Species

Justification
This species is listed as Vulnerable because it has a very small population. Although it may be at risk from the effects of introduced species, its population is presumed to have remained stable.

Taxonomic source(s)
Dowsett, R. J.; Forbes-Watson, A. D. 1993. Checklist of birds of the Afrotropical and Malagasy regions. Tauraco Press, Li

Taxonomic note
Hypsipetes borbonicus (Sibley and Monroe 1990, 1993) has been split into H. borbonicus and H. olivaceus following Dowsett and Forbes-Watson (1993).

Identification
22-23 cm. Large, black-capped bulbul. Greyish body, with pink bill and legs. Similar spp. Red-whiskered Bulbul Pycnonotus jocosus has obvious crest and white cheek patch. Voice Various nasal and wheezy calls. Hints Noisy, arboreal bird, usually seen in pairs or small parties (Cheke 1987b).

Distribution and population
Hypsipetes olivaceus is endemic to Mauritius, and is widespread at low densities over central and southern parts of the plateau. It was judged to have been reduced to c.200 pairs in the mid-1970s. In 1993, there were estimated to be 280 pairs, with the range and population probably stable since 1975 (Safford 1997c).

Population justification
In 1993, there were estimated to be 280 pairs (=560 mature individuals). This equates to roughly 840 individuals in total.

Trend justification
The species's range and population were probably stable between 1975 and 1993 (Safford 1997c), and it is presumed that they have remained stable since; the species is believed to be increasing in some areas and declining in others (V. Tatayah in litt. 2012).

Ecology
It occurs in nearly all native forests, favouring evergreen broadleaved forest (Cheke 1987b, Safford 1997c). It also forages in forest margins, degraded forest remnants with exotic trees, secondary scrub and exotic plantations (Safford 1996b). It is largely frugivorous but also takes some insects and geckos (Cheke 1987b). Nests have been found in low bushes (Cheke 1987b) and, more recently, 6-9 m up in Japanese red cedar Cryptomeria japonica (Safford 1996b). Densities are low (rarely over 10 pairs/km²), and are highest between Mt Cocotte and Combo (Safford 1997c), and down into lower Bel Ombre (C. Jones in litt. 2000). This is explained by the presence of wet, evergreen forest (C. Jones in litt. 2000).

Threats
Habitat degradation, through invasion by exotic plants, is the major threat in the long term (R. Safford in litt. 1999). Nest-predation and competition from introduced rats, crab-eating macaque Macaca fascicularis, P. jocosus and Common Mynah Acridotheres tristis are also threats. Competition may restrict H. olivaceus to native forest (Jones 1996).

Conservation actions underway
The Black River National Park partly covers its range (Jones and Hartley 1995). It has also responded well to rehabilitation of native ecosystems in Conservation Management Areas, which has included exclusion of introduced animals and replacement of exotic plants with native species (Safford and Jones 1998, C. Jones in litt. 2000).

Conservation actions proposed
Conduct population surveys, assessing distribution in relation to habitat-type and quality (C. Jones in litt. 2000). Continue rehabilitation of native forest (R. Safford in litt. 1999). Eventually, translocate birds to Mauritian islets, after rehabilitation of islet ecosystems and trial translocations of captive-reared birds over the next few years (Safford and Jones 1998, C. Jones in litt. 2000).

References
Cheke, A. S. 1987. The ecology of the smaller land-birds of Mauritius. In: Diamond, A.W. (ed.), Studies in Mascarene island birds, pp. 151-207. Cambridge University Press, Cambridge, U.K.

Jones, C. 1996. Bird introductions to Mauritius: status and relationships with native birds. In: Holmes, J.S.; Simons, J.R. (ed.), The introduction and naturalisation of birds, pp. 113-123. Joint Nature Conservation Committee, London.

Jones, C. G.; Hartley, J. 1995. A conservation project on Mauritius and Rodrigues: an overview and bibliography. Dodo: Journal of the Jersey Wildlife Preservation Trust 31: 40-65.

Safford, R. J. 1996. Notes on the biology of the Mauritius Black Bulbul Hypsipetes olivaceus. Ostrich 67: 151-154.

Safford, R. J. 1997. Distribution studies on the forest-living native passerines of Mauritius. Biological Conservation 80: 189-198.

Safford, R. J.; Jones, C. G. 1998. Strategies for land-bird conservation on Mauritius. Conservation Biology 12: 169-176.

Further web sources of information
View photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Ekstrom, J., McClellan, R., Pilgrim, J., Shutes, S., Symes, A., Taylor, J., Warren, B.

Contributors
Jones, C., Safford, R., Tatayah, V.

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

Recommended citation
BirdLife International (2013) Species factsheet: Hypsipetes olivaceus. Downloaded from http://www.birdlife.org on 19/06/2013. Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 19/06/2013.

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.

Additional resources for this species

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