Data Zone
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.
| Critically Endangered | Endangered | Vulnerable |
|---|---|---|
| - | - | A2bc+3bc+4bc |
| 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 |
| Migratory status | not a migrant | Forest dependency | medium |
| Land-mass type |
continent |
Average mass | 28 g |
| Estimate | Data quality | |
|---|---|---|
| Extent of Occurrence (breeding/resident) | 373,000 km2 | medium |
| Severely fragmented? | no | - |
| 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 | 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 |
| 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 |
| 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 | ||||||
|
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| Agriculture & aquaculture | Annual & perennial non-timber crops - Small-holder farming | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Rapid Declines | Medium Impact: 7 | ||||||
|
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| Biological resource use | Logging & wood harvesting - Unintentional effects: (large scale) [harvest] | Timing | Scope | Severity | Impact | ||||
| Ongoing | Majority (50-90%) | Rapid Declines | Medium Impact: 7 | ||||||
|
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| 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 | ||||||
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| Climate change & severe weather | Habitat shifting & alteration | Timing | Scope | Severity | Impact | ||||
| Future | Majority (50-90%) | Slow, Significant Declines | Low Impact: 4 | ||||||
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| Energy production & mining | Mining & quarrying | Timing | Scope | Severity | Impact | ||||
| Ongoing | Minority (<50%) | Slow, Significant Declines | Low Impact: 5 | ||||||
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Recommended citation
BirdLife International (2024) Species factsheet: Yellow-bearded Greenbul Criniger olivaceus. Downloaded from
https://datazone.birdlife.org/species/factsheet/yellow-bearded-greenbul-criniger-olivaceus 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.