The main ecosystem in northern Patagonia, Argentina, is the Monte, a semi-desert scrubland home to a high biodiversity. Monte is the most endangered ecosystem of southern South America, with an annual rate of clearance of the native vegetation estimated at 3.7%. Here we report the results of bird surveys carried out in the province of Río Negro, ... northern Patagonia. We surveyed four localities mostly dominated by the Monte ecosystem, between 1986 and 2010. Three localities are Important Bird Areas (IBAs): El Cóndor, San Antonio Oeste and Meseta de Somuncurá. The fourth locality is the Paso Córdoba nature reserve. We recorded a total of 263 bird species. The highest species richness was observed at San Antonio Oeste, followed by El Cóndor. Information regarding the period of occurrence and habitats are provided for all species and localities. Additionally, we indicated the cases in which breeding behavior was observed. This information is urgently needed for the evaluation of the consequences of habitat destruction and deterioration as well as for the success of intended remediation measures.