Sao Tome grosbeak (Neospiza concolor)
|Also known as:||Sao Tome canary, Sao Tome goldfinch|
|French:||Grosbec de São Tomé|
|Size||Length: 18 cm (2)|
Classified as Critically Endangered (CR) on the IUCN Red List (1).
Prior to its rediscovery in 1991, the São Tomé grosbeak was known from just a single specimen collected in the late 19th century (2) (3) (4) (5). At around 18 centimetres, the São Tomé grosbeak is relatively large for a finch, with a plump body, and a massive, greyish-buff bill, with which it effortlessly crushes seeds. The plumage is uniformly rusty brown, but is slightly darker on the head, wings and tail (2).
The São Tomé grosbeak is endemic to the island of São Tomé in the Gulf of Guinea, 255 kilometres off the coast of Gabon. It was rediscovered close to the rio Xufexufe in the south-west of the island, and has been reported from this locality on several occasions since, as well as the from other sites in the centre and southeast of the island (2) (3).
Inhabits lowland, closed-canopy primary forest (2) (3).
As may be expected for such a historically elusive species, very little has been reported on the natural history of the São Tomé grosbeak. Aside from its small population size, one of the possible reasons this species is so rarely seen is that it keeps to the canopy and rarely makes much noise. It appears to move about in pairs, or alone, and descends to the understorey to feed on seeds (2).
Forest clearance began on São Tomé in the late 15th century, when early colonisers made space for the cultivation of sugar cane. In the 1800s, the rate of deforestation accelerated dramatically, first with the production of coffee and later with cocoa. At one stage in the early 20th century, São Tomé was the world’s largest producer of cocoa, with an estimated 42 percent of the island being devoted to its production. The crash in the price of cocoa, and the island’s conversion to independence in 1975, put a stop to forest clearance but not before almost all the island’s lowland primary forest had been destroyed (3). Naturally, this had a devastating impact on much of the endemic wildlife, including the São Tomé grosbeak population (2) (3). Today, the population is estimated at less than 50 individuals, restricted to habitat under increasing pressure from land privatisation (2) (4). Furthermore, road developments along the east and west coasts are increasing access to previously remote areas, while introduced rats, monkeys, weasels and civets are all potential predators (2) (3).
Primary forest is protected as a Zona Ecologica and within Obo Natural Park, but there is no law enforcement within these areas, and owing to the lack of information on the São Tomé grosbeak’s ecological requirements, it is not known how much it benefits from its occurrence within these areas. Fortunately, this species mainly occurs in a relatively remote part of the island, visited only by hunters, who do not pose a threat to it. Recently, the Associação dos Biólogos Santomenses has been offering training course to the local community in order to raise awareness, and involve people in the monitoring and conservation of São Tomé’s endemic birds. Further research into this Critically Endangered species’ population size, distribution and ecological requirements is now needed to refine conservation measures. Proposals have also been made to ensure the effective protection of designated areas, and to list the São Tomé grosbeak as a protected species under national law (2) (5).
For further information on the São Tomé grosbeak see:
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- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Primary forest: forest that has remained undisturbed for a long time and has reached a mature condition.
IUCN Red List (February, 2010):
BirdLife International (February, 2010)
- Peet, N. and Atkinson, P. (1994) Biodiversity and conservation of the birds in São Tomé and Príncipe. Biodiversity and Conservation, 3(9): 851 - 868.
- Perrins, C. (2009) The Encyclopedia of Birds. Oxford University Press, Oxford.
- Hirschfeld, E. (2008) Rare Birds Yearbook 2009. MagDig Media Limited, UK.