Growing human populations and rapid ecological changes threaten the sustainability of the middle Rio Grande, a river corridor important to numerous species of wintering, breeding, and migrating waterfowl, shorebirds, and songbirds. We review the vegetational and human history of the middle Rio Grande, substantiate the importance of this system to landbirds in migration, relate patterns and trends of migratory bird populations to variation of stopover habitats, and present new data on stopover habitat use and biology of landbird migrants. We supplemented our review of the literature by evaluating banding and survey data from a new study we implemented on the river in 1994, and we re-analyzed population trend data from unpublished banding records. Analyses of data from Hink and Ohmart (1984) and our own study showed that assemblages of migratory landbirds varied in species richness and abundance among seasons and among cottonwood-willow, mesquite, salt cedar, Russian olive, drainage, and agricultural habitats. Our fat deposition data demonstrated that migrating landbirds use the bosque to replenish energy stores during travel. Stopover along the middle Rio Grande may be especially important for those species that migrate across the Chihuahuan Desert. We suggest that spatial and temporal changes in habitat cover, structure, and composition of the middle Rio Grande bosque have potential to influence habitat use, food availability, health and survival during migration, and ultimately, success of future populations of stopover migrants.