DAVAO CITY—The Wild Bird Club of the Philippines (WBCP) and the Sarangani provincial government are set to conduct a study to confirm that Sarangani is a migratory flyway or roosting site of birds escaping the autumn and winter cold of northern countries.
The WBCP would be joined in the study by the province’s technical working group (TWG) from September 15 to October 22, the provincial information office said. The province’s Environmental Conservation and Protection Center (ECPC) has conducted site reconnaissance for the arrival of the migratory birds of prey this month. The center serves as the secretariat of the technical working group.
The study was prompted by the pattern of swarm of birds not endemic to the Philippines during the last quarter of the year, the period of autumn season in the Northern Hemisphere.
The presence of migratory birds in the municipality of Glan was first noticed in 2014, and again in March this year. Lawyer Emma Nebran, ECPC executive director, said the birds arrive in the province twice a year, in September and October, and in March and April.
“Some residents in Barangay Cross have noticed a thick flock of birds covering the sun, flying together,” she said. Nebram said some of the birds were also seen in Barangay New Aklan. “If they will be here, we would not be surprised, because we prepared ahead of time,” according to the information office, quoting New Aklan Barangay Chairman Victorio Salutan.
Felix Servita of the WBCP said the migration of the raptors is an indicator of the “sensitive environmental health of their target nesting or resting sites.”
He said the autumn migration is likely to proceed to Indonesia, “but they will approach our country in September and October to warm up and look for roosting sites after leaving Taiwan.”
Servita said the birds have been noticed to favor the Latian Complex, especially in Mount Gulo, where he suspected was an area of possible roosting site of the raptors. He added that the Latian Complex contain the desired thermal air currents for bird flight.
Mount Latian Complex has been identified as one of the important biodiversity areas in the Philippines. In 2002 it was declared by the Department of Environment and Natural Resources as Philippine Biodiversity Conservation priority, the information office said. The area covers the Sarangani towns of Malungon, Alabel, Malapatan and Glan, and their adjacent Davao Occidental municipalities of Jose Abad Santos, Malita and Don Marcelino.
Nebran said, “In spots where the ground is warm, the air rises, forming thermal currents. Raptors find these thermals and spiral upward without having to flap their wings. It helps them travel long distances without using much energy. Raptors stick to the mountains because of thermals.”
“Hence, conducting long-term counts of migrating raptors can help in the study of their migration patterns, behaviors and populations,” the bird group and the ECPC said. The information office disclosed that the ECPC has made reconnaissance of the best bird-watching sites and identified Barangay Laguimit as the best site. “They are not really monitored in our country. But studies and in-depth monitoring were done in Indonesia and Taiwan,” Servita said. “One theory states that Sarangani might be their exit point going to Indonesia and could be the major flyway.”
The ECPC, the TWG and the WBCP will conduct the monthlong study that aims to promote coordinated actions to achieve and maintain the favorable conservation status of migratory raptors; to protect the migratory species along their flyways; to identify their important habitats, roosting sites and favored routes; and to produce a relevant research.
The information office said there was an earlier study in the migratory birds in the area. Titled “Project Southern Crossing 2014: First Observations of Autumn raptor Migration at Sarangani, Mindanao, Philippines,” the report’s authors were Alex M. Tiongco, Maria Teresa A. Cervero, Adrian M. Constantino and Maria Katrina C. Constantino. It described the Philippines as an “important link in the East Asia-Australasian Flyway, a migration route involving long sea crossings.” According to the study, in autumn and spring, thousands of raptors pass through the Philippines; some are believed in the country in winter, the information office said.
“In autumn, the birds fly south from the Palearctic breeding areas, passing across southeast China and Taiwan before arriving in Luzon en route to wintering areas further South.”
The WBCP Raptor Study Group (RSG) has made exploratory expeditions to map the migratory routes through the country, including entry and exit points.
“During the 2014 autumn migration, the RSG decided to work in the Davao del Sur and Sarangani area,” the study said.
“Initial observations in [Barangay] Cross revealed a passage of migrants from Mount Gulo and nearby roosting areas with the vantage point directly below the migration path,” it added.
In all, nine raptor species were seen during the watch, six migrants and three residents. The migrant species seen were (Western) Osprey Pandion haliaetus (8); Crested Honey Buzzard (14); Chinese Sparrowhawk (47,307); Japanese Sparrowhawk (2); Gray-faced Buzzard (242); and Peregrine Falcon (2).
Resident species observed were Philippine Serpent Eagle (5); South Philippine (Pinsker’s) Hawk-eagle (28); and Brahminy Kite (60). Unidentified falcons (4) and other raptors (6) were also observed.
Chinese Sparrowhawk was the predominant species, comprising 99 percent of the raptors observed, the information office said.
The study suggested that Sarangani “is very likely to be a major migration route in autumn for raptors crossing from the Philippines to Sulawesi.”
Image credits: Jake Narte/Sarangani Information Office