Intensive inventory work on the Mt. Kitanglad massif of north-central Mindanao, Bukidnon Province, Republic of the Philippines, revealed a diverse avifauna. In all, 198 bird species were detected, of which about 172 were likely breeding in the area, placing the mountain among the most diverse sites that have been surveyed in the country. Three migratory species (Luscinia calliope, Turdus chrysolaus, and Motacilla alba) were detected on the island for the first time by contributors to this summary, and known ranges of several species were extended. The massif holds populations of at least 17 of the 18 species narrowly endemic to Mindanao—more than any other site yet studied—as well as almost half the species endemic to the entire Philippine archipelago. Endemic species are concentrated at higher elevations, whereas migrants and widespread species are more frequent in the lowlands. The Kitanglad massif, however, has been modified severely below about 1200 m, with removal of almost all lowland forest habitats. Records and data accumulated by historical collectors, recent collectors, and recent observers are compared and contrasted to reflect on the biases, strengths, and omissions in each. The importance of the Kitanglad region to effective conservation of biodiversity in the southern Philippines is particularly emphasized.