The rufous hornbill (Buceros hydrocorax), also known as the Philippine hornbill and locally as kalaw (pronounced KAH-lau), is a large species of hornbill endemic to the Philippines (the largest hornbill in the country). The are referred by locals as the "clock-of-the-mountains" due to its large booming call which typically occur of every hour. It occurs in moist tropical lowland forest. They are now considered to be a threatened species and its reasons for decline being habitat destruction, hunting and poaching for the illegal pet trade. It is illegal to hunt, capture or possess rufous hornbills under Philippine Law RA 9147. Distribution and Taxonomy It is endemic to the Philippines, where it occurs in primary, mature secondary and disturbed forests on 11 islands: The bill of the nominate subspecies is entirely red, while the bill of the subspecies semigaleatus and mindanensis are pale yellow on the distal half. Subspecies Three subspecies are recognized" Buceros hydrocorax hydrocorax: Luzon and Marinduque, Larger with an all red bill, large casque Now extinct on Marinduque Buceros hydrocorax semigaelatus:Samar, Leyte, Bohol, Panaon, Biliran, Calicoan and Buad ; Yellow front half of beak; flatter top of head with the casque (horn) smaller and merges into the maxilla Buceros hydrocorax mindanensis: Dinagat, Siargao, Mindanao (plus Balut, Bucas and Talicud) and Basilan; Yellow front half of beak; large casque The HBW and BirdLife International Illustrated Checklist of the Birds of the World has split this into two species with the Northern Rufous Hornbill consisting of the nominate and the Southern Rufous Hornbill consisting of the semigaelatus and mindanensis subspecies. Behaviour It is sometimes called "the clock of the mountains" because of its periodic noontime call. It has been recorded to have been preyed upon by the Philippine eagle. Breeding As with other hornbills, females seal themselves within the nest cavity, where they lay the clutch, and remain with the growing young for most or all of the nesting period. In some species, the male helps with the sealing process from outside the nest cavity. The nestlings and the female are fed by the male through a narrow vertical slit in the sealed nest opening, at times joined by non-breeding helper males. Nesting time will last in average of 4–6 months. In this duration the male will provide food to his confine female and nestling. They maintain the year- pair bonds and will paired together until many years’ time and