From excavations at the Formative period (3,500 to 900 years old) Chiripa archaeological site on the southern shore of Lake Titicaca on the Bolivian altiplano (elev. 3,820 m), we identified 664 bones that represent 41 extant species of birds. Approximately 80% of the bones are from aquatic species such as coots, grebes, ducks, cormorants, and flamingos. Ten species from the bone sample (a grebe Podiceps occipitalis, cormorant Phalacrocorax brasilianus, goose Chloephaga melanoptera, duck Lophonetta specularoides, falcon Falco peregrinus, coots Fulica gigantea and F. leucoptera, dove Metriopelia aymara, owl Asio flammeus, and trogon Trogon personatus) were not recorded during rigorous bird surveys at Chiripa and elsewhere on the Taraco Peninsula in June-July 1996. One of these species (Trogon personatus) inhabits humid montane forest below 3,400 m elevation, and thus probably was transported by people to Chiripa from distances >80 km away. Each of the other nine species except Fulica leucoptera are known to occur regularly within the Titicaca Basin. The prehistoric data support the hypothesis that the regional composition of most continental Neotropical bird communities, in spite of many local range fluctuations, has been fairly stable over the past several millennia, a period of minor climate change compared to that of glacial-interglacial transitions. A challenge to researchers is to tease out the possible causes of local distributional changes in Neotropical birds, including an evaluation of how prehistoric people may have affected the presence and relative abundance of certain species. Received 3 September 2014. Accepted 27 February 2015.