Wednesday 15 May
Dwarf olive ibis (Bostrychia bocagei)
Dwarf olive ibis fact file
- Find out more
- Print factsheet
Dwarf olive ibis description
Until its rediscovery in 1990, the only evidence for the continued existence of the dwarf olive ibis was from historical reports and anecdotes from hunters (2). Believed to be the world’s smallest ibis (3), this Critically Endangered species can be identified by the bare patches of black skin on the face and the large crest extending from the back of the head (4). The plumage is generally brownish, with a bronze sheen on the upperparts, and an olive hue on the head. Like other ibises, the dwarf olive ibis has a long, thin bill that curves downwards and, in this species, is coloured brown, becoming reddish towards the tip. Although often silent, when disturbed the dwarf olive ibis will make unusual cough-like grunts, while at other times it produces a kah gah kah gah call (2).
- Length: 60 – 65 cm (2)
Dwarf olive ibis biology
In common with many other ibises, the dwarf olive ibis uses its long curved bill to probe within the soil and amongst rock crevices for its invertebrate prey. Generally, it prefers to forage in rocky, swampy areas of the forest with sparse undergrowth, or where the ground has been overturned by foraging wild pigs (2).
The dwarf olive ibis is usually found alone or in small flocks which roost together at night, announcing their entrance and exit from the roosting site with a harsh honking noise (2) (4). Little is currently known about this species’ reproduction, but a single nest was found in 1997 in a tree overhanging water (2).Top
Dwarf olive ibis rangeTop
Dwarf olive ibis habitatTop
Dwarf olive ibis status
Classified as Critically Endangered (CR) on the IUCN Red List (1).Top
Dwarf olive ibis threats
The historical clearance of much of Sao Tomé’s lowland forest for sugar cane and cocoa plantations undoubtedly had a catastrophic impact on the dwarf olive ibis’s population (2) (5) (6). While today large-scale clearance for plantations has mostly stopped (2) (5), forest clearance for small farms continues, and there is also the possibility that exploitation of primary forest for timber and firewood will increase dramatically in the future (5). In addition, this species is severely affected by hunting and predation from introduced mammals such as the mona monkey (Cercopithecus mona), African civet (Civettictis civetta) and weasel (Mustela nivalis) (2). With its population estimated in 2007 to be between 50 and 249 individuals, the combined effects of these threats are rapidly pushing the dwarf olive ibis towards extinction (2).Top
Dwarf olive ibis conservation
There are currently no conservation measures in place for the dwarf olive ibis. While various organisations have proposed that this species and its habitat should be given protected status, this has yet to occur (2) (6). Without intervention, this unique species, found nowhere else in the world, could disappear forever (2).Top
Find out more
To learn more about Sao Tomé’s unique wildlife and the threats it faces visit:
- Gulf of Guinea Conservation Group:
For more information on this and other bird species please see:
- BirdLife International:
AuthenticationThis information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: firstname.lastname@example.orgTop
- A species or taxonomic group that is only found in one particular country or geographic area.
- Ananimal with no backbone.
- Primary forest
- Forest that has remained undisturbed for a long time and has reached a mature condition.
- IUCN Red List (December, 2008)
- BirdLife International (December, 2008)
- Melo, M. (2004) Bird speciation in the Gulf of Guinea, West Africa. Genetics Society News, 51: 50 - 53.
- del Hoyo, J., Elliott, A. and Sargatal, J. (1992) Handbook of the Birds of the World. Volume 1: Ostrich to Ducks. Lynx Edicions, Barcelona.
- Peet, N. and Atkinson, P. (1994) Biodiversity and conservation of the birds in Sao Tomé and Principe. Biodiversity and Conservation, 3: 851 - 868.
- WWF (December, 2008)
MyARKive offers the scrapbook feature to signed-up members, allowing you to organize your favourite ARKive images and videos and share them with friends.
Terms and Conditions of Use of Materials
Copyright in this website and materials contained on this website (Material) belongs to Wildscreen or its licensors.
Visitors to this website (End Users) are entitled to:
- view the contents of, and Material on, the website;
- download and retain copies of the Material on their personal systems in digital form in low resolution for their own personal use;
- teachers, lecturers and students may incorporate the Material in their educational material (including, but not limited to, their lesson plans, presentations, worksheets and projects) in hard copy and digital format for use within a registered educational establishment, provided that the integrity of the Material is maintained and that copyright ownership and authorship is appropriately acknowledged by the End User.
End Users shall not copy or otherwise extract, alter or manipulate Material other than as permitted in these Terms and Conditions of Use of Materials.
Additional use of flagged material
Green flagged material
Certain Material on this website (Licence 4 Material) displays a green flag next to the Material and is available for not-for-profit conservation or educational use. This material may be used by End Users, who are individuals or organisations that are in our opinion not-for-profit, for their not-for-profit conservation or not-for-profit educational purposes. Low resolution, watermarked images may be copied from this website by such End Users for such purposes. If you require high resolution or non-watermarked versions of the Material, please contact Wildscreen with details of your proposed use.
Creative commons material
Certain Material on this website has been licensed to Wildscreen under a Creative Commons Licence. These images are clearly marked with the Creative Commons buttons and may be used by End Users only in the way allowed by the specific Creative Commons Licence under which they have been submitted. Please see http://creativecommons.org for details.
Any other use
Please contact the copyright owners directly (copyright and contact details are shown for each media item) to negotiate terms and conditions for any use of Material other than those expressly permitted above. Please note that many of the contributors to ARKive are commercial operators and may request a fee for such use.
Save as permitted above, no person or organisation is permitted to incorporate any copyright material from this website into any other work or publication in any format (this includes but is not limited to: websites, Apps, CDs, DVDs, intranets, extranets, signage, digital communications or on printed materials for external or other distribution). Use of the Material for promotional, administrative or for-profit purposes is not permitted.