Year-Round Abundance, Richness and Nesting of the Bird Assemblage of Tall Grasslands in the South-East Pampas Region, Argentina

Summary. One of the most extensive grassland ecosystems in the Neotropics is located in the southeastern South America region. Here grasslands once dominated the Pampas but these are now mostly reduced to a mosaic of patches with different land-uses, largely croplands and pasturelands. Native Cortaderia selloana grasslands are widely distributed in the eastern Pampas region but relatively little is known of the bird assemblage inhabiting this habitat. We studied this bird assemblage addressing the overall richness and presence of species of conservation concern, seasonal variation in species composition, breeding phenology and the importance of C. selloana habitats for birds. Species richness was high: 54 species belonging to 22 families, including six species of conservation concern: three classified as vulnerable to extinction (dot-winged crake Porzana spiloptera, black-and-white monjita Xolmis dominicanus and pampas meadowlark Sturnella defilippii), and three near threatened (greater rhea Rhea american...