DAVAO CITY—Scientists on migratory-bird monitoring have validated a report of a government conservation center in Sarangani that, indeed, lying along the migratory and roosting path of migratory birds from cooler northern regions of Asia, are as many as 86,000 raptors alone from mainland Asia.
In one day alone, on September 29, a team from the Environmental Conservation and Protection Center (ECPC) counted 54,000 raptors in the routine daylong watch from a promontory, called Raptor Hill, in Barangay Rio del Pilar in Glan, Sarangani, the information office of the province said. The place is 200 kilometers south of here.
The ECPC was conducting this year’s migratory-raptor study as the season of bird migration has began. The birds avoid the cold autumn season in cooler parts of the world. The team was assisted by personnel from the Sarangani Information Office and village volunteers.
“It appears that the peak season is here. Today, our team at the Raptor Hill counted around 54,000 Chinese sparrowhawks,” said lawyer Emma Nebran, former executive director of ECPC. “Like clock, the raptors are back.”
Serafin Ramos Jr., Sarangani chief information officer who went with the team, said when the observation entered its two weeks into the watch, “the Sarangani Team has recorded 86,000 raptors, a record-breaking count compared to last year’s 78,817 over five weeks of a confirmatory raptor migration study.”
The birds are looking for thermal air currents, which can be found on Mount Latian Complex, the possible roosting site of such raptors, the team said.
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. Raptor Hill is part of the complex. The presence of migratory birds in Glan was first discovered in 2014, Ramos said, quoting Nebran.
Some residents around Raptor Hill have noticed a “thick flock of birds covering the sun, flying together,” Nebran added.
“The autumn raptor migration study in Sarangani Province was first conducted in 2014 by Alex Tiongco and Maria Teresa Cervero, who reported that Sarangani is very likely a major migration route in autumn for raptors crossing from the Philippines to Indonesia,” Nebran said.
He added: “To validate the report, the provincial government of Sarangani through the ECPC and Raptorwatch Network Philippines conducted last year the autumn raptor migration study from September 15 to October 23 in Glan. The study wanted to establish a database of species, numbers and routes of migrating raptors and locate roosting sites.”
“A total of 78,817 migratory raptors composing of seven species were counted. The study proved that Sarangani Province is indeed a major autumn migration route for raptors crossing from the Philippines to Indonesia,” Nearby said.
For 2017, the autumn raptor migration study was started on September 18 and would last up to October 31 in and around Raptor Hill, Ramos said.
“Researchers from the Japanese Society for the Conservation of Birds are expected to join the Sarangani Team,” Nebran added.
The monthlong study aimed to promote coordinated actions to achieve and maintain the favorable conservation status of migratory raptors; to protect these migratory species along their flyways and to identify their important habitats, roosting sites and favored routes; and to produce a relevant research.
In last year’s study, Ramos said the Raptorwatch Network and the Sarangani Team conducted a confirmatory raptor migration study in from September 15 to October 22.
The team conducted site reconnaissance for the arrival of the migratory birds of prey as they approach the Philippines in September and October to warm up and look for roosting sites after leaving Taiwan.
Filipino scientists said migration of the raptors “is a particularly sensitive indicator of environmental health, which would draw the interest of tourists and wildlife enthusiasts. Conducting long-term counts of migrating raptors can help in the study of their migration patterns, behaviors and populations.”
The raptors arrive in Sarangani twice a year; September to October and March to April, their return flight. Raptors are characterized by their sharp vision that allows them to detect prey during flight. They usually feed on rats and insects. Thus, they serve as natural pest control in the area.
Studies and in-depth monitoring have been done in Indonesia and Taiwan. Quoting the team, Ramos said one theory “states that Sarangani might be their exit point going to Indonesia and could be the major flyway.”
An earlier study, “Project Southern Crossing 2014: First observations of autumn raptor migration at Sarangani, Mindanao, Philippines,” by Tiongco and Cervero, Adrian M. Constantino and Maria Katrina C. Constantino, described the Philippines as an “important link in the East Asia-Australasian Flyway, a migration route involving long sea crossings,” BirdLife International 2015 said.
According to the study, in autumn and spring, thousands of raptors pass through the Philippines; some are believed to winter in the country.
“In autumn, the birds fly south from the Palearctic breeding areas, passing across southeast China and Taiwan before arriving on Luzon en route to wintering areas further south,” the 2014 study said.
The 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 [adjacent to Barangay Rio del Pilar] 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 (eight), crested honey buzzard (14), Chinese sparrowhawk (47,307), Japanese sparrowhawk (two), grey-faced buzzard(242) and peregrine falcon (two).
Resident species observed were Philippine serpent eagle (five), South Philippine (Pinsker’s) hawk-eagle (28) and Brahminy kite (60). Unidentified falcons (four) and other raptors (six) were also observed.
The Chinese sparrowhawk was the predominant species, comprising 99 percent of the raptors observed
The study suggested that Sarangani “is very likely to be a major migration route in autumn for raptors crossing from the Philippines to Sulawesi,” Ramos said.
Image credits: Wikimedia Commons