• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

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.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
C2a(i,ii); D	A2cd+3cd+4cd; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i,ii); D	A2cd+3cd+4cd; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v); C2a(i,ii); D1+2

Red List history

Year	Category	Criteria
2020	Critically Endangered	C2a(i,ii); D
2016	Critically Endangered	C2a(i,ii); D
2013	Critically Endangered	C2a(i,ii);D
2012	Critically Endangered	C2a(i,ii);D
2010	Critically Endangered	C2a(ii); D1
2009	Critically Endangered	C2a(ii); D1
2008	Critically Endangered
2006	Critically Endangered
2004	Critically Endangered
2000	Critically Endangered
1996	Critically Endangered
1994	Critically Endangered
1988	Threatened

Migratory status	not a migrant	Forest dependency	high
Land-mass type	Land-mass type - shelf island	Average mass	-

	Estimate	Data quality
Extent of Occurrence breeding/resident (km2)	780	medium
Area of Occupancy breeding/resident (km2)	400
Number of locations	2-5	-
Severely fragmented?	yes	-

	Value	Data quality	Derivation	Year of estimate
Number of mature individuals	1-49	medium	suspected	1999
Population trend	decreasing	poor	inferred	2007-2024
Decline % (10 years/3 generations future)	50-79	-	-	-
Decline % (10 years/3 generations past and future)	50-79	-	-	-
Number of subpopulations	1	-	-	-
Percentage in largest subpopulation	100	-	-	-
Generation length (years)	5.8	-	-	-

Population justification: The species perhaps numbers fewer than 20 pairs in the main mountain range of Tawi-Tawi. Therefore, the population size is considered to be extremely small, and is placed here in the range 1-49 mature individuals.

Trend justification: Described as common to abundant in the late 19th century, this species is thought to have undergone a very rapid decline over the last ten years, and persists with certainty only on Tawi-Tawi. Here, extremely rapid conversion of habitat to oil palm plantations was predicted to cause near-total forest loss, but to date these predictions have not been vindicated.

Country/Territory	Presence	Origin	Resident	Breeding	Non-breeding	Passage
Philippines	extant	native	yes

Country/Territory	IBA Name
Philippines	Mount Dajo National Park
Philippines	Tawi-tawi Island

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Forest	Subtropical/Tropical Moist Montane	major	resident
Altitude		Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Agro-industry farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Unknown		Unknown
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Livestock farming & ranching - Agro-industry grazing, ranching or farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Unknown		Unknown
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Wood & pulp plantations - Scale Unknown/Unrecorded	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Unknown		Unknown
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Ongoing		Whole (>90%)		Slow, Significant Declines		Medium Impact: 7
		Stresses Reduced reproductive success, Species mortality
Biological resource use	Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Very Rapid Declines		High Impact: 8
		Stresses Ecosystem degradation
Climate change & severe weather	Habitat shifting & alteration	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Unknown		Unknown
		Stresses Indirect ecosystem effects, Ecosystem degradation
Energy production & mining	Mining & quarrying	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Residential & commercial development	Commercial & industrial areas	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Unknown		Unknown
		Stresses Ecosystem degradation, Ecosystem conversion

Purpose	Primary form used	Life stage used	Source	Scale	Level	Timing
Food - human	-	-			non-trivial	recent
Pets/display animals, horticulture	-	-			non-trivial	recent
Sport hunting/specimen collecting	-	-			non-trivial	recent

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Recommended citation
BirdLife International (2023) Species factsheet: Anthracoceros montani. Downloaded from http://datazone.birdlife.org/species/factsheet/sulu-hornbill-anthracoceros-montani on 01/10/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 01/10/2023.