Serranía de Perijá is the northernmost projection of the Andes. Although it has a distinct orogenic history from the adjacent ranges of northern South America, Perijá has received little biological research and conservation attention, particularly on the Colombian side. The avifauna of Serranía de Perijá remains understudied and its populations are often not included in bio-geographic studies or taxonomic revisions. Here we present the results of two ornithological expeditions carried out in 2008 and 2009 in along the western (Colombian) slope of this range, from between 1500 to 3100 m. We recorded 182 bird spe-cies in montane forests and paramo habitats. Combining historical records from museum collections and the literature with our findings resulted in at least 425 species recorded to date in this range above 800 m. We discuss novel information on distribution and natural history and underscore intriguing patterns of geographic variation and endemism of selected Perijá taxa. Our study has implications for understanding the diversity of birds of the Northern Andes and urges for research and conservation actions of the remaining montane forests and paramo of Serranía de Perijá. © 2015, Asociacion Colombiana de Ornitologia. All rights reserved.