The Busa Mountain Range hosts one of the last remaining forests in southern Mindanao, Philippines. Previous bird surveys were confined only to the northern slope, leaving the southern slope in Sarangani Province a relatively understudied area in terms of avian fauna. To augment this gap, we did a rapid inventory survey of bird presence in the Busa Mountain Range employing a combination of line transects, point counts, opportunistic listing, and observation from vantage points, which were supplemented by secondary data from a previous avifaunal assessment. We recorded a total of 116 bird species from 45 families and 88 genera. Despite the significant number in species tally, our survey of birds in the Busa Mountain Range is still inadequate because of the few field sites visited (10 localities) and limited survey time for each locality (82.85 person-hr on average). The presence of several threatened species (DAO 2019- 09: 16.37%, n= 19; IUCN V3.1: 13.79%, n= 16), endemic species (53.44%), and anthropogenic disturbance indicate the strong need for protection of the bird fauna and their habitats in the Busa Mountain Range.

The Mindanao treeshrew (Tupaia everetti Thomas, 1892) is an endemic non-volant mammal species found in the Mindanao Faunal Region in the Philippines. The nest architecture and nest site characteristics of T. everetti are described for the first time based on a single active nest documented from Dinagat Islands. The nest was on the ground, built inside a cavity of a dead pandan tree (Sararanga cf. philippinensis), and was surrounded by natural vegetation. This nest discovery is a valuable contribution to the minimal existing literature about this poorly studied species, which may be increasingly threatened by anthropogenic impacts. As such, we highly recommend more nest search and breeding ecology studies on Dinagat islands and other areas where T. everetti is found to determine if the nesting pattern is similar to what was discovered in this study.

Current knowledge of flower visitors and pollination of the Philippine lipstick vine species (Aeschynanthus cf. leucothamnos) has not been properly documented. Here, we report the first photographic evidence of floral visitation by a naked-faced spiderhunter (Arachnothera clarae) on A. cf. leucothmnos from Burauen, Leyte, Philippines. We also describe the bird’s foraging behavior and its potential as a pollinator of the lipstick vine genus Aeschynanthus.