Zosterops samoensis 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Zosteropidae

Scientific Name: Zosterops samoensis
Species Authority: Murphy & Mathews, 1929
Common Name(s):
English Samoan White-eye
Taxonomic Notes:
Identification information: 10 cm. Small, warbler-like bird. Olive-green above, dingy white below with yellow tinge to throat and conspicuous, completely white eye-ring. Pale iris. Voice Undescribed. Hints Moves about in small flocks.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Symes, A. & Butchart, S.
Contributor(s): Ericsson, S. & Hobcroft, D.
Facilitator/Compiler(s): Derhé, M., Mahood, S., O'Brien, A., Shutes, S., Stattersfield, A.
This species is poorly known and its status is difficult to assess, not least owing to the paucity of information. However, it is restricted to one island only where it occupies a very small area of forest and consequently it qualifies as Vulnerable. If further research shows that its population is declining or fluctuates with natural events, it may be uplisted to a higher category of threat.

Previously published Red List assessments:
2008 Vulnerable (VU)
2004 Vulnerable (VU)
2000 Vulnerable (VU)
1996 Vulnerable (VU)
1994 Vulnerable (VU)
1988 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description: Zosterops samoensis is endemic to Savai`i, Samoa. In 1987 and again in 1991, it was found to be not uncommon (even though the latter survey was after the severe cyclone "Ofa") (Bellingham and Davis 1988, S. Ericsson in litt. 1994). However, though it is thought to be moderately common in suitable habitat (D. Hobcroft 2007), groups of birds are constantly moving (at least outside the breeding season) and thus numbers could be overestimated; in 1999, it appeared uncommon (Beichle in prep.).

Countries occurrence:
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 520
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 1
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Lower elevation limit (metres): 780
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population is thought to number fewer than 2,500 individuals, and so is placed in the band 1,000-2,499 individuals. This equates to 667-1,666 mature individuals, rounded here to 600-1,700 mature individuals.

Trend Justification:  There are no new data on population trends; however, the population is assumed to be stable.
Current Population Trend: Stable
Additional data:
Number of mature individuals: 600-1700 Continuing decline of mature individuals: No
Extreme fluctuations: No Population severely fragmented: No
No. of subpopulations: 1 Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: Yes
No. of individuals in largest subpopulation: 100

Habitat and Ecology [top]

Habitat and Ecology: It occurs in the highlands mainly above 900 m where it has been recorded in flocks of 15-20 birds in the canopy of prime upland forests, but has been recorded as low as 780 m, and also in open scrub-like alpine habitat (Bellingham and Davis 1988, S. Ericsson in litt. 1994). It requires a big territory as food-blossoms are very limited and because of competition with other nectarivorous birds (e.g. honeyeaters) (Beichle in prep.).

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 3.5
Movement patterns: Not a Migrant

Threats [top]

Major Threat(s): Slash-and-burn cultivation threatens remaining areas of upland forest, as farmers use forestry roads from heavily logged lowland forests to gain access to formerly inaccessible land (Bellingham and Davis 1988). Black rat Rattus rattus may also pose a threat to the species (D. Hobcroft in litt. 2012).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Mt Silisili Park, a unique area of montane cloud-forest in central Savai`i, is a refuge for the species (Beichle and Maelzer 1985).

Conservation Actions Proposed
Research its population size, distribution and ecology (Bellingham and Davis 1988). Ensure the protection of Mt Silisili Park.

Citation: BirdLife International. 2012. Zosterops samoensis. The IUCN Red List of Threatened Species 2012: e.T22714258A39635315. . Downloaded on 30 November 2015.
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