Home range, habitat use, and movements of reintroduced masked bobwhite (Colinus virginianus ridgewayi) were studied during 1986-88 on the Buenos Aires National Wildlife Refuge in southern Arizona. Home ranges averaged 10.9 ha (5.2-14.6 ha), and core areas averaged 1.1 ha (0.2-2.7 ha). Core areas had significantly higher visual obstruction by vegetation from 0-1 dm, aerial and basal grass cover, and significantly lower bare ground, litter, half-shrub cover, half shrub density, and visual obstruction by vegetation from 5-20 dm than non-core areas. The majority of the masked bobwhite moved less than 1 km between their release location and the site of first trapping. However, some long distance movements occurred. Once home ranges were established, masked bobwhite seldom left the boundaries. Key habitat components are identified for masked bobwhite on the Buenos Aires National Wildlife Refuge.