Giant Sunbird Dreptes thomensis


Justification of Red List Category
This species qualifies as Vulnerable because it is likely to have a small population, given the limited area of suitable primary forest habitat within its range.

Population justification
The population is estimated to number 250-999 mature individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 375-1,499 individuals in total, rounded here to 350-1,500 individuals.

Trend justification
Clearance of primary forest may be impacting this species, but is currently limited. Therefore, the species is precautionarily suspected to be decreasing.

Distribution and population

Dreptes thomensis is endemic to São Tomé, São Tomé e Príncipe, where it occurs on the central massif, north towards Ponta Figo, south-west to the area around the rivers São Miguel, Xufexufe and Quija and east to Formoso Grande and the Formoso Pequeno and the valley of the Ana Chaves river (Atkinson et al. 1991, Christy and Clarke 1998). It is locally common, but its population is probably small given the area of available habitat. De Oliveira Soares (2017) observed this species at 244 point counts out of a total of 3,056.


It occurs in both lowland and montane primary forest up to at least 2,000 m, with occasional records from forest-edge cultivation. It feeds on invertebrates, both from moss and lichen-covered branches and from probing in bark, and also on nectar from flowers. Nests have been found in late December and early January (Atkinson et al. 1991, Christy and Clarke 1998).


Historically, large areas of lowland and mid-altitude forest were cleared for cocoa and coffee plantations. Land privatisation is leading to an increase in the number of small farms and clearance of trees. This is not thought to currently affect primary forest but may be a threat in the future (A. Gascoigne in litt. 2000). Limited areas of secondary and primary forest, particularly in the north of its range, are threatened by clearance for cultivation, timber and fuelwood-collection (Atkinson et al. 1991). Construction for the country's developing oil industry, including the established idea of building 'free ports' (free economic zones) (M. Melo in litt. 2003), was seen as a potential threat to the species's habitat. However, prospecting on land was unsuccessful, and any construction is likely to be offshore (F. Olmos in litt. 2007). Road developments along the east and west coasts are increasing access to previously remote areas (A. Gascoigne in litt. 2000).

Conservation actions

Conservation Actions Underway
Primary forest is protected as a zona ecologica and in the 295-km2 Obô Natural Park, although there is no law enforcement within these areas (F. Olmos in litt. 2007, A. Ward-Francis in litt. 2016). The park was established in 1992, but was not protected by law until 2006, and although a zoning and management plan was being developed in 2008, when the first directors were appointed, the park was still lacking sufficient personnel (Olmos and Turshak 2010). A new law providing for the gazetting of protected areas and the protection of threatened species (A. Gascoigne in litt. 2000, M. Melo in litt. 2003) has been ratified (F. Olmos in litt. 2007). In 2008, a training programme with NGOs Associação de Biólogos Saotomenses (ABS) and Monte Pico was initiated to involve locals in the study and conservation of São Tomean species (A. Ward-Francis in litt. 2016). Through the BirdLife Preventing Extinctions Programme, there has been an active programme of research on the forest birds and globally threatened endemic biodiversity of São Tomé island from 2012, that this species has been a beneficiary of. This research has gathered information on distributions, habitat associations, threats of endemic forest birds. Outcomes from this work are currently being analysed (A. Ward-Francis in litt. 2016). In addition, during this time, a series of meetings and workshops have been held with Government staff, local communities and agricultural companies, to identify solutions to threats to forest biodiversity.  Going forward, this species will benefit from a planned programme of work, led by BirdLife International, SEPA and RSPB, which will 1) seek improved integration of the Obô Natural Park within existing national legislation, policies and plans; 2)  develop park infrastructure, staffing, enforcement and monitoring; 3) identify sustainable financing opportunities for park implementation, and 4) support developing in-country capacity for conservation (A. Ward-Francis in litt. 2016). 

Conservation Actions Proposed
Research its population size and distribution. Study its ecological requirements. Investigate key threats in order to produce conservation recommendations. Ensure legal protection of all remaining lowland primary forest, and ensure the practices of the protected area of Obô Natural Park are implemented properly. List it as a protected species under national law.


15-17 cm. Very large sunbird. Overall matt black with deep blue and purple iridescence. Pale yellow vent and long, graduated tail tipped white. Long, decurved bill. Voice Harsh two-three note chik chik and jumbled series of harsh and softer notes.


Text account compilers
Ekstrom, J., Peet, N., Shutes, S., Benstead, P., Starkey, M., Symes, A., Taylor, J., Westrip, J.

de Lima, R., Melo, M., Ward-Francis, A., Olmos, F., , A., Gascoigne, A.

Recommended citation
BirdLife International (2019) Species factsheet: Dreptes thomensis. Downloaded from on 23/08/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from on 23/08/2019.