Data Zone
Justification of Red List category
This species is classified as Near Threatened because it is restricted to one extremely small island where it is thought to have become scarcer in recent years. It would warrant uplisting to a higher threat category if alien predators, such as brown tree-snake Boiga irregularis, were to become established on Yap.
Population justification
Engbring et al. (1990) estimated 19,619 individuals, which is rounded to 19,600 individuals here, roughly equivalent to 13,000 mature individuals; it is thought to have become scarcer since.
Trend justification
There are no actual trend data, but D. Pratt in litt (1994) considered the species to have become scarcer in recent years.
Zosterops oleagineus is endemic to the four islands of Yap, Federated States of Micronesia. In the 1970s, it could be readily found in any forest area (H. D. Pratt in litt. 1994). In 1984, it was estimated to have a total population of 19,619 individuals and was expected to remain common (Engbring et al. 1990). However, more recently, it appears to have become scarcer (H. D. Pratt in litt. 1994). Tracewski et al. (2016) estimated the maximum Area of Occupancy (calculated as the remaining tree area within the species’s range) to be c.32 km2.
It is widely distributed in all types of forest and woody vegetation, including mangroves, but shows a preference for better-developed forests (Engbring et al. 1990).
Loss of habitat from fire is a threat as local people set fire to large areas of savanna during the dry season (B. Raynor in litt. 1995). The species is also at risk from the accidental introduction of alien species, particularly brown tree snake Boiga irregularis which has caused the extinction of many bird species on Guam (to USA) (Engbring et al. 1990).
Conservation Actions Underway
None is known.
Conservation Actions Proposed
Obtain a new population estimate and carry out regular monitoring to determine trends. Educate local people about the effects of dry-season fires on the species. Limit the use of fire in the dry season. Take measures to prevent the introduction of B. irregularis to Yap.
13 cm. Small dark passerine. Mostly olive-green with orange-yellow bill and legs. White eye-ring emphasized by black lores. Similar spp. Plain White-eye Z. hypolais smaller, paler, with less prominent eye-ring. Female and juvenile Micronesian Honeyeater Myzomela rubratra lack greenish tone and eye-ring. Voice Call a grating cheee. Song comprises lively whistled phrases such as fiddle-EE-feedle-DEE repeated monotonously. Hints Moves about in small parties, often in forest edge.
Text account compilers
Shutes, S., Mahood, S., Derhé, M., Stattersfield, A., Westrip, J., Wheatley, H., O'Brien, A.
Contributors
Raynor, B., Pratt, H.
Recommended citation
BirdLife International (2024) Species factsheet: Yap Olive White-eye Zosterops oleagineus. Downloaded from
https://datazone.birdlife.org/species/factsheet/yap-olive-white-eye-zosterops-oleagineus on 25/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 25/12/2024.