Justification of Red List Category
This species qualifies as Endangered because it is thought to have a small population and occupies a small area of suitable primary and mature secondary forest habitat within its range.
The species was recently split from São Tomé White-eye (Zosterops feae) (del Hoyo and Collar 2016). 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 equivalent to 375-1,499 individuals in total, rounded here to 350-1,500 individuals. The estimate 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. All individuals are thought to belong to the same subpopulation. Notably, given how restricted its range is, the population size could in fact be lower.
At the beginning of the 20th century, the species was considered quite common on the island (Hering et al. 2018). Declines were recorded from 1970 on, when primary and mature forests were increasingly cleared for agriculture and housing development. The species is likely intolerant of forest loss and degradation, and as such may be declining.
Zosterops ficedulinus is endemic to Príncipe, São Tomé e Príncipe. It occurs in mature forests in the central massif in the south and west of the island (Christy and Clarke 1998, Dallimer et al. 2012), with a recent record from the south-east (J. Baillie and A. Gascoigne in litt. 2000).
The species is thought to be restricted to primary forest and forest edge in the hilly interior of the southern part of the island of Príncipe (J. Baillie and A. Gascoigne in litt. 2000, van Balen 2018). Additionally, there are records from more degraded habitats elsewhere on the island (Hering et al. 2018), and it may potentially use the tallest trees in plantations (van Balen 2018). However, surveys by Dallimer et al. (2012) failed to locate the species in any habitat apart from primary rainforest. The species is usually found in small groups, often in mixed-species parties and is insectivorous.
Historically, large areas of primary 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. Limited areas of secondary and primary forest are threatened by clearance for cultivation, timber and fuelwood-collection (Atkinson et al. 1991). Dallimer et al. (2012) failed to find the species in either secondary forest or agricultural land, only locating the species in primary rainforest, suggesting that the species is intolerant of habitat alteration. Therefore, even if its habitat hasn’t been outright destroyed, any degradation of primary forest could lead to the disappearance of this species. 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).
Conservation Actions Underway
Large parts of the species's range lie within the boundaries of Príncipe Ôbo Natural Park, which is surrounded by extensive tracts of secondary forest and abandoned plantations, thereby buffering logging activities outside (Hering et al. 2018). 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).
10.5 cm. Dark brown head with greyish-white sides and olive-brown neck, bright white eyering; dark olive-green upperparts, rump and uppertail-coverts greenish; underparts whitish, tinged yellow, throat and upper breast streaked dusky. Similar spp Slightly different colouration than São Tomé White-eye (Z. feae); less brightly coloured than Z. feae, with duller green upperparts and white underparts.
Text account compilers
Shutes, S., Ekstrom, J., Hermes, C., Peet, N., Starkey, M., Symes, A., Taylor, J., Westrip, J.
Gascoigne, A., Baillie, J., Olmos, F., Melo, M.
BirdLife International (2021) Species factsheet: Zosterops ficedulinus. Downloaded from http://www.birdlife.org on 24/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 24/10/2021.