In this study we compared bird species inventories from ornithological collections of San Pedro de los Milagros (Antioquia) and the results of recent rapid assessment fieldwork in the municipality. San Pedro is the type locality of Atlapetes blancae, a critically endangered bird species. Of the 155 bird species recorded in the municipality was presented, including 148 bird species recorded during fieldwork. In contrast, 43 species were recorded from ornithological collections, highlighting the importance and effectiveness of rapid assessment surveys. Nonetheless, seven species represented in collections were not recorded during fieldwork, for which possible explanations are discussed. It is suggested that the search for Atlapetes blancae should be carried out in other habitats and regions in northern Antioquia, as it we did not find it during fieldwork. Various new distributional records from fieldwork are also discussed.