There are seven recognized subspecies:
- C. c. achrustera (Peters, 1923) – San Lucas California quail – southern Baja California
- C. c. brunnescens (Ridgway, 1884) – extreme northern costal California to southern Santa Cruz County
- C. c. californica (Shaw, 1798) – northern Oregon and western Nevada to southern California and Coronado Islands
- C. c. canfieldae (Van Rossem, 1939) – Owen Valley quail – Owens Valley of east central California
- C. c. catalinensis (Grinnell, 1906) – Santa Catalina quail – Santa Catalina Island (off southern California)
- C. c. orecta (Oberholser, 1932) – Warner Valley quail – Warner Valley in Oregon to extreme northern California
- C. c. plumbea (Grinnell, 1926) – San Quintin California quail – San Diego County to southern Baja California
They are year-round residents. Although this bird coexists well at the edges of urban areas, it is declining in some areas as human populations increase. They were originally found mainly in the southwestern United States but they have been introduced into other areas including British Columbia, Hawaii, Chile, Uruguay, Brazil, Argentina, Peru, South Africa, New Zealand, and to Norfolk Island and King Island in Australia. These birds forage on the ground, often scratching at the soil. They can sometimes be seen feeding at the sides of roads. Their diet consists mainly of seeds and leaves, but they also eat some berries and insects; for example, Toyon berries are a common food source. If startled, these birds explode into short rapid flight, called "flushing". Given a choice, they will normally escape on foot.
Their breeding habitat is shrubby areas and open woodlands in western North America. The nest is a shallow scrape lined with vegetation on the ground beneath a shrub or other cover. The female usually lays approximately twelve eggs. Once hatched, the young associate with both adults. Often, families group together, into multifamily "communal broods" which include at least two females, multiple males and many offspring. Males associated with families are not always the genetic fathers. In good years, females will lay more than one clutch, leaving the hatched young with the associated male and laying a new clutch, often with a different associated male.
They have a variety of vocalizations including the social "chicago" call, contact "pips" and warning "pips". During the breeding season, males utter the agonistic "squill" and will often interrupt their social mate's "chicago" call with a "squill," a possible form of antiphonal calling.