Iole olivacea 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Pycnonotidae

Scientific Name: Iole olivacea
Species Authority: Blyth, 1844
Common Name(s):
English Buff-vented Bulbul

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Benstead, P., Gilroy, J., Taylor, J.
This species is relatively tolerant of secondary and degraded forest habitats, and therefore remains relatively common and widespread across much of its range. However, it is likely to be declining moderately rapidly overall as a result of widespread deforestation for timber and conversion to agriculture, and is therefore considered Near Threatened.

Previously published Red List assessments:
2008 Near Threatened (NT)
2004 Near Threatened (NT)
2000 Lower Risk/near threatened (LR/nt)
1994 Lower Risk/least concern (LR/lc)
1988 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description: Iole olivacea is restricted to the Sundaic lowlands of south Tenasserim, Myanmar, peninsular and west Thailand, Singapore (scarce), Sabah, Sarawak and Peninsular Malaysia, Kalimantan (including the Natuna and Anamba islands) and Sumatra (including offshore islands), Indonesia and Brunei, where it is generally a common bird in suitable habitats (BirdLife International 2001).

Countries occurrence:
Brunei Darussalam; Indonesia; Malaysia; Myanmar; Singapore; Thailand
Continuing decline in area of occupancy (AOO): Yes
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 1130000
Continuing decline in extent of occurrence (EOO): Yes
Extreme fluctuations in extent of occurrence (EOO): No
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Upper elevation limit (metres): 825
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The global population size has not been quantified, but the species is described as common, although very scarce in Singapore (del Hoyo et al. 2005).

Trend Justification:  This species is likely to be negatively influenced by the wholesale clearance of habitat taking place within its range, and is therefore suspected to be in moderately rapid decline overall.
Current Population Trend: Decreasing
Additional data:
Number of mature individuals: Unknown Continuing decline of mature individuals: Yes
Extreme fluctuations: No Population severely fragmented: No
Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Habitat and Ecology: This species is found in broadleaved evergreen forests in lowlands and hills, up to 825 m. It occurs in logged and secondary forests, as well as overgrown plantations and peat-swamp forest. It is most commonly encountered at forest edges or light-gaps within forest.

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Yes
Generation Length (years): 3.5
Movement patterns: Not a Migrant

Threats [top]

Major Threat(s): This species's tolerance of secondary and edge habitats suggests that it is not at immediate risk from habitat loss. However, it is inevitably affected by wholesale habitat clearance, which is occurring across large parts of the Sundaic region, with deliberate targeting of all remaining stands of valuable timber including those inside protected areas. Forest fires have also had a damaging effect (particularly in 1997-1998).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
No targeted conservation actions are known for this species, although it occurs in a number of protected areas.

Conservation Actions Proposed
Conduct repeated surveys within the species's range to assess population trends and rates of habitat loss. Conduct ecological studies to improve understanding of its precise habitat requirements, tolerance of secondary habitats and response to fragmentation. Increase the area of suitable primary forest with protected status and safeguard against on-going clearance. Improve the management of existing protected areas in the species's range. Designate forestry reserves in which only selective logging takes place. Encourage secondary growth and forest restoration in logged areas. Implement measures to reduce the number and severity of forest fires.

Citation: BirdLife International. 2012. Iole olivacea. The IUCN Red List of Threatened Species 2012: e.T22713170A38163443. . Downloaded on 02 December 2015.
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