Data Zone
Justification of Red List category
Although this species has a small range, it is believed to occur at high densities within it and to have a relatively large population size. Moreover, despite some evidence of habitat loss and degradation, N. forbesi appears to be tolerant of these habitat modifications, and there is no indication that it is currently declining. For these reasons it is listed as Least Concern.
Population justification
The population size of this species has not previously been quantified, although it is described as fairly common (Coates and Bishop 1997; Eaton et al. 2016, 2021). Within this species' range, c.3,000 km2 of forest remains (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein). Densities of congeners range widely. Based on territory size data, Jakosalem et al. (2013) thought N. rumseyi could occur at densities of up to 20 mature individuals/km2, but for the similarly sized N. boobook, Olsen et al. (2011) found territory sizes up to 10 times bigger. It is likely that N. forbesi occurs at densities closer to the former, with reports of four pairs recorded from a single point, including two within 100 m of one another in 2022 (J. Eaton in litt. 2023). Assuming an approximate density of 8-20 mature individuals/km2, and that 50-80% of suitable habitat is occupied, the population is inferred to number 12,000-48,000 mature individuals.
Trend justification
Data on population trends for this species are lacking. Although forest cover loss is ongoing (Global Forest Watch 2022, based on data from Hansen et al. [2013] and methods disclosed therein) at a rate of c.5% over the past three generations (15.6 years: 2006-2022), most losses have been along roads, and this species is noted as being very tolerant of degraded forest, even that with cleared undergrowth (J. Eaton in litt. 2023). In the absence of other threats, the population is suspected to be stable.
Ninox forbesi is confined to the Banda Sea Islands Endemic Bird Area, Indonesia, where it occurs in the Tanimbar Islands.
This species inhabits primary and secondary forest in the lowlands (Eaton et al. 2021, Haryoko et al. 2021).
Habitat loss and degradation is the key threat to this species but this appears to be occurring at a rate too slow to cause declines in this degradation-tolerant species.
Conservation Actions Underway
No targeted conservation action is known for this species, although some of its habitat is protected.
Conservation Actions Proposed
Monitor populations and habitat trends on occupied islands. Conduct ecological studies to improve understanding of its precise habitat requirements, tolerance of secondary habitats and response to fragmentation. As a precaution, protect significant areas of suitable forest, in both strictly protected areas and community-led multiple use areas.
Text account compilers
Berryman, A.
Contributors
Butchart, S., Eaton, J., Ekstrom, J., Symes, A. & Taylor, J.
Recommended citation
BirdLife International (2024) Species factsheet: Tanimbar Boobook Ninox forbesi. Downloaded from
https://datazone.birdlife.org/species/factsheet/tanimbar-boobook-ninox-forbesi on 26/12/2024.
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 26/12/2024.