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

Taxonomic note
A comprehensive phylogenetic analysis of bulbuls (Shakya and Sheldon 2017) recommends that Pycnonotus squamatus, P. cyaniventris and P. erythropthalmos are moved into the genus Ixidia Blyth, 1846 ('Ixidea' is an error in Shakya and Sheldon 2017, citing Fishpool and Tobias [2005] who use Ixidia), consequently I. squamata, I. cyaniventris and I. erythropthalmos (Handbook of the Birds of the World and BirdLife International 2019) are accepted.

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.
Fishpool, L.D.C. and Tobias, J.A. 2005. Family Pycnonotidae (Bulbuls). In: J. del Hoyo, A. Elliott and C. Christie (eds), Handbook of Birds of the World, pp. 124-250. Lynx Edicions, Barcelona, Spain.
Handbook of the Birds of the World and BirdLife International. 2019. Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 4. Available at: https://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v4_Dec19.zip.
Shakya, S. B., & Sheldon, F. H. 2017. The phylogeny of the world's bulbuls (Pycnonotidae) inferred using a supermatrix approach. Ibis 159(3): 498-509.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2024	Near Threatened	A2c+3c+4c
2016	Near Threatened	A2c+3c+4c
2012	Near Threatened	A2c+3c+4c
2008	Near Threatened	A2c; A3c; A4c
2004	Near Threatened
2000	Lower Risk/Near Threatened
1994	Lower Risk/Least Concern
1988	Lower Risk/Least Concern

Migratory status	not a migrant	Forest dependency	high
Land-mass type	continent shelf island	Average mass	22 g

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	3,670,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	unknown	-	-	-
Population trend	decreasing	poor	inferred	2016-2026
Rate of change over the past 10 years/3 generations (longer of the two periods)	15-25%	-	-	-
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	3.04 years	-	-	-
Number of subpopulations	3-50	-	-	-
Percentage of mature individuals in largest subpopulation	1-89%	-	-	-

Population justification: The global population size of this species has not been quantified, but it is relatively common (Wells 2007, Eaton et al. 2021, eBird 2024) in remaining tracts of lowland forest, which remain widespread, although much reduced in extent compared to three generations ago. Accordingly, its global population size is likely to be relatively large.

Trend justification: No direct population trend data are available for this species, however remote sensing data are considered a suitable proxy for this forest-dependent species. Over the past ten years, forest cover within its range was reduced by c. 14-18% (Global Forest Watch [2024], based on data from Hansen et al. [2013] and methods therein). This species is commonest at lower elevations, where rates have been most rapid, and the species may be additionally impacted by forest degradation and fragmentation. Accordingly, rates of population reduction may be slightly higher than remote sensing data alone indicate; the rate of population reduction for the past three generations is set at 15-25%.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Brunei	extant	native	yes
Indonesia	extant	native	yes
Malaysia	extant	native	yes
Myanmar	extant	native	yes
Singapore	extinct	native	yes
Thailand	extant	native	yes

Country/Territory	IBA Name
Malaysia	Belum-Temenggor
Malaysia	Bintang Range
Malaysia	Central Titiwangsa Range
Malaysia	Crocker Range
Malaysia	Danum-Linau
Malaysia	Endau-Rompin
Malaysia	Gunung Penrissen
Malaysia	Hose-Laga mountains
Malaysia	Kabili-Sepilok
Malaysia	Krau Wildlife Reserve
Malaysia	Lambir Hills National Park
Malaysia	Lanjak Entimau Wildlife Sanctuary
Malaysia	Maliau Basin Conservation Area
Malaysia	Mulu - Buda Protected Area
Malaysia	Nakawan Range
Malaysia	Niah National Park
Malaysia	Panti forest
Malaysia	Selangor Heritage Park
Malaysia	Similajau National Park
Malaysia	South-east Pahang peat swamp forest
Malaysia	Taman Negara National Park
Malaysia	Ulu Muda
Thailand	Bala Sector, Hala-Bala Wildlife Sanctuary
Thailand	Hala Sector, Hala-Bala Wildlife Sanctuary and Bang Lang National Park
Thailand	Khao Banthad
Thailand	Khao Luang
Thailand	Khao Nor Chuchi
Thailand	Thaleban

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Artificial/Terrestrial	Subtropical/Tropical Heavily Degraded Former Forest	suitable	resident
Forest	Subtropical/Tropical Moist Lowland	major	resident
Wetlands (inland)	Permanent Rivers/Streams/Creeks (includes waterfalls)	suitable	resident
Altitude	0 - 1400 m	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%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture	Annual & perennial non-timber crops - Small-holder farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation
Agriculture & aquaculture	Wood & pulp plantations - Agro-industry plantations	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: (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		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation
Natural system modifications	Fire & fire suppression - Increase in fire frequency/intensity	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Ecosystem degradation, Ecosystem conversion

Purpose	Scale
Pets/display animals, horticulture	subsistence, national, international

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Recommended citation
BirdLife International (2024) Species factsheet: Grey-bellied Bulbul Ixidia cyaniventris. Downloaded from https://datazone.birdlife.org/species/factsheet/grey-bellied-bulbul-ixidia-cyaniventris on 23/12/2024.
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 23/12/2024.