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

Taxonomic note

Ixos nicobariensis (del Hoyo and Collar 2016) was previously listed as Hypsipetes nicobariensis.

 

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2023	Near Threatened	B1b(ii,iii)+2b(ii,iii)
2016	Near Threatened	C1
2012	Near Threatened	C1
2009	Near Threatened	C1
2008	Vulnerable
2004	Vulnerable
2000	Vulnerable
1996	Vulnerable
1994	Vulnerable
1988	Near Threatened

Migratory status	not a migrant	Forest dependency	medium
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	3,100 km2	medium
Area of Occupancy (breeding/resident)	880 km2
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	3500-20000 mature individuals	poor	inferred	2022
Population trend	decreasing	poor	suspected	2014-2026
Rate of change over the past 10 years/3 generations (longer of the two periods)	1-9%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	1-9%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	1-9%	-	-	-
Generation length	3.9 years	-	-	-
Number of subpopulations	7	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: The population size of this species has not previously been estimated, although it is among the most common forest species on the islands it occupies (Zaibin 2017, Goyal 2020). In total, approximately 330 km² of forest lies within its range (per Global Forest Watch 2022); although no population density exists for this species, congenerics and other forest bulbuls in South-East Asia typically occur at densities of 20-100 birds/km² (see Santini et al. 2018 data). Occupancy within the species range is likely to be high (postulated here to be 80-95%), thus the population size is likely to be c.5,300-31,400 birds, or c.3,500-20,000 mature individuals. The island of Katchall has the most forest (c.134 km²) and, using these same assumptions, is likely to host 1,400-8,000 mature individuals.

Trend justification: A total of 250 km² of forest was lost on the Nicobar Islands between 1976 and 2014 (Reddy et al. 2016), although rates of forest loss since have been slower. In the three generations (11.7 years; Bird et al. 2020) to 2021, forest cover loss in this species' range was reduced by 3-4% (per Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein). As a forest dependent species (see Goyal 2020), the rate of population reduction is thought to be similar and is placed here in an ongoing bracket of 1-9% over three generations.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
India	extant	native	yes

Country/Territory	IBA Name
India	Tillangchong, Camorta, Katchal, Nancowry and Trinkat

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Plantations	suitable	resident
Artificial/Terrestrial	Rural Gardens	suitable	resident
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	0 - 600 m	Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Scale Unknown/Unrecorded	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Intentional use (species is the target)	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Negligible declines		Low Impact: 4
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Pycnonotus jocosus	Timing		Scope		Severity		Impact
		Ongoing		Whole (>90%)		Unknown		Unknown
		Stresses Competition
Residential & commercial development	Commercial & industrial areas	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		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
Transportation & service corridors	Roads & railroads	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation

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Recommended citation
BirdLife International (2024) Species factsheet: Nicobar Bulbul Ixos nicobariensis. Downloaded from https://datazone.birdlife.org/species/factsheet/nicobar-bulbul-ixos-nicobariensis on 23/11/2024.
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 23/11/2024.