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Yellow-bearded Greenbul Criniger olivaceus

Justification
Forest throughout this species's known range is fast disappearing and its population could still be rapidly declining, and is certainly becoming increasingly fragmented. It is therefore classified as Vulnerable.

Taxonomic source(s)
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

Taxonomic note
Criniger olivaceus and C. ndussumensis (Sibley and Monroe 1990, 1993) are retained as separate species contra Dowsett and Forbes-Watson (1993) who include ndussumensis as a subspecies of C. olivaceus.

Identification
20 cm. Medium-sized, drab greenbul. Dark olive relieved only by yellow throat. Faintly paler olive on belly and vent with a hardly discernible rusty wash on tail. Paler lores and blue eye-ring (hardly noticeable in the field). Similar spp. Could be confused with Western Bearded Greenbul C. barbatus but is smaller and has green, not greyish-brown, underparts, and less puffy throat. Voice Soft chuk given whilst foraging and three harsh notes whut chruw chruw. Hints Usually occurs in groups of between two and, rarely, five birds in mixed-species flocks and has distinctive habit of foraging on vertical trunks and branches.

Distribution and population
Criniger olivaceus is known from several sites in southeast Guinea (L. Fishpool in litt. 2007, 2012, H. Rainey in litt. 2007), Sierra Leone (areas include Gola Forest where locally common, population 750-1,600 birds, Loma Forest [Atkinson et al. 1996b] and the Kangari Hills [P. Robertson in litt. 1998]), Liberia (from the coast to the northern border at Nimba, population c.120,000 pairs [Gatter 1997]), Côte d'Ivoire (Taï National Park where frequently recorded during surveys in 2001-2002 [H. Rainey in litt. 2007], Yapo Forest where common [Demey and Fishpool 1994, H. Rainey in litt. 1999], Haute Dodo and Cavally Forest reserves where rarely observed [H. Rainey in litt. 2007], Mabi Forest [Waltert et al. in press], Mopri and possibly in Mont Peko National Park [H. Rainey in litt. 2007]), and Ghana (rediscovered in the 1980s, and restricted to the wetter evergreen forests of the southwest). In Ghana in particular, the species was found to be more common than originally thought (Holbech 1992, 1996, Ntiamoa-Baidu and Owusu 2001). However, some sightings may relate to misidentifications (L. Fishpool in litt. 2007).

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.

Trend justification
The population is suspected to be declining rapidly, in line with the clearance of forest within the species's range for commercial timber extraction and agriculture.

Ecology
It is found in the midstorey of lowland primary forest. In Liberia, it is also known from mature secondary forest, forest-grassland mosaic and gallery forest and is found in the northern mountains up to 800 m (Gatter 1997). In Côte d'Ivoire, it is found in most primary forest in Taï National Park, but is more common in the evergreen forest of Yapo Forest, possibly owing to the greater prevalence of dense understorey and epiphytes (Gartshore et al. 1995). It is mainly insectivorous.

Threats
The largest remaining area of Upper Guinea forest (43%) is now found in Liberia, where it is under intense pressure, particularly since the end of the civil war in 1996, when there was a sharp increase in commercial logging activities (Anon. 2000). Large scale deforestation (in 1990 estimated to be c.6% annually) has already taken place in Côte d'Ivoire, particularly since the mid-1970s, and has been encroaching on protected areas (Chatelain et al. 1996). Forests on the Guinea and Côte d'Ivoire border, near Mt Nimba, have little effective protection and clearance for agriculture and logging is taking place rapidly (H. Rainey in litt. 2007). The rate of forest loss in the Upper Guinea region appears to have declined slightly in recent years, owing mostly to a decrease in the rate of deforestation in Côte d'Ivoire, which may increase with the return of peace (H. Rainey in litt. 2007). Across the Upper Guinea region, forest survives in fragmented patches which are under intense pressure for logging and agriculture (Anon. 2000).

Conservation Actions Underway
Taï National Park and periphery (including Haute Dodo and Cavally Forest Reserves) in Côte d'Ivoire is the largest and best-preserved area of Upper Guinea forest, but management needs improvement (H. Rainey in litt. 2007). In Sierra Leone Gola Rainforest National Park was officially designated in 2010. Conservation Actions Proposed
Improve management of Taï National Park and periphery (H. Rainey in litt. 2007). Carry out surveys in order to assess the species's population size, once the security situation is conducive. Monitor rates of forest clearance across the species's range. In Taï National Park, take measures to mitigate the effects of rapid land-use changes outside the park (Gartshore et al. 1995). In Taï National Park and Gola Forest, take action to limit forest clearance and incorporate local people in to development of effective management plan including development of land use regulations, alternative livelihoods, ecotourism and other activities which will limit encroachment into park (H. Rainey in litt. 2007). Effectively motivate forest guards to carry out patrols (H. Rainey in litt. 2007).

References
Atkinson, P.; Turner, P.-A.; Pocknell, S.; Broad, G.; Koroma, A. P.; Annaly, D.; Rowe, S. 1996. Landuse and conservation in the Mount Loma Reserve, Sierra Leone. Report of the University of East Anglia - BirdLife International expedition to the Mount Loma reserve in north-eastern Sierra Leone (January-April 1992).

Chatelain, C.; Gautier, L.; Spichiger, R. 1996. A recent history of forest fragmentation in southwestern Ivory Coast. Biodiversity and Conservation 5(1): 37-53.

Collar, N. J.; Stuart, S. N. 1985. Threatened birds of Africa and related islands: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, and International Union for Conservation of Nature and Natural Resources, Cambridge, U.K.

Demey, R.; Fishpool, L. D. C. 1994. The birds of Yapo forest, Ivory Coast. Malimbus 16: 100-122.

Gartshore, M. E.; Taylor, P. D.; Francis, I. S. 1995. Forest birds in Côte d'Ivoire. BirdLife International, Cambridge, U.K.

Gatter, W. 1997. Birds of Liberia. Pica Press, Robertsbridge, UK.

Holbech, L. H. 1996. Faunistic diversity and game production contra human activities in the Ghana high forest zone, with reference to the Western Region.

Ntiamoa-Baidu, Y.; Owusu, E. H.; Daramani, D. T.; Nuoh, A. A. 2001. Ghana. In: Fishpool, L.D.C.; Evans, M.I. (ed.), Important Bird Areas in Africa and associated islands: Priority sites for conservation, pp. 367-389. Pisces Publications and BirdLife International (BirdLife Conservation Series No.11), Newbury and Cambridge, UK.

Waltert, M.; Yaokokore-Beibro, K. H.; Mühlenberg, M.; Waitkuwait, W. E. 1999. Preliminary check-list of the birds of the Bossematié area, Ivory Coast. Malimbus 21: 93-109.

Further web sources of information
Explore HBW Alive for further information on this species

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Text account compilers
Ekstrom, J., Shutes, S., Starkey, M., Symes, A., Taylor, J.

Contributors
Fishpool, L., Rainey, H., Robertson, P., Thompson, H.

IUCN Red List evaluators
Butchart, S., Taylor, J.

Recommended citation
BirdLife International (2014) Species factsheet: Criniger olivaceus. Downloaded from http://www.birdlife.org on 18/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/12/2014.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Key facts
Current IUCN Red List category Vulnerable
Family Pycnonotidae (Bulbuls)
Species name author (Swainson, 1837)
Population size mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 231,000 km2
Country endemic? No
Links to further information
- Additional Information on this species
- Projected distributions under climate change