We studied the species composition and seasonality of the bird community in the semi-arid west pampa grasslands of Argentina. The study was carried out in natural grasslands with and without a history of cattle grazing (“mixed grassland” and “sorgastral,” respectively). We counted birds using the strip-transect method. We recorded a total of 22 bird species including only 12 grassland-dependent species. The more representative species of these grasslands were Chaco Pipit (Anthus chacoensis), Long-tailed Meadowlark (Sturnella loyca), and Grassland Sparrow (Ammodramus humeralis). Richness and abundance of birds were higher in mixed grasslands than in sorgastral in spring and summer, but not in winter. Inside habitats, richness and abundance were higher in spring and summer than in winter. We observed a seasonal change in guild dominance, with granivores dominant in winter, although bird density decreased during winter for all guilds. Despite the low richness recorded, the presence of certain rare species, such as the Chaco Pipit and the near threatened Greater Rhea (Rhea americana), add conservation value to west pampa grasslands.