The original 24,900 km2 distribution of the Cauca Guan Penelope perspicax is currently reduced to less than 750 km2. In addition, forest within this range is fragmented and populations are isolated. We conducted surveys to determine the presence of the Cauca Guan at several locations within its present range, and mapped all known localities with guan records. Cauca Guan populations are confirmed to occur at only four sites, and the guan is absent from several localities with historic records. Some sites where the Cauca Guan is potentially present are highlighted. In particular, the possible existence of populations on the Pacific slope of the Andes requires confirmation, since a large habitat block is available. Population density estimates were obtained in two protected areas. In Yotoco Forest Reserve (559 ha) we estimated 8.6 guans km−2. At Otún-Quimbaya Flora and Fauna Sanctuary (489 ha), guans fed seasonally on leaves of Chinese ash Fraxinus chinensis, an exotic tree planted in a revegetation programme. Seasonal densities in ash plantations were over 100 guans km−2, whereas in mixed forest, mean density was 41.6 birds km−2. Ash has apparently become a key resource for this population. Although these two populations are within protected areas and have relatively high densities, they are small and isolated and require continued monitoring.