 |
 Writhed-Billed Hornbill Aceros waldeni
Raucous, big, and brassy, hornbills once inhabited all of the larger islands of the Philippines and figure prominently in the folklore of many parts of the country. Each of the five species exhibits geographic variation, with each of the Ice-Age islands having its uniquely colored population. Some taxonomists now argue that each of these is a distinct species. The complexity of this issue underscores the fact that hornbills, like most other Philippine animals, still show the effects of the distant past when sea levels were lower and broad land-bridges connected many of the islands. The bills of these birds are enormous and usually brightly colored. The top of the bill is a hollow structure called a casque that serves as a resonating chamber for the bird's calls. Hornbills eat a wide range of foods (including mice and nestling birds), but depend on wild figs in old-growth lowland rain forest, as do many other birds, mammals, and insects. They forage high in the canopy in small flocks that are almost always family groups, noisily calling to each other as they spot interesting things to eat or potential predators; they are said to take special pleasure in pestering the larger but less maneuverable Philippine eagles. Like most large birds, they reproduce very slowly and live for a long time (perhaps as long as 20 years), and take great care raising their young. When the female is ready to lay eggs, the male brings mud that the pair fashions into a solid wall covering most of the opening into their tree-hole nest. The female stays inside the tree-hole to incubate the eggs and nestlings until the young are ready to fly, entirely dependent on her mate to bring food for herself and their brood. Animals that reproduce as slowly as writhed-billed hornbills (Aceros waldeni) are generally unable to survive heavy hunting pressure, and those that require lowland rain forest are especially vulnerable to drastic population decline when the forest is logged. This double jeopardy has hit the hornbills hard: Each day, the harsh but familiar and distinctive calls of hornbills echo through fewer and fewer valleys in the Philippines. Many local populations are extinct, and many of those remaining are critically endangered. The writhed-billed hornbill and several of the species/subspecies from the Ice Age island of Greater Negros-Panay are virtually extinct, and a distinctive population from Ticao island is believed to be the first hornbill in the world to have become extinct. |
|
 |
Philippine
Rain Forest Home | Introduction
| Discovering Diversity | Origins and Dimensions of Biodiversity
| Vanishing Treasures | Causes and Effects of Deforestation
| Prospects for Recovery | Bibliography and Credits | Field
Museum Home |
 |
| © 2007 The Field Museum, All Rights Reserved 1400 S. Lake Shore Dr, Chicago, IL 60605-2496 312.922.9410 Technical Support |
|