VU
Great Hornbill Buceros bicornis



Taxonomy

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.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - A3cd+4cd

Red List history
Year Category Criteria
2020 Vulnerable A3cd+4cd
2018 Vulnerable A3cd+4cd
2016 Near Threatened A2cd+3cd+4cd; C1
2013 Near Threatened A2cd+3cd+4cd; C1
2012 Near Threatened A2cd+3cd+4cd;C1
2008 Near Threatened A2c,d; A3c,d; A4c,d; C1
2004 Near Threatened
2000 Lower Risk/Near Threatened
1994 Lower Risk/Least Concern
1988 Lower Risk/Least Concern
Species attributes

Migratory status not a migrant Forest dependency High
Land mass type Land-mass type - continent
Land-mass type - shelf island
Average mass -
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 10,300,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 13000-27000 poor inferred 0
Population trend Decreasing medium suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 30-39 - - -
Decline (10 years/3 generation past and future) 30-39 - - -
Number of subpopulations - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 18.3 - - -

Population justification: The population density of the Great Hornbill has been estimated from across several sites in its range. In Arunachal Pradesh in north-east India, the density of Great Hornbill in Namdapha Tiger Reserve was estimated to be around 4 birds per km2 (Naniwadekar and Datta, 2013) in the non-breeding season and this was similar in Pakke Tiger Reserve at 3.8 birds per km2 (Datta et al. unpublished data 2014). In Pakke Tiger Reserve, its overall density was estimated to be around 12 birds per km2 in an earlier study (Dasgupta and Hilaluddin, 2012). The density was estimated to be 1 bird per km2 in forests outside Namdapha Tiger Reserve (Naniwadekar et al. 2015a). In the rainforest fragments, the densities  ranged from 3.4 to 10 birds per km2 (Raman & Mudappa, 2003). The density of Great Hornbill ranged between 1.5-4.4 individuals/km2 in Anamalai and Parambikulam Tiger Reserves, 0-4 individuals per km2 in Reserved Forests of Vazhachal-Sholayar and Malayattur and 0.6-4.5 individuals per km2 in rainforest fragments in Anamalai Hills (Mudappa & Raman, 2009). Densities are higher in Anamalai Tiger Reserve (~4 birds/ km2) as opposed to the adjoining shade coffee plantations (~2 birds/ km2) based on line-transect surveys between January 2017 and April 2018 (Pawar et al. unpublished data).
In Thailand, its population density has been estimated to range between 1.3-4.7 birds per km2 in Huai Kha Khaeng Wildlife Sanctuary, Thung Yai Naresuan Wildlife Sanctuary, Khao Yai National Park, and Budo Sangai Padi National Park. It ranges between 0.04-1.1 birds per km2 in nine other forest complexes in Thailand (Gale and Thongaree 2006, Jornburom et al. 2010, Poonswad et al. 2013). 

These population densities indicate that the population within these sites, given the approximate habitat that lies within a suitable elevation range, can be estimated on a precautionary basis at 23,000 - 71,000 individuals. This is placed in the band 20 - 49,999 individuals, roughly equating to 13,000 - 27,000 mature individuals. Outside protected areas, even if adjacent, population densities can be considerably lower, often well below 1 individual per km2 (Gale and Thongaree 2006, Mudappa and Raman 2009, Naniwadekar et al. 2015), and it has been driven to local extinction across several sites both inside and outside Protected Areas in Arunachal Pradesh (Datta 2002, Naniwadekar et al. 2015a).

Trend justification: An analysis of deforestation between 2000 and 2012 estimated forest loss within the species's range at 26.1% over three generation lengths (55.2 years) (Tracewski et al. 2016). The species is generally intolerant of forest disturbance and additionally severely threatened by hunting. Thus, its actual rate of population decline is likely greater than the estimate decline based on forest loss alone. The rate of decline is tentatively placed in the band 30-49% over three generations. Since this species has a long generation length, with three generations stretching over 55 years, there is insufficient evidence to calculate the magnitude of reduction over the past three generations. Assuming the recent rate of decline remains constant, the species is projected to decline by 30-49% over the next three generations.


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
Bangladesh N Extant Yes
Bhutan N Extant Yes
Cambodia N Extant Yes
China (mainland) N Extant Yes
India N Extant Yes
Indonesia N Extant Yes
Laos N Extant Yes
Malaysia N Extant Yes
Myanmar N Extant Yes
Nepal N Extant Yes
Thailand N Extant Yes
Vietnam N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Vietnam Ke Go
Vietnam Kon Ka Kinh
Vietnam Phong Dien
Vietnam Vu Quang
Vietnam Chu Prong
Vietnam Kon Cha Rang
Vietnam Chu Yang Sin
Vietnam Phong Nha
Vietnam Ke Bang
Vietnam Pu Mat
Vietnam Yok Don
Vietnam Kon Plong
Vietnam Cat Loc
Vietnam Nam Cat Tien
Laos Nam Et
Laos Phou Dendin
Laos Dong Ampham
Laos Hin Namno
Laos Nam Xam
Cambodia Phnom Samkos
Laos Xe Khampho / Xe Pian
Laos Phou Loeuy
Cambodia O Skach
Cambodia Central Cardamoms
Cambodia Phnom Aural
Laos Dong Khanthung
Cambodia Chhep
Laos Upper Xe Kaman
Cambodia Virachey
Cambodia Upper Srepok Catchment
Cambodia Snoul / Keo Sema / O Reang
Laos Eastern Bolikhamxay Mountains
Cambodia Phnom Bokor
Laos Nakai-Nam Theun
Thailand Namtok Huai Yang
India Malayattur Reserve Forest
India Achankovil Forest Division
Nepal Barandabhar forests and wetlands
Nepal Bardia National Park
Nepal Chitwan National Park
Nepal Mai Valley forests
Nepal Parsa Wildlife Reserve
India Jhilmil Jheel Conservation Reserve
India Thorangtlang Wildlife Sanctuary
India Eaglenest Wildlife Sanctuary
India Pilibhit Tiger Reserve
India Camel’s Hump Mountains
India Amangarh Reserve Forest
India Innerline (East) and Barak Reserve Forests
India Pawalgarh Conservation Reserve
India Nandhour Wildlife Sanctuary
India Amboli-Tilari Reserve Forest
India Manas Reserve Forest
India Innerline (West) and Katakhal Reserve Forests
India Krungming Reserve Forest, Khorongma & Kopili-Umrangsu Reservoirs
India Megamalai Mountains
India Sessa Orchid Sanctuary
India Muthikulam-Siruvani Reserve Forest
India Marat Longri Wildlife Sanctuary
India Lumding Reserve Forest
Vietnam Ea So
Vietnam Khe Net
Vietnam Truong Son
Vietnam Lo Go - Xa Mat

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Plantations major resident
Artificial/Terrestrial Rural Gardens major resident
Forest Subtropical/Tropical Moist Lowland major resident
Forest Subtropical/Tropical Moist Montane major resident
Altitude 0 - 2000 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Agro-industry farming Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Wood & pulp plantations - Agro-industry plantations Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species mortality
Biological resource use Hunting & trapping terrestrial animals - Unintentional effects (species is not the target) Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species mortality
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Ecosystem degradation, Ecosystem conversion
Residential & commercial development Housing & urban areas Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Ecosystem degradation, Ecosystem conversion

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Food - human - - Non-trivial Recent
Medicine - human & veterinary - - Non-trivial Recent
Pets/display animals, horticulture - - International Non-trivial Recent

Recommended citation
BirdLife International (2021) Species factsheet: Buceros bicornis. Downloaded from http://www.birdlife.org on 09/05/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 09/05/2021.