitats than the Canyon Towhee, which is largely a desert-scrub and semidesert grass-land species. The California Towhee occupies rugged, remote back-country habitats like the Canyon Towhee but also commonly occurs in shrubby vegetation of densely populated urban and suburban areas, habitats shunned by the Canyon Towhee. The Inyo California Towhee (M. c. eremophilus), with an endemic population of approximately 700 individuals, occurs in riparian habitat of the arid Argus Mountains of central-eastern California. In 1987 it was classified as Threatened and critical habitat was designated by the U.S. Fish and Wildlife Service ( U.S. Fish and Wildlife Service 1987b ). Protection measures led to an increase in population size and a recommendation for delisting in 2008 (U.S. Fish and Wildlife Service 2008).
Most published studies of the California towhee have been conducted in the vicinity of Berkeley, Carmel Valley, and Los Angeles, California. The most extensive work, touching on most known aspects of the species, is found in Davis' ( Davis 1951a ) thorough monograph. Vocalizations have been studied intensively by Quaintance ( Quaintance 1938 , Quaintance 1941 ) Marshall ( Marshall 1964c ) (who also provided comparative information for brown towhees (Marshall Marshall 1960 , Marshall 1964c )), and Benedict (2010). Childs ( Childs 1968g ) and Benedict (2008, 2009) reported breeding and other life-history information from studies using banded individuals. The only known food analysis was during the early 1900s ( Beal 1910 ), referenced by Davis ( Davis 1951a ).