The identification of key areas for conservation and protection according to science-based evidence is an important component to circumvent the negative impacts of environmental changes within geopolitical territories and across the globe.  Priority areas for biodiversity played an important role to ensure the protection of many species particularly those that are unique and threatened.  There are more than 200 Key Biodiversity Areas (KBAs) in the Philippines, yet many important research and biodiversity data are either unpublished or unconsolidated.  Birds are commonly studied indicators for KBA identification due to their high species richness, diversity, and sensitivity to forest ecosystems.  By combining data from past and present surveys, we accounted for a total of 148 bird species of 51 families, with 20 new records from recent field surveys.  Our analysis showed a high level of endemism within Mt. Hilong-hilong with 36% Philippine endemic, 14% restricted to Mindanao faunal region and 11% migrant. In terms of conservation, 8% of the species were considered in threatened categories.  The species richness and endemism were higher in lowland to mid-elevation areas compared to higher elevation areas of the KBA.  Endemism (i.e., Mindanao endemic) and increasing body mass were important determinants of binary extinction risk for bird species in Mt. Hilong-hilong.  The high biodiversity in Mt. Hilong-hilong indicates an example of the vital role of KBAs in preserving nationally and globally important bird species.  Lastly, we emphasise the importance of collaboration and integrating past and present information to synthesise relevant information to complement ongoing conservation efforts in Mt. Hilong-hilong and other key habitats in the Philippines.