Phylloscopus amoenus 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Sylviidae

Scientific Name: Phylloscopus amoenus
Species Authority: (Hartert, 1929)
Common Name(s):
English Sombre Leaf-warbler, Kolombangara Leaf Warbler, Kulambangra Warbler, Sombre Leaf-Warbler
Taxonomic Notes:

Identification information: 11 cm. Small, stout, dumpy warbler. Heavy bill and long, stout legs are dark horn. Long, fine supercilium contrasts with dark forehead, fading into dreary olive upperparts with faint wing-bar. Underparts paler and brighter with obscure streaks. Similar spp. Island Leaf-warbler P. poliocephalus slighter with longer tail, brighter supercilium, greyer head with slight coronal stripe and plain yellow underparts. Voice Jumble of three to six high-pitched notes, shorter and sharper than P. poliocephalus and metallic tzik call. Hints Listen in the highest, mossy forest, where it forages in pairs, usually on moss and epiphyte-laden branches.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D1+2 ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Symes, A. & Butchart, S.
Contributor(s): Dutson, G., Iles, M. & Filardi, C.
Facilitator/Compiler(s): Derhé, M., Dutson, G., Ekstrom, J., Mahood, S., Pilgrim, J., Stattersfield, A.
This rather inconspicuous warbler is listed as Vulnerable on account of its very small range and population. 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)
2006 Vulnerable (VU)
2004 Vulnerable (VU)
2000 Vulnerable (VU)
1996 Vulnerable (VU)
1994 Vulnerable (VU)
1988 Threatened (T)

Geographic Range [top]

Range Description: Phylloscopus amoenus is endemic to the extinct volcano of Kolombangara, Solomon Islands, where it has been recorded above c.1,200 m and is presumed to occur to the summit at 1,740 m, at least on the Northeastern side (C. Filardi in litt. 2012). Its total range is therefore 21 km2, although much of this is unsuitable, being open forest on the inner slopes of the volcanic caldera. No more than two pairs have been recorded on any one visit, but it is estimated that the population could number 1,000-2,000 individuals. At the highest elevations on Kolombangara this bird appears to be the second most abundant passerine, behind Hermit White-eye Zosterops murphyi, with loose groups of 6-8 individuals encountered at times (C. Filardi in litt. 2012). There is no evidence of any long-term population changes (Buckingham et al. 1995, G. Dutson pers. obs. 1998, M. Iles verbally 1998, Hornbuckle 1999a).

Countries occurrence:
Solomon Islands
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 38
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): 1200
Upper elevation limit (metres): 1740
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population is estimated to number 700-1300 individuals, roughly equating to 470-870 mature individuals.

Trend Justification:  There is no evidence of any long-term population changes, thus the species is suspected to be stable.
Current Population Trend: Stable
Additional data:
Number of mature individuals: 470-870 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 inhabits mossy forest and has not been recorded from the large areas of open forest and scrub growing on landslide-damaged areas of the very steep crater. Singles and pairs forage low in the stunted forest, sometimes on moss-covered tree-trunks and on the ground; often in mixed species foraging flocks. Its nest is unknown (Buckingham et al. 1995, G. Dutson pers. obs. 1998, M. Iles verbally 1998).

Systems: Terrestrial
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 3.6
Movement patterns: Not a Migrant

Threats [top]

Major Threat(s): Although the montane forest is under no threat from forestry, it is often damaged by landslides so that the (small) population can be expected to fluctuate with habitat availability. It may be threatened by introduced mammalian predators such as feral pigs and rats which have been recorded from montane forest on Kolombangara (M. Iles verbally 1998). The species does not seem to descend to elevations lower than 1,400 m and so habitat may be very limited (C. Filardi in litt. 2012). Climate change may further narrow the species's range.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
The montane forest has been declared a forest reserve by the company which has logging rights to most of the island (M. Iles verbally 1998). The entire island above 400 m elevation is now under strict protection for biodiversity values by a partnership between the forestry company, KFPL, and a legally registered customary landholder organization, the Kolombangara Island Biodiversity Conservation Association (KIBCA). The area is slated to be recognized in the new national Protected Areas Act when regulations are fully gazetted for the act.

Conservation Actions Proposed
Establish a more accurate population estimate. Compare population densities in forests on inner and outer slopes of caldera. Map and measure the area of different forest-types. Monitor numbers in the most accessible areas. Investigate potential impacts of climate change on the species's range. Develop reforestation and habitat recovery actions for high elevation habitat. Investigate the occurrence of and threats posed by introduced predators. If found to be appropriate, begin control measures against introduced mammals.

Citation: BirdLife International. 2012. Phylloscopus amoenus. The IUCN Red List of Threatened Species 2012: e.T22715412A39553349. . Downloaded on 01 December 2015.
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