We provide an updated checklist of birds of a unique landscape in northeastern Argentina, which is characterized by three isolated, rocky outcrops and their surrounding agroecosystem. We recorded 188 bird species, including nine that are globally or nationally threatened. We highlight the presence of several grassland-specialist birds of conservation concern. Of the species recorded, 80.6% are residents and 17.7% are migrants. The heterogeneity of the landscape and its structural complexity accounts the existence of a high avian species diversity, which includes both generalists and specialists. This study confirms the conservation value of this ecosystem, due both to the rocky outcrops and grassland matrix. Grasslands are one of the most threatened biomes in the world.