Avifaunal inventories in 1980, 2007 and 2009 along the eastern slope of the Peruvian Andes at Abra Maruncunca, dpto. Puno, document the occurrence and change in relative abundance of 245 species. Degradation of forest cover with an increase in secondary vegetation probably explains many of the differences between the 1980 and 2009 surveys. We provide details for the first occurrence and clarification of the status in Peru for Ochre-cheeked Spinetail Synallaxis scutata, Olivaceous Woodcreeper Sittasomus griseicapillus viridis, Scimitar-winged Piha Lipaugus uropygialis, White-necked Thrush Turdus albicollis contemptus, Bluebrowed Tanager Tangara cyanotis cyanotis, White-browed Brush Finch Arremon torquatus and Yellow-bellied Siskin Sporagra xanthogastra, with comments on the taxonomy of Roadside Hawk Rupornis magnirostris, Plumbeous Pigeon Patagioenas plumbea, a Pyrrhura parakeet, White-bellied Hummingbird Amazilia chionogaster, an antwren Herpsilochmus sp., and Fuscous Flycatcher Cnemotriccus fiiscatus. The key for ensuring that this rich avifauna is preserved at this site lies in the protection of the relatively intact forest at the base of the massif at the north end of our study area. © 2013 British Ornithologists' Club.