Data Zone
Justification of Red List category
This hornbill is projected to decline rapidly as a result of the loss of lowland forest, compounded by hunting and capture for the captive bird trade. It therefore qualifies as Vulnerable.
Population justification
A 2006 survey in Puerto Princesa Subterranean River National Park, the species was recorded at densities of 19.6 individuals/km2 in old growth forest; 13.8 in advanced growth secondary forest; and 9.6 individuals/km2 in early secondary growth; it was absent from cultivated areas (Mallari et al. 2011). The species has also been recorded in tree-dominated agricultural areas (Widmann et al. 2015). Using the densities they estimated and land cover data from 2000, Mallari et al. (2011) predicted there could be a maximum of 59,000 individuals in old growth forest alone. Their data allow for further extrapolations of 58,000-84,000 additional birds in second growth, equivalent to a total population of 77,000-94,000 mature individuals. However, Puerto Princesa Subterranean River National Park is protected and rates of hunting are likely to be lower here, and these extrapolations assume complete and even occupancy. Accounting for habitat loss since 2000, habitat fragmentation effects, likely hunting pressures outside the National Park, uneven occupancy rates and this species's reliance on hollows for nesting, a more precautionary population size of 20,000-50,000 mature individuals is suspected.
Trend justification
Between 2016 and 2020, forest loss in this species's range has averaged c.1.4% per annum, projected to c.31% over the next three generations (Global Forest Watch 2021). Although this species can tolerate forest degradation (Malleri et al. 2011), it is absent entirely from cultivation which continues to expand on Palawan. The impact of hunting is unquantified but is assumed to be high outside protected areas since this is the only hornbill on the island. The impact of these threats is predicted to accelerate with Palawan's increasing human population (PSA 2015) and the rate of population reduction is therefore projected to be 30-49% over the current and future three-generation periods.
Anthracoceros marchei is endemic to Palawan and its satellite islands in the Philippines. It has recently been described as quite common to uncommon and has evidently declined. There have been recent observations from c.10 localities, including several tiny offshore islands whose small populations appear relatively secure. It appears to be fairly common in Puerto Princessa Subterranean River National Park and the El Nido Reserve; Iwahig Prison and Penal Farm, Omoi Cockatoo Reserve, Dumaran Island, Pandanan Island and Culasian Managed Resource Protected Area, Rizal, southern Palawan may also be key sites for the species (P. Widmann in litt. 2007, 2016). In a 2006 survey in Puerto Princesa Subterranean River National Park, the species was recorded at densities of 19.6 ± 3.6 individuals/km2 in old growth forest; 13.8 ± 4.8 individuals/km2 in advanced growth secondary forest forest; and 9.6 ± 7.6 individuals/km2 in old growth forest (Mallari et al. 2011). The species has also been recorded in tree-dominated agricultural areas (Widmann et al. 2015).
It inhabits all storeys of forests, including second growth, up to 900 m, but probably requires large trees for nesting. It also frequents mangroves, cultivated land and bushlands, all close to contiguous forest, although a 2006 survey did not record the species in cultivation at all, despite 4 months of fieldwork in the Puerto Princessa Subterranean River National Park in Palawan (Mallari et al. 2011). In this area, the species was recorded to reach its highest densities in old growth forest, followed by advanced growth secondary forest, and lowest densities in early growth secondary forest (Mallari et al. 2011). It may make local movements in response to food availability. The species nests in canopy-forming or emergent trees; breeding season lasts from end of March to end of July. Clutch sizes range from mostly two, but up to four eggs, and survival rate from nestling to fledgling stages was 82% in 12 monitored breeding attempts (Widmann et al. 2015).
Deforestation in lowland Palawan and on many of its satellite islands (e.g. Culion, Balabac and Busuanga) has been extensive and is ongoing. The lowland forests which are core habitat for the species are the least protected forest ecosystems in Palawan (Widmann et al. 2015). Between 2000 and 2020, annual forest loss equalled c.0.8% , accelerating to 1.38% in 2016-2020 (Global Forest Watch 2020). Logging and mining concessions have been granted for much of the island's remaining forest. Illegal logging is thought to persist in the south, and forest at Iwahig Prison and Penal Farm may be threatened by illegal encroachment (P. Widmann in litt. 2016). Hunting for food and sport is also a threat: interviews conducted in south Palawan indicate that the species is regularly hunted for bushmeat (Villafuerte-van den Beukel et al. 2009). Nest trees may be raided for young birds with the species apparently becoming increasingly common in the pet trade, nationally and to a certain degree also internationally (Widmann et al. 2015). With an increasing population on the island (1.8% increase per year 2000-2015 [PSA 2015]) these threats are unlikely to abate in the near future.
Conservation Actions Underway
CITES Appendix II. The whole of Palawan is classed as a game reserve, where hunting is illegal, and the island was designated as a Biosphere Reserve in 1990, although the legislation controlling habitat alteration and hunting is difficult to enforce effectively. It occurs in the protected areas of El Nido Marine Reserve, Puerto Princessa Subterranean River National Park and the newly created Omoi Cockatoo Reserve, Dumaran Island and Culasian Managed Resource Protected Area, Rizal, southern Palawan. In the latter two sites and on Pandanan Island the species benefits from a warden scheme originally created for the Philippine Cockatoo Cacatua haematuropygia (Kinnaird and O'Brien 2007, Widmann et al. 2015). Hornbill nests are monitored and basic information biology are collected; the species is integrated in the PRIDE campaigns of Katala Foundation (P. Widmann in litt. 2016). The Puerto Princesa Subterranean River National Park is planned to be expanded to include the remaining forest of Cleopatra's Needle where the species is known to occur (B. Tabaranza in litt. 2007). The park is actively managed by the City Government of Puerto Princesa. It featured on a bilingual environmental awareness poster in the "Only in the Philippines" series. Wildlife trade is addressed through Katala Foundations "Southern Palawan Anti-Poaching Initiative", and a more recent cooperation of Katala Foundation with the Palawan Council for Sustainable Development, particularly covering the lowland forest areas of Iwahig Prison and Penal Farm (P. Widmann in litt. 2007, 2016). Identified food plants and nest trees of the species are propagated for habitat restoration on Dumaran Island (P. Widmann in litt. 2016).
70 cm. Smallish, forest-dwelling hornbill. White tail. Rest of plumage entirely black, glossed dark greenish on upperparts. Large, creamy-white to yellowish bill and casque with dark base to lower mandible. Whitish-tinged blue bare orbital and gular skin. Female and immatures have reduced casque. Voice Various loud, raucous calls including kaaww and kreik-kreik. Hints Most easily found at forest edge.
Text account compilers
Berryman, A.
Contributors
Tabaranza, B., Widmann, P., Lowen, J., Derhé, M., Butchart, S., Martin, R., Bird, J., Davidson, P. & Peet, N.
Recommended citation
BirdLife International (2024) Species factsheet: Palawan Hornbill Anthracoceros marchei. Downloaded from
https://datazone.birdlife.org/species/factsheet/palawan-hornbill-anthracoceros-marchei on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 22/11/2024.