VU
Yellow-bearded Greenbul Criniger olivaceus



Taxonomy

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.

IUCN Red List criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - A2bc+3bc+4bc

Red List history
Year Category Criteria
2020 Vulnerable A2bc+3bc+4bc
2018 Vulnerable A2c+3c+4c
2016 Vulnerable A2c+3c
2012 Vulnerable A2c+3c+4c
2008 Vulnerable A2c; A3c; A4c
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened
Species attributes

Migratory status not a migrant Forest dependency medium
Land-mass type continent
Average mass 28 g
Range

Estimate Data quality
Extent of Occurrence (breeding/resident) 373,000 km2 medium
Severely fragmented? no -
Population
Estimate Data quality Derivation Year of estimate
Population size 66700-333000 mature individuals poor suspected 2007
Population trend decreasing medium inferred 2012-2022
Rate of change over the past 10 years/3 generations (longer of the two periods) 30-49% - - -
Rate of change over the future 10 years/3 generations (longer of the two periods) 30-49% - - -
Rate of change over the past & future 10 years/3 generations (longer of the two periods) 30-49% - - -
Generation length 3.1 years - - -

Population justification: The total population is conservatively suspected to number somewhere in the region of 100,000-499,999 individuals based on a population of c.120,000 pairs in Liberia alone (Gatter 1997). This roughly equates to 66,667 - 333,333 mature individuals, here rounded to 66,700 - 333,000 mature individuals.

Trend justification: The population is inferred to be in decline owing to ongoing habitat destruction and fragmentation. Global Forest Change data on tree cover loss indicate that, over ten years to 2019, approximately 6.5% of tree cover with 75% canopy cover was lost from within the species’s range (Global Forest Watch 2020). However, the species's habitat is also subject to commercial logging, which may not be detected by remote-sensed data, but which may change the structure of the habitat and have a negative impact on the species's population (B. Phalan in litt. 2020). Arcilla et al., (2015) reported a capture rate of 2.70 Yellow-bearded Greenbuls per 10,000 net-metre-hours in Ghana in 1993-1995, and this fell to zero in 2008-2010, following a period when logging activity increased. The species's population is therefore precautionarily suspected to have undergone a reduction of more than 30% over the past ten years, placed here in the band 30-49%. The threats to the species are ongoing, so this rate of decline is suspected to continue into the future.


Country/territory distribution
Country/Territory Presence Origin Resident Breeding visitor Non-breeding visitor Passage migrant
Côte d'Ivoire extant native yes
Ghana extant native yes
Guinea extant native yes
Liberia extant native yes
Sierra Leone extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Côte d'Ivoire Mount Nimba Strict Nature Reserve
Côte d'Ivoire Mabi Forest reserve
Côte d'Ivoire Parc National de Taï et Réserve de faune du N'Zo
Côte d'Ivoire Mopri Forest Reserve
Côte d'Ivoire Yapo and Mambo Forest Reserves
Ghana Ankasa Resource Reserve - Nini-Sushien National Park
Ghana Atewa Range Forest Reserve
Ghana Bia National Park and Resource Reserve
Ghana Boin Tano Forest Reserve
Ghana Boin River Forest Reserve
Ghana Bura River Forest Reserve
Ghana Cape Three Points Forest Reserve
Ghana Dadieso Forest Reserve
Ghana Draw River Forest Reserve
Ghana Ebi River Shelterbelt Forest Reserve
Ghana Fure River Forest Reserve
Ghana Jema-Asemkrom Forest Reserve
Ghana Kakum National Park - Assin Attandaso Resource Reserve
Ghana Subri River Forest Reserve
Ghana Tano-Anwia Forest Reserve
Ghana Tano-Ehuro Forest Reserve
Ghana Tano-Nimiri Forest Reserve
Ghana Tano-Offin Forest Reserve
Guinea Massif du Ziama
Guinea Diécké
Liberia Wologizi mountains
Liberia Wonegizi mountains
Liberia Lofa-Gola-Mano Complex
Liberia Nimba mountains
Liberia Zwedru
Liberia Cestos - Senkwen
Liberia Sapo
Liberia Grebo
Sierra Leone Loma Mountains Non-hunting Forest Reserve
Sierra Leone Gola Forests

Habitats & altitude
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
Altitude 0 - 800 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%) Rapid Declines Medium Impact: 7
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Annual & perennial non-timber crops - Small-holder farming Timing Scope Severity Impact
Ongoing Majority (50-90%) Rapid Declines Medium Impact: 7
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Rapid Declines Medium Impact: 7
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%) Rapid Declines Medium Impact: 7
Stresses
Ecosystem degradation, Ecosystem conversion
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Future Majority (50-90%) Slow, Significant Declines Low Impact: 4
Stresses
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

Recommended citation
BirdLife International (2024) Species factsheet: Criniger olivaceus. Downloaded from https://datazone.birdlife.org/species/factsheet/yellow-bearded-greenbul-criniger-olivaceus on 28/02/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org on 28/02/2024.