Data Zone
Justification of Red List category
This species is assessed as Near Threatened because it is suspected to have a small population and range, which are inferred to be declining due to ongoing forest loss and degradation.
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.
Phylloscopus maforensis is found only in forest on the island of Numfor in Geelvink Bay, Indonesia (Pratt and Beehler 2015).
This species inhabits primary and secondary forest at all elevations across the island (Beehler and Pratt 2016).
The only identified threat for this species is forest loss. 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 a forest dependent species, it is suspected that this is causing population reductions.
Conservation Actions Underway
No protected area currently exists on Numfor, although a reserve has been proposed (Diamond 1986).
Conservation Actions Proposed
Conduct surveys to get better population size and trend estimates. Support plans to establish a nature reserve on Numfor.
Text account compilers
Berryman, A.
Contributors
Bishop, K.D., Butchart, S., Dutson, G., Ekstrom, J. & Westrip, J.R.S.
Recommended citation
BirdLife International (2024) Species factsheet: Numfor Leaf-warbler Phylloscopus maforensis. Downloaded from
https://datazone.birdlife.org/species/factsheet/numfor-leaf-warbler-phylloscopus-maforensis on 24/12/2024.
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 24/12/2024.