Hornbills are among the most enigmatic forest birds in the old-world tropics. Due to their frugivorous habits, they belong to the most efficient seed dispersers among birds, and therefore play a vital role in the regeneration of tropical forest ecosystems. Hornbills have a unique breeding biology, which sets them apart from all other bird families. During the breeding season the female is sealed into a tree cavity, where she stays during the complete incubating and fledging period of the offspring. Both female and chicks are completely dependent on the male to provide food during this phase.
The Palawan group of islands has its own hornbill species, the aptly named Palawan Hornbill, which only can be found in this region. Still very little is known on the biology of the species. Its habitat, lowland and hill forests are cleared at an alarming rate in Palawan. The species is also persecuted for the illegal pet trade, and also illegally shot by recreational hunters or for food. Due to these threat factors, the Palawan Hornbill is listed as ‘Vulnerable’ by the International Union for the Conservation of Nature. As a large tree cavity breeder, the Palawan Hornbill is dependent on larger trees for its existence. This species is therefore an indicator for good forest conditions (although it can tolerate a degree of habitat degradation in its foraging area). It also makes a very suitable ‘umbrella species’ for other bird species that rely on tree cavities for breeding, of which Palawan has a wide variety. Four woodpecker species can be found on the island group, two of which are globally threatened and two are endemic for the Palawan faunal region. Woodpeckers are keystone species in all type of forests, since they are capable of building cavities, whereas other bird groups depend on the availability of existing one. Several owl, parrot, kingfisher and a roller species are such secondary cavity nesters. As with the Palawan Hornbill, next to nothing is known on the biology and their conservation requirements of the majority of these birds, particularly the endemic ones.
Katala Foundation implements nest monitoring schemes for Palawan Hornbill and other cavity nesting birds in the Dumaran, Iwahig and Pandanan/Bugsuk project sites. This includes research on basic biology of the species, particularly on breeding and foraging. Nest boxes for hornbills are currently designed and field-tested. Patrols in hornbill habitat are conducted to prevent or persecute illegal activities, especially logging and wildlife poaching.