More than a half century of research on northern bobwhites (Colinus virginianus) in south Texas has provided a legacy of information for ecologists and managers. South Texas is a semiarid and subtropical environment with highly variable weather, a land base consisting of large private ranches devoted to livestock production, a perennial problem of brush encroachment on rangelands, and a strong tradition of fee-lease hunting. These physical, biotic, and social conditions focused research efforts on descriptive natural history (ca. 1930-1980) and evaluation of grazing and brush management practices (ca. 1980-1990). By natural evolution of knowledge, these efforts led to the development of unified theory that synthesized descriptive and applied information about bobwhite management (ca. 1990-2000). In the context of grazing on rangeland subject to encroachment by woody plants, descriptive studies focused on bobwhite home ranges, mobility, flight behavior, nesting cover, resting cover, and whistling posts, among other aspects of habitat use and behavior. The purpose of these studies was to determine how different plant structures and communities should be dispersed in space and time to maximize their value as bobwhite habitat. South Texas studies revealed that the dogmatic principle, bobwhites are early successional species, holds poorly in semiarid, subtropical environments. Research in south Texas led to formalization of the usable-space-in-time hypothesis on bobwhite density. The hypothesis states that, within ordinary limits, mean abundance of bobwhites on an area is correlated more strongly with the quantity of permanent cover to which they are adapted and less strongly with (human) perceptions of habitat quality (foods, interspersion, edge, diversity). Space-time seems to be an omnibus variable that can be assessed in a variety of management and ecological settings. In association with highly variable rainfall patterns and amounts in south Texas, bobwhite populations exhibit boom-bust population behavior. Research on the cause-effect process governing booms and busts has led to rejection of hypotheses on phosphorus, calcium, phytoestrogens, vitamin A, macronutrition, water, and stress-related hormones as causally involved in the phenomenon. Heat-mediated variation in productivity remains a viable hypothesis that is, of course, open to challenge. The information legacy from research on bobwhites in south Texas has led to revision of knowledge emanating from the southeastern United States; the revised knowledge better fits bobwhites and other quails that inhabit semiarid environments.