Mountain Quail (Oreortyx pictus) populations have declined in many areas of the western Great Basin during the past century. Yet the life history of this species is little known. From 1997 to 2000, I studied radio-marked Mountain Quail in Hell's Canyon in northeastern Oregon, in the Cascade Mountains of southwestern Oregon, and a translocated sample of quail captured in the Cascades and released in Hell's Canyon. I monitored 252 radio-marked quail to determine reproductive characteristics, survival rates, habitat associations, and diets. Mountain Quail employed 2 strategies in selecting breeding sites, they remained in winter ranges to breed or migrated 1.5-30 km to new breeding ranges. Of 34 nests found in northeastern Oregon most were associated with coniferous forests and understories dominated by snowberry (Symphoricarpos albus) and mallow ninebark (Physocarpus malvaceus). In southwestern Oregon, nests (n = 23) were generally located in early-seral (shrub-sapling) vegetation. Shrub height, shrub density, and canopy closure were greater at nest sites than at random plots. Nearly 50% of the nests were incubated exclusively by males. In addition to incubation, males appeared to be nearly full partners in brood rearing, and males had similar clutch and brood sizes and earlier hatch dates than females. I observed 6 females that produced 2 simultaneous clutches; males and females of each pair incubated separate clutches. Nest attendance patterns were similar for males and females, but quail in Hell's Canyon were on nests longer before absences, and quail in the Cascade Mountains were more frequently absent during early morning. Survival rates were similar for native and translocated quail in Hell's Canyon and the Cascades, but males had higher survival rates than females. Mountain Quail in Hell's Canyon were mostly located in plant communities found on moderate to steep slopes, with an overstory dominated by conifers {Douglas-fir (Pseudotsuga menziesi) and ponderosas pine (Pinus ponderosa)}, and understories dominated by snowberry, mallow ninebark, or dogwood (Cornus spp.). In southwestern Oregon, most Mountain Quail observations were in early-seral, successional shrub/sapling stands. In the Cascades during the fall and winter Mountain Quail used many different food resources, but their diets were composed primarily of legumes.