Estimating the size of the Andean Condor population in the Apolobamba Mountains of Bolivia

ABSTRACT.   Population estimates of Andean Condors ( Vultur gryphus ) are urgently needed across their range to more accurately assess their conservation status and design appropriate conservation measures. From July to September 2005, six feeding stations in the Apolobamba mountain range of Bolivia were monitored for 3 days each and all visiting condors were digitally photographed and video-taped. Using distinctive marks, the size and shape of crests, and plumage patterns, we were able to individually recognize 23 adult male Andean Condors, or 30% of all observed condors. By extrapolation, we estimated a minimum population size for Apolobamba during the sampling period of 78 condors. Considering that the current estimate of the total population of Andean Condors in Colombia is 180 individuals, our results illustrate the importance of Apolobamba for Andean Condors and the potential importance of the Bolivian Andes for the conservation of this species. The methods we used to attract, observe, photograph, videotape, and recognize adult males may be useful for other populations of Andean Condors, as well as for other species of threatened vultures.