Numfor Leaf-warbler (Phylloscopus maforensis)

Numfor Leaf-warbler Phylloscopus maforensis

Current view: Data table and detailed info

Taxonomy

Taxonomic note

Phylloscopus poliocephalus and P. makirensis (Sibley & Monroe [1990, 1993]) have been lumped and subsequently split into P. poliocephalus, P. misoriensis and P. maforensis following del Hoyo and Collar (2016).

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red List criteria met and history

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	-

Red List history

Year	Category	Criteria
2022	Near Threatened	B1b(ii,iii)+2b(ii,iii); C2a(ii)
2016	Vulnerable	C2a(ii)
2012	Not Recognised
2008	Not Recognised
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

Species attributes

Migratory status	not a migrant	Forest dependency	medium
Land-mass type		Average mass	-

Range

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	460 km²
Area of Occupancy (breeding/resident)	460 km²
Severely fragmented?	no	-

Population

	Estimate	Data quality	Derivation	Year of estimate
Population size	2500-9999 mature individuals	poor	suspected	2016
Population trend	decreasing	-	suspected	2020-2030
Rate of change over the past 10 years/3 generations (longer of the two periods)	5-10%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	5-15%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	5-15%	-	-	-
Generation length	2 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: The population size has not been directly estimated, but the species is described as uncommon (G. Dutson in litt. 2016, eBird 2021). Based on population density estimates of congeners, and assuming only a proportion of habitat is occupied, the population size is suspected to fall in the range of 2,500-9,999 mature individuals. However, this requires confirmation.

Trend justification: Remote sensing data (Global Forest Watch [2021], using data from Hansen et al. [2013] and methods disclosed therein) indicate that forest loss in this species' range was c.5% over the past decade and may accelerate to 5-15% over the next. As this is a forest dependent species, it is suspected that the rate of population decline will be broadly similar to the reduction in forest cover.

Country/territory distribution

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Indonesia	extant	native	yes

Important Bird and Biodiversity Areas (IBA)

Country/Territory	IBA Name

Habitats & altitude

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude	0 - 180 m	Occasional altitudinal limits

Threats & impact

Threat (level 1)

Threat (level 2)

Impact and Stresses

Agriculture & aquaculture

Annual & perennial non-timber crops - Small-holder farming

Timing

Scope

Severity

Impact

Ongoing

Minority (<50%)

Slow, Significant Declines

Low Impact: 5

Stresses
Ecosystem degradation, Ecosystem conversion

Biological resource use

Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest]