VU
Yellow-bearded Greenbul Criniger olivaceus



Justification

Justification of Red List Category
Forest throughout this species' 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.

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).

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

Distribution and population

The species 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. 1996] 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 (restricted to the wetter section of the forest zone of the south-west, being fairly common in Ankasa and Cape Three Points, and local elsewhere (Holbech 2005, Dowsett-Lemaire and Dowsett 2014)

Ecology

The species 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. In Ghana, it appears localised and requires closed canopy habitats (Dowsett-Lemaire and Dowsett 2009). It feeds mainly at mid-levels, occasionally lower, probing bark of branches and lianas, occasionally also foliage (Fishpool 2008, Dowsett-Lemaire and Dowsett 2014).

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 (van der Mark 2000) and large scale oil-palm plantations (F. Dowsett-Lemaire in litt. 2016). 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). In Ghana it is threatened by deforestation and even selective logging as it can no longer be found in heavily-logged sections of some forest reserves where it occurred previously (Dowsett-Lemaire and Dowsett 2014) and in Ghana, it is only protected in Ankasa Wildlife Reserve and Kakum National Park (Dowsett-Lemaire and Dowsett 2014). The rate of forest loss in the Upper Guinea region appeared to decline slightly owing primarily to a decrease in the rate of deforestation in Côte d'Ivoire, but this may have increased with the return of peace (H. Rainey in litt. 2007, R. Demey per F. Dowsett-Lemaire in litt. 2016). Across the Upper Guinea region, forest survives in fragmented patches which are under intense pressure for logging and agriculture (van der Mark 2000), and possible mining (Deikumah et al. 2014). This species may be affected by the impacts of climate change (Baker and Willis 2014, Carr et al. 2014).

Conservation actions

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' population size, once the security situation is conducive. Monitor rates of forest clearance across the species' 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 the park (H. Rainey in litt. 2007). Effectively motivate forest guards to carry out patrols (H. Rainey in litt. 2007).

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.

Acknowledgements

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

Contributors
Demey, R., Robertson, P., Dowsett-Lemaire, F., Rainey, H., Dowsett, R.J., Thompson, H.S., Fishpool, L.


Recommended citation
BirdLife International (2020) Species factsheet: Criniger olivaceus. Downloaded from http://www.birdlife.org on 28/11/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 28/11/2020.