VU
Palawan Hornbill Anthracoceros marchei



Justification

Justification of Red List Category
This hornbill has a small population which is declining rapidly as a result of the loss of lowland forest, compounded by hunting and capture for the captive bird trade, and it therefore qualifies as Vulnerable.

Population justification
The population is estimated to number 2,500-9,999 mature individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied.

Trend justification
The species is suspected to be declining rapidly, owing to the extensive and on-going clearance of remaining lowland forest within its range, combined with the impact of hunting.

Distribution and population

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).

Ecology

It inhabits all storeys of forests, including secondary 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).

Threats

Deforestation in lowland Palawan and on many of its satellite islands (e.g. Culion, Balabac and Busuanga) has been extensive. . The lowland forests which are core habitat for the species are the least protected forest ecosystems in Palawan (Widmann et al. 2015). 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).

Conservation actions

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).

Conservation Actions Proposed
Conduct surveys in remaining lowland forests, particularly around Mts Victoria and Mantalingahan, to identify and propose for protection additional key sites. Continue research into the year-round ecological requirements to inform existing nest protection schemes and habitat restoration. Assess the extent of illegal international trade.  Support the proposed extension of St Paul's Subterranean River National Park. Formally protect forests at Iwahig. Allocate greater resources towards more effective control of hunting in Palawan forests and initiate conservation awareness campaigns amongst forest product collectors.

Identification

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.

Acknowledgements

Text account compilers
Bird, J., Butchart, S., Davidson, P., Derhé, M., Lowen, J., Peet, N., Martin, R

Contributors
Tabaranza, B., Widmann, P.


Recommended citation
BirdLife International (2021) Species factsheet: Anthracoceros marchei. Downloaded from http://www.birdlife.org on 20/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/10/2021.