Data Zone
Taxonomic note
Rhabdotorrhinus leucocephalus (del Hoyo and Collar 2014) was previously placed in the genus Aceros.
Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.
| Critically Endangered | Endangered | Vulnerable |
|---|---|---|
| - | - | - |
| Year | Category | Criteria |
|---|---|---|
| 2020 | Near Threatened | C1 |
| 2016 | Near Threatened | A2c+3c+4c;C1 |
| 2012 | Near Threatened | A2c+3c+4c;C1 |
| 2008 | Near Threatened | A2c; A3c; A4c; C1 |
| 2004 | Near Threatened | |
| 2000 | Lower Risk/Near Threatened | |
| 1996 | Endangered | |
| 1994 | Endangered | |
| 1988 | Lower Risk/Least Concern |
| Migratory status | not a migrant | Forest dependency | high |
| Land-mass type |
shelf island |
Average mass | - |
| Estimate | Data quality | |
|---|---|---|
| Extent of Occurrence (breeding/resident) | 168,000 km2 | medium |
| Severely fragmented? | no | - |
| Estimate | Data quality | Derivation | Year of estimate | |
|---|---|---|---|---|
| Population size | unknown | - | - | - |
| Population trend | decreasing | poor | suspected | 2001-2024 |
| Rate of change over the past 10 years/3 generations (longer of the two periods) | 8-15% | - | - | - |
| Rate of change over the future 10 years/3 generations (longer of the two periods) | 15-25% | - | - | - |
| Rate of change over the past & future 10 years/3 generations (longer of the two periods) | 15-25% | - | - | - |
| Generation length | 7.76 years | - | - | - |
Population justification: The population size of this species has not been quantified, but it has been described as rare in general. The species is also dependent on primary forest, which is undergoing moderately rapid forest loss within its small range. Hence, while the population has not been directly quantified, it is likely to be < 10,000 mature individuals.
Trend justification: Data on direct trends are lacking, but a moderately rapid population decline is likely to be taking place as a result of habitat loss, as well as pressure from hunting and trapping. Between 2001 and 2019, forest cover at >30% was lost at a rate of 8.1% (Global Forest Watch, 2020). This equates to a decline rate of 10% over three generations. Between 2016 and 2019, forest cover of >30% was lost at a rate of 2.7% (Global Forest Watch 2020). Projecting this rate of loss over three generations equates to a suspected future decline rate of 19% over three generations based on forest loss alone. In addition to forest loss, the species is also subject to pressure from hunting and trapping, hence the overall rate of decline is suspected to fall in the 15-25% band.
| Country/Territory | Presence | Origin | Resident | Breeding visitor | Non-breeding visitor | Passage migrant |
|---|---|---|---|---|---|---|
| Philippines | extant | native | yes |
| Country/Territory | IBA Name |
|---|---|
| Philippines | Bislig |
| Philippines | Camiguin island |
| Philippines | Lake Lanao |
| Philippines | Mount Agtuuganon and Mount Pasian |
| Philippines | Mount Apo |
| Philippines | Mount Balatukan |
| Philippines | Mount Busa-Kiamba |
| Philippines | Mount Daguma |
| Philippines | Mount Diwata Range |
| Philippines | Mount Hamiguitan (Tumadgo peak) |
| Philippines | Mount Hilong-hilong |
| Philippines | Mount Kaluayan - Mount Kinabalian Complex |
| Philippines | Mount Kambinlio and Mount Redondo |
| Philippines | Mount Kitanglad |
| Philippines | Mount Latian complex |
| Philippines | Mount Malindang |
| Philippines | Mount Matutum |
| Philippines | Mount Piagayungan |
| Philippines | Mount Sinaka |
| Philippines | Mount Sugarloaf |
| Philippines | Mount Timolan |
| Philippines | Pasonanca watershed |
| Habitat (level 1) | Habitat (level 2) | Importance | Occurrence |
|---|---|---|---|
| Forest | Subtropical/Tropical Moist Lowland | major | resident |
| Altitude | 300 - 1000 m | Occasional altitudinal limits |
| Threat (level 1) | Threat (level 2) | Impact and Stresses | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Agriculture & aquaculture | Annual & perennial non-timber crops - Small-holder farming | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
|
|||||||||
| Agriculture & aquaculture | Wood & pulp plantations - Small-holder plantations | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Slow, Significant Declines | Medium Impact: 6 | ||||||
|
|||||||||
| Biological resource use | Hunting & trapping terrestrial animals - Intentional use (species is the target) | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Slow, Significant Declines | Low Impact: 5 | ||||||
|
|||||||||
| Biological resource use | Logging & wood harvesting - Unintentional effects: (large scale) [harvest] | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Slow, Significant Declines | Low Impact: 5 | ||||||
|
|||||||||
| Purpose | Scale |
|---|---|
| Food - human | subsistence, national |
| Pets/display animals, horticulture | subsistence, national |
Recommended citation
BirdLife International (2024) Species factsheet: Writhed Hornbill Rhabdotorrhinus leucocephalus. Downloaded from
https://datazone.birdlife.org/species/factsheet/writhed-hornbill-rhabdotorrhinus-leucocephalus 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.