Walden's hornbill (Rhabdotorrhinus waldeni) locally called dulungan, also known as the Visayan wrinkled hornbill, rufous-headed hornbill or writhed-billed hornbill, is a critically endangered species of hornbill living in the rainforests on the islands of Negros and Panay in the Philippines. It is closely related to the writhed hornbill, but can be recognized by the yellow throat and ocular skin in the male, and the blue throat and ocular skin in the female (both throat and ocular skin are deep orange or red in both sexes of the writhed hornbill). Its binomial name commemorates the Scottish ornithologist Viscount Walden. It is considered one of the Western Visayas Big 5 which includes the Negros bleeding-heart pigeon, Visayan spotted deer, Visayan hornbill and the Visayan warty pig. Description EBird describes the bird as "A large rare bird of lowland and foothill forest on Panay and Negros, although almost extinct on the latter. Mostly black with a cream-colored tail with black terminal band, an orange casque , and a wrinkled lower bill. Male has a rufous head, a yellow pouch, and yellow around the eye. Female has a black neck and head, a smaller bill and casque , and blue and yellow around the eye and on the chin. The only other hornbill in range is the Visayan hornbill but Writhe-billed is larger, with a pale bill. Voice includes a three-noted throaty chuckle.." They exhibit sexual dimorphism with the males having a rufous head and yellow facial skin while the females having a black head and blue facial skin and a smaller bill. Habitat and behaviour It inhabits closed-canopy forests, also frequenting logged areas and occasionally isolated trees in clearings at an altitudinal range of 400 to 1,200 m Panay and 350 to 950 m in Negros. It prefers areas abundant fruit-bearing trees for feeding and large trees for nesting. They are known to live in small and noisy flocks. The Walden's hornbills are cavity nesters and use natural or carved-out hollows in tree trunks for its nest. As other hornbills, they reproduce very slowly. As lack of appropriate nesting sites is a problem, nest boxes are being attached to tree trunks in certain reserves. It is omnivorous, taking some animal matter to its nests and feeding in the canopy on figs and other fruits. It may make local nomadic movements in response to food availability. It nests in large trees. Conservation status This