An average of roughly 10,000 ha of grasslands, primarily northern mixed-grass prairie, is treated annually with prescribed fire on the U.S. Department of the Interior’s National Wildlife Refuges (NWRs) in the Dakotas and eastern Montana. This management continues despite sparse information on effects of fire on wildlife, introduced and native plants, and wildlife-habitat relationships in the northern mixed-grass prairie ecosystem. To address basic information gaps, we assessed direct and indirect, short and long term impacts of fire or fire suppression on vegetation and wildlife population dynamics at 4 NWRs in northwestern and north central North Dakota during 1997-2003; most work was conducted at Des Lacs NWR and J. Clark Salyer NWR. Funding from the Joint Fire Science Program during the final 2 years of our work helped us expand the inferential value of our studies while giving land managers a novel chance to more clearly identify opportunities and limitations with prescribed burning in relation to the mission and goals of their respective NWRs. Our chief goals were to document effects of prescribed burning of northern mixed-grass prairie on the abundance, productivity, and nest site selection of migratory birds, especially grassland songbirds; measure influences of major sources of woody fuels and habitat edges (e.g., woodland, cropland, wetland) on occurrences and productivity of common bird species; and assess relationships between fire history and vegetation composition and structure on several spatial and temporal scales. Our study area lies within a cool-season (C3)-dominated, needlegrass-wheatgrass (Stipa-Agropyron) association. However, the contemporary prairie we studied on the NWRs is invaded by introduced, cool-season grasses and native shrubs and trees, as are most other prairie tracts managed by the U.S. Fish and Wildlife Service and other conservation agencies in the northern Great Plains region. We used 2 basic approaches to examine fire effects on vegetation and wildlife. First, we designed short-term (<10 years) field experiments to test specific hypotheses regarding fire effects on vegetation structure, plant community composition, and wildlife abundance and productivity. Secondly, we assessed long-term (60-100 years) changes in plant communities associated with changes in fire disturbance regimes during and after settlement of the region by persons of European descent. To address study objectives, we used standard methods to collect, analyze, and report data.