Justification This species qualifies as Vulnerable because it is thought to have a small population, given the small area of suitable primary and mature secondary forest habitat within its range. Improved knowledge of its population and habitat requirements may result in its population estimate being revised upwards and its status being reviewed.

Family/Sub-family Oriolidae

Species name author Hartlaub, 1857

Taxonomic source(s) Dowsett and Forbes-Watson (1993), Sibley and Monroe (1990, 1993)

Identification 20-22 cm. Forest-dwelling oriole. Male has black head, pale olive upperparts with darker wings and tail. Pale yellow upper and undertail-coverts with golden-yellow tips to tail feathers. Silky white remainder of underparts. Female lacks black head and has streaking across the breast. Juvenile similar to female but lacks yellow on tail and is more heavily streaked on underparts. Pink-red bill. Voice Melodic ou-huu, or hui-yiioouh, or hu-ou-hu.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

250-999

stable

480 km²

Yes

Range & population Oriolus crassirostris is endemic to São Tomé, São Tomé e Príncipe. It is widely distributed over much of the island, except the north-east, and is most abundant in the south-west and on the central massif, occurring everywhere at low densities, with old estimates of one to two birds per 25 ha^1,2.

Important Bird Areas Click here to view map showing IBAs where species is recorded and triggers any of the IBA criteria.

Ecology: It is most abundant in primary forest (up to 1,600 m), but also occurs in undisturbed secondary forest. It occurs occasionally in dry forest in the north but is generally absent from cocoa plantations^1,2.

Threats Historically, large areas of forest were cleared for cocoa and coffee plantations. Today, land privatisation is leading to an increase in the number of small farms and the clearance of trees and may be a threat to this species where it occurs in secondary habitats. Road developments along the east and west coasts are increasing access to previously remote areas³. Construction for the country's developing oil industry, including the established idea of building 'free ports' (free economic zones)⁴, was seen as a potential threat to the species's habitat. However, prospecting on land was unsuccessful, and any construction is likely to be offshore⁵.

Conservation measures underway A new law providing for the gazetting of protected areas and the protection of threatened species^3,4 has been ratified⁵. Legislation for the creation of Obo National Park has also been ratified⁵ and protection of primary forest as a zona ecologica has been proposed.

Conservation measures proposed Research its population size and distribution. Study its ecological requirements. Identify the key threats in order to produce conservation recommendations. Ensure legal protection of all remaining lowland primary forest. List it as a protected species under national law.

References 1. Atkinson et al. (1991). 2. Christy and Clarke (1998). 3. A. Gascoigne in litt. (2000). 4. M. Melo in litt. (2003). 5. F. Olmos in litt. (2007).

Text account compilers Jonathan Ekstrom (BirdLife International), Nic Peet (BirdLife International), Sue Shutes (BirdLife International), Malcolm Starkey (BirdLife International), Joe Taylor (BirdLife International)

Contributors Angus Gascoigne (Gulf of Guinea Conservation Group), Martim Melo (University of Edinburgh), Fabio Olmos

IUCN Red List evaluators Stuart Butchart (BirdLife International), Joe Taylor (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Oriolus crassirostris. Downloaded from http://www.birdlife.org on 10/2/2010

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.

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