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Increasing hornbill count in Negros
In what could be an interesting development, the Philippines Biodiversity Conservation Foundation Inc. (PhilBio) reported the increasing number of the Visayan tarictic hornbill in Negros Island.
Lisa Paguntalan, PhilBio executive director, presented the findings of their five-year survey on the Visayan tarictic hornbill during the recent webinar on conservation matters. She said that based on the population density, it is estimated that the population of this hornbill is about 3,564 individuals in three protected areas in Negros – Northern Negros Natural Park, Mount Kanla-on Natural Park, and the Balinsasayao Twin Lakes Natural Park.
This species of hornbill, known to science as Penelopides panini, is already classified endangered and occurs only in Negros and Panay. The recent individual hornbill count has almost doubled the estimate of the International Union for the Conservation of Nature, placed at 1,800 covering both Negros and Panay. The IUCN data was still 2001 and based on the analysis of records and surveys of the Birdlife International.
The Visayan tarictic hornbill usually inhabits lowland forest below 1,200 to 1,500 meters above sea level. It is most likely the reason why the population density of the species is much higher in the NNNP since it has still a large intact lowland forest. The report of the PhilBio claimed that the habitat requirements of the Visayan tarictic hornbill include tree heights of at least 15 meters, and a number of trees with diameter-at-breast of more than 60 centimeters.
The Visayan tarictic hornbill is one of the two species of hornbills that can only be found in Negros and Panay. The other species is the Rufous-headed hornbill (Rhabdotorrhinuswaldeni), which is already classified by the IUCN and the Department of Environment and Natural Resources as critically endangered, the highest level of threat assigned to a species that is facing extreme threat of extinction in the wild. The Rufous-headed hornbill was thought to be extinct in Negros until it was rediscovered in recent years. The PhilBio is still conducting population survey of this species.
The Philippines has been noted for hornbill species diversity. Of the 55 known records of hornbills around the world and 32 in Asia, the country accounts for at least 10 species and all are endemic only in the Philippines. Aside from the two species that occur in Negros and Panay, other endemic hornbills of the Philippines are Sulu hornbill, Mindoro hornbill, Palawan hornbill, Luzon hornbill, Mindanao hornbill, Samar hornbill, Southern rufous hornbill and Mindanao wrinkled hornbill. There are several sub-species of hornbills in the Philippines, like the sub-species of the Visayan tarictic hornbill that has been recorded in Ticao Island, but unfortunately, it is already extinct.
Most of the hornbill species in the Philippines are already listed as threatened species due to habitat conversion and hunting. Most of the lowland forests, where the different species occur, have already been converted into other purposes, primarily agriculture and settlement. The hornbill species density in Negros is at the lowest in the MKNP probably due to the limited lowland forest of this protected area. Much of the forests in the MKNP are located in much higher elevations.
The population of the Visayan tarictic hornbill might further increase once field surveys shall be made in Panay. Paguntalan claimed the species likely occurs in the three protected areas in Panay – the Northwest Panay Peninsula Protected Landscape, Sibalom Natural Park, and Bulabog-Putian Natural Park. She added that it could be that the Central Panay Mountain is the stronghold of the Visayan tarictic hornbill because it has the largest forest in Panay, but it has no official protection mechanism.
For the last five years, the PhilBio has lead the annual synchronized hornbill count and biodiversity monitoring in the NNNP, MKNP, and BTLNP. That was undertaken in partnership with the DENR, Provincial Environment Management Office of Negros Occidental, and local governments and people’s organizations surrounding the three protected areas. Several teams have been organized and a total of 232 sampling points were surveyed for 635 times. Using the Distance program, the population density was arrived to come out with an estimate of individual hornbills in three protected areas, Paguntalan further said.*