Many of the species that breed in shortgrass prairie winter in vast numbers in the grassland portion of northern Mexico's Central Plateau. Conservation efforts directed solely at the breeding grounds of grassland birds in the U.S. could prove fruitless if consideration is not given to the importance of the wintering grounds of this group of birds. Grassland experts have hypothesized that winter grounds may play an important role in the population declines experienced by these species. RMBO has conducted several research projects on the Central Mexican Plateau studying several species of grassland birds such as Long-billed Curlew, Burrowing Owl, Cassin's Sparrow, and Baird's Sparrow.