Philippine Journal of Science 150 (S1): 347-362, Special Issue on Biodiversity ISSN 0031 - 7683 Date Received: 28 Sep 2020 Bird Observations in the Busa Mountain Range, Sarangani Province, Philippines Tristan Luap P. Senarillos1*, Kier Mitchel E. Pitogo2, and Jayson C. Ibañez1 1Philippine Eagle Foundation Inc, Philippine Eagle Center Malagos, Baguio District, Davao City 8000 Philippines 2Department of Environment and Natural Resources Provincial Environment and Natural Resources Office South Cotabato Block 1, Martinez Subdivision, Koronadal City 9506 Philippines 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. Keywords: bird conservation, bird diversity, Mount Busa, Philippine eagle critical habitat, rapid survey, species checklist INTRODUCTION conversion for agriculture and settlements, the remaining forest block in southern Mindanao is mostly confined The Busa Mountain Range is a key biodiversity area (KBA to these mountains (Namocatcat et al. 2015; DENR 116) and an extremely high conservation priority site in 2020). Recently, the mountain massif was declared as a the Philippines (Ong et al. 2002). It was also identified as local conservation area (LCA) by virtue of Resolution an important bird area for holding a significant number of No. 2020-10-042 passed by the Provincial Council of globally threatened and restricted-range species (Criteria Sarangani on 10 Mar 2020 as a step towards establishing A1 and Criteria A2, respectively; BirdLife International a long-term legal framework for the protection of the 2020a). The KBA 116 comprises the coastal range of the mountain range (Peralta 2020). mountains in Sarangani and South Cotabato Provinces that include the Mounts Busa, Three Kings (Talili), and The shared forests of Sarangani and South Cotabato Parker (Melibengoy). With the pressures brought by forest Provinces are a mix of secondary-growth, primary lowland evergreen, and lower and upper (mossy) *Corresponding Author: [email protected] montane forests that serve as critical watershed areas for 347 Philippine Journal of Science Senarillos et al.: Birds of Busa Mountain Vol. 150 No. S1, Special Issue on Biodiversity Range, Sarangani, Philippines the low-lying communities and habitats for threatened Site 2: Sitio Angko, Brgy. Batian, Maitum (6.155528° and restricted-range species of birds and other wildlife 124.491590°; 495 masl). This area is characterized by a (BirdLife International 2020a; Namocatcat et al. 2015; mix of shrubland, grassland, and agricultural areas. Forest DENR 2020). In the previous ornithological surveys and in the area was cleared to established settlements and collecting expeditions, assessments were only limited “kaingin” (slash-and-burn) farms. The abandoned kaingin to the Lake Sebu side of the mountain range (Dickinson farms were colonized by the highly invasive “buyo-buyo” et al. 1991; Robson and Davidson 1996; Kennedy et al. (Piper adduncum). 2000), making the remaining areas – particularly the southern slope in Sarangani – one of the least explored bird Site 3: Tambusong, Brgy. Batian, Maitum (6.168910° habitats in the Philippines. For this reason, the knowledge 124.499500°; 384 masl). This site is an open area located regarding bird species diversity in the Busa Mountain on a ridge top bounded on both sides by steep ravines and Range remains fragmented and minimal. has a good vantage view of the adjacent natural forest. It is composed primarily of cultivated areas for corn, upland To address current gaps, the Philippine Eagle Foundation rice, coconut, and scrubland, which is also used by local (PEF) together with the Department of Environment and communities for grazing their livestock. While patches Natural Resources Region 12 (DENR RXII) listed bird of riparian forest habitat are present on the lower slope species found within the Philippine Eagle survey sites in of the ridge that is dominated by a mixture of primary the Busa Mountain Range. This initial attempt generated forest trees. the first comprehensive list of birds occurring in the mountain range and provided preliminary information on Site 4: Sankil, Brgy, Batian, Maitum (6.166390° bird species that are regarded as globally important due to 124.522830°; 647 masl). This site is a transitional upper their endemism and conservation status. The availability evergreen forest. The observation post was established on of this updated ecological data is essential as a springboard an abandoned logging trail as a result of the destruction for setting conservation initiatives within this priority of the primary forest in the 1980s. What remained now conservation area. are old trees that were left by logging and new ones that have grown after the logging concession. Of all our survey sites in Maitum, this is the closest site to the pristine forest habitat in the Busa Mountain Range. METHODS Site 5: Sitio Boting, Brgy. Batian, Maitum (6.154700° 124.518460°; 294 masl). Sitio Boting is an inland Study Areas community located next to Boting river. The area is The southern slope of the Busa Mountain Range in landlocked by gorges and slopes. Much of the vegetation Sarangani Province is politically bordered by three in this area is similar to Site 1 whereby cleared areas municipalities – Maasim on the east, Kiamba at the mid- are planted with corn, coconut, and upland rice. Some center, and Maitum on the far west of the mountain range. portions of the forest are planted with “falcata” for timber Field visits were made to different forested localities harvesting. in Maitum and Kiamba (Table 1). At present, the PEF, Site 6: Lamlunay, Brgy. Upo, Maitum (6.11377° DENR RXII, and the Municipal Local Government Unit of 124.464789°; 60 masl). Lamlunay is a fragment of Maitum (MLGU Maitum) are closely working together to lowland evergreen forest separated by cultivated areas. declare the areas covered under the jurisdiction of Maitum The site is dominated by emergent trees such as “dao” as a Philippine eagle critical habitat (PECH), since these (Dracontomelon dao), “yakal” (Shorea astylosa), and are both important hunting ground and nesting areas for “tanguile” (Shorea polysperma). Various species of the critically endangered Philippine eagle (Pithecophaga fruiting Ficus were also found to be abundant along the jefferyi) and are outside the declared KBA and LCA side of the stream. The forest floor in this area is thick in boundaries (Figure 1). dried leaf litters. Site 1: Barangay Batian Sentro, Maitum (6.141670° Site 7: Sitio Tulad, Brgy. Nalus, Kiamba (6.084166667° 124.514086°; 98 masl). This area is a low-lying 124.6511667°; 618 masl). The area is a mixed advanced community surrounded by undulating slopes of secondary secondary lowland evergreen forest with primary forest and primary lowland evergreen forest. Much of the patches mostly concentrated along riparian corridors and forested areas were cleared to give way for agriculture. in steep areas. The village is at the immediate base of Mt. The Batian river on the west and Boting river on the east Busa which is the merging point of two major streams confluence together in this area, which forms the Kalaneg flowing from the mountain down to the Panguil River. river that meanders on the community in the lowlands of Maitum. Site 8: Mt. Busa, Kiamba (6.105833333° 124.68195°; 348 Philippine Journal of Science Senarillos et al.: Birds of Busa Mountain Vol. 150 No. S1, Special Issue on Biodiversity Range, Sarangani, Philippines Table 1. Survey sites within the Busa Mountain Range, Sarangani Province, Philippines. Locality Coordinates Elevation Survey period Barangay Batian Sentro, 6.141670° 124.514086° 98 masl 8–10 Aug 2018 Maitum Sitio Angko, Brgy. Batian, 6.155528° 124.491590° 495 masl 20–21 Jun 2020 Maitum Tambusong, Brgy. Batian, 6.168910° 124.499500° 384 masl 22–23 Jun 2020 Maitum Sankil, Brgy Batian, Maitum 6.166390° 124.522830° 647 masl 26–30 Jun 2020 Sitio Boting, Brgy. Batian, 6.154700° 124.518460° 294 masl 1–5 Jul 2020 Maitum Lamlunay, Brgy. Upo, Maitum 6.11377° 124.464789° 60 masl 11–12 Aug 2018 Sitio Tulad, Brgy. Nalus, 6.084166667° 124.6511667° 618 masl 6–8 Aug 2020 Kiamba Mt. Busa, Kiamba 6.105833333° 124.68195° 1,830 masl 9—11 Aug 2020 Sitio Banate, Brgy. Badtasan, 6.069966667° 124.6386333° 427 masl 12–13 Aug 2020 Kiamba Sitio Datal Bong, Brgy. 6.069533333° 124.6572167° 751 masl 13–14 Aug 2020 Tamadang, Kiamba Figure 1. Map of the Busa Mountain Range showing the relative location of the study sites inside and outside the KBA 116. 349 Philippine Journal of Science Senarillos et al.: Birds of Busa Mountain Vol. 150 No. S1, Special Issue on Biodiversity Range, Sarangani, Philippines 1,830 masl). The area is the upper montane forest of Mt. RESULTS Busa, Kiamba. It is characterized by a mix of stunted and tall hardwood trees. The forest floor is mostly covered A total of 116 species of birds were recorded for the with moss, bryophytes, and moist thick leaf litter.