Rufous-necked Hornbill Aceros nipalensis


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
- - A2cd+3cd+4cd

Red List history
Year Category Criteria
2020 Vulnerable A2cd+3cd+4cd
2018 Vulnerable A2cd+3cd+4cd
2016 Vulnerable A2cd+3cd+4cd
2012 Vulnerable A2cd+3cd+4cd
2008 Vulnerable A2c,d; A3c,d; A4c,d
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened
Species attributes

Migratory status not a migrant Forest dependency High
Land mass type Land-mass type - continent
Average mass 2385 g

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 1,580,000 medium
Number of locations -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 7000-10000 medium estimated 2016
Population trend Decreasing poor inferred -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 30-49 - - -
Decline (10 years/3 generation past and future) 30-49 - - -
Number of subpopulations 2-100 - - -
Percentage in largest subpopulation - - -
Generation length (yrs) 9.4 - - -

Population justification: Density estimates in Thailand from 3 different sites have varied between 3.69 birds/km2 (Jornburom et al. 2010) in Huai Kha Khaeng Wildlife Sanctuary to 5.5 birds/km2 in Thung Yai Naresuan Wildlife Sacutaty (Jinamoy et al. 2013) and 8.06 birds/km2 in Thung Yai Naresuan West. Density estimates in Arunachal Pradesh, north-east India were 6.9 birds/km2 in Namdapha Tiger Reserve (Naniwadekar and Datta 2013) and 6.12 birds/km2 in Eaglenest Wildlife Sanctuary (Shukla et al. 2016). Based on these population estimates, coupled with an the extent of suitable habitat remaining within the occupied range of the species estimates that the global population is 12,000-15,000 individuals (R. Naniwadekar, A. Datta and P. Lo in litt. 2016). This is equivalent to 7,900-9,900 mature individuals, rounded here to 7,000-10,000 mature individuals.

Trend justification: Across much of its range, forest has been cleared at a rapid rate. In combination with intense hunting pressure (see Datta 2009, Naniwadekar et al. 2015a, Naniwadekar et al. 2016), these processes are inferred to be driving rapid population declines, placed here in the band of 30-49% decline over three generations (28.2 years; Bird et al. 2020).

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

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Vietnam Che Tao
Vietnam Pu Mat
Bhutan Toorsa Strict Nature Reserve
Bhutan Phipsoo Wildlife Sanctuary
Bhutan Jigme Singye Wangchuk National Park
Bhutan Royal Manas National Park
Bhutan Thrumsing La National Park
Bhutan Khaling / Neoli Wildlife Sanctuary
Bhutan Deothang / Narphang / Samdrup Jongkhar
Bhutan Kamji
Bhutan Kori La
Bhutan Samtse
Bhutan Sarpang-Gelephu foothills
China (mainland) Mêdog
China (mainland) Lhakhang
China (mainland) Tongbiguan
China (mainland) Xishuangbanna
Myanmar Hukaung Valley
Myanmar Hponkanrazi
Myanmar Hkakaborazi
Myanmar Ngwe Taung
Myanmar Nat-yekan
Myanmar Kyauk Pan Taung
Thailand Mae Wong
Thailand Umphang
Thailand Thung Yai - Naresuan
Thailand Huai Kha Khaeng
Laos Phou Dendin
Laos Nam Xam
Laos Phou Loeuy
Laos Upper Xe Bangfai
Laos Hin Namno
Laos Eastern Bolikhamxay Mountains
Laos Nakai-Nam Theun
India Chaglagaum - Denning - Walong
India Chayang Tajo - Khenewa - Lada
India Dichu Reserve Forest
India Eaglenest and Sessa Sanctuaries
India Itanagar Wildlife Sanctuary
India Kane Wildlife Sanctuary
India Koloriang - Sarli - Damin area
India Magu Thingbu
India Manabum and Tengapani Reserve Forests
India Mechuka - Monigong - Jorgging
India Mehao Wildlife Sanctuary
India Mouling National Park
India Nacho - Limeking - Taksing - Majha
India Nafra - Lada area
India Namdapha - Kamlang
India Namsangmukh - Borduria
India Pakhui or Pakke Wildlife Sanctuary
India Papum Reserve Forest
India Shergaon, Mandla - Phudung and Kalaktang
India Taley Valley Wildlife Sanctuary
India The Chapories of Lohit Reserve
India Yardi - Rabe Supse Wildlife Sanctuary
India Behali Reserve Forest
India Dhansiri Reserve Forest
India East and North Karbi Anglong Wildlife Sanctuaries
India Jatinga
India Langting-Mupa Reserve Forest
India Manas National Park
India Nameri National Park
India Ripu and Chirang Reserve Forests
India Sonai-Rupai Wildlife Sanctuary
India Subansiri
India Upper Dihing (East) Complex
India Upper Dihing (West) Complex
India Nongkhyllem and adjacent areas
India Norpuh Reserve Forests
India Saipung
India Ango or Anko Hills
India Bunning Wildlife Sanctuary
India Jiri - Makru Wildlife Sanctuary
India Kailam Wildlife Sanctuary
India Shiroi Community Forest
India Fakim Wildlife Sanctuary and Saramati area
India Intaki National Park
India Mount Paona
India Mount Zanibu
India Mount Ziphu
India Satoi Range
India Fambong Lho Wildlife Sanctuary - Himalayan Zoological Park - Ratey Chu Reserve Forest
India Lowland forests of South Sikkim (Melli-Baguwa-Kitam, Jorethang-Namchi, Sombarey)
India Maenam Wildlife Sanctuary - Tendong Reserve Forest
India Pangolakha Wildlife Sanctuary - Zuluk - Bedang Tso - Natula Complex
India Buxa Tiger Reserve (National Park)
India Lava - Neora Valley National Park
India Mahananda Wildlife Sanctuary
China (mainland) Nabanhe Nature Reserve
China (mainland) Yarlung Zangbo Daxiagu Nature Reserve
China (mainland) Dehong Zizhizhou
Myanmar Pachan
China (mainland) Gaoligong Shan Nature Reserve (southern section)
Myanmar Babulon Htan
Myanmar May Hka Area
India Namtok, Namheik, Nampong and Manmao
India Sirkum Pahar
India Barail Range
India Chirang Reserve Forest
India Ripu Reserve Forest
India Sessa Orchid Sanctuary
India Monigong - Jorgging - Tuting
India Mandla Phudung
India Kamlang Wildlife Sanctuary and Reserve Forest
India Shergaon - Tenzinggang - Kalaktang
India Namdapha National Park
India Mechuka - Tato
India Dailong Rongku Forest
India Eaglenest Wildlife Sanctuary
India Chaglagaum - Denning
India Barail Range forests
India Walong
India Thorangtlang Wildlife Sanctuary

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Forest Subtropical/Tropical Moist Lowland major resident
Forest Subtropical/Tropical Moist Montane major resident
Altitude 300 - 2400 m Occasional altitudinal limits 150 - 2900 m

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Shifting agriculture Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Species disturbance, 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%) Rapid Declines Medium Impact: 7
Species mortality
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Rapid Declines Medium Impact: 6
Ecosystem degradation
Residential & commercial development Commercial & industrial areas Timing Scope Severity Impact
Future Minority (<50%) Unknown Unknown
Ecosystem degradation, Ecosystem conversion
Residential & commercial development Housing & urban areas Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation, Ecosystem conversion

Purpose Primary form used Life stage used Source Scale Level Timing
Food - human - - Non-trivial Recent
Other household goods - - Non-trivial Recent
Pets/display animals, horticulture - - Non-trivial Recent

Recommended citation
BirdLife International (2023) Species factsheet: Aceros nipalensis. Downloaded from on 26/03/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 26/03/2023.