Justification of Red List Category
This enigmatic species is classified as Vulnerable on the basis of a small subpopulations on three island which are declining through habitat degradation. However, its total population size and habitat requirements are poorly known.
In a well-studied area at Tirotonga on Isabel, three nests were about 2 km apart (G. Dutson pers. obs. 1998, M. Hafe verbally 1998), which would extrapolate to an approximate total population of c.3,000 pairs, but it appears to be unusually common in this area (G. Dutson pers. obs. 1998). Elsewhere, there have been records only of singles or single pairs. It is plausible that the subpopulations on the three islands each number less than 1,000 mature individuals.
Forest loss and degradation are suspected to be causing this species to decline at a moderate rate.
Nesasio solomonensis is endemic to Bougainville in Papua New Guinea and Choiseul and Santa Isabel in the Solomon Islands. There are also possible reports from Buka. It is presumed to be a species of low population density as it is rarely seen and no more than one bird has been heard calling from any location. All records are from old-growth forest.
This large owl is the top predator along with Sanford's Fish-eagle Haliaeetus sanfordi and is reported to feed mostly on northern common cuscus Phalanger orientalis (Diamond 1975a, Webb 1992). Cuscus were introduced to these islands in prehistoric times; presumably the owl previously fed on the giant arboreal rats which are now very rare across their range (Flannery 1995). Its distribution may now mirror that of P. orientalis which is heavily hunted for food in some districts (Webb 1992). All records are from old-growth lowland and hill forest, usually in primary forest but also in adjacent secondary forest and forest edge to at least 2,000 m (Gardner 1987, Webb 1992, G. Dutson pers. obs. 1998, Dutson 2011). Three nests on Isabel were on ephiphyte-covered branches of huge fig trees, one was in primary forest, the other two in forest edge close to many gardens (Webb in litt. 1996, G. Dutson pers. obs. 1998).
This species is threatened by large-scale logging and deforestation in the lowlands, which has increased in intensity in recent years, and most of the lowlands of Choiseul and Santa Isabel have been logged or have logging concessions (Katovai et al. 2015). It may also be less common in areas where rural communities over-hunt prey species P. orientalis (Dutson 2011).
Conservation Actions Underway
CITES Appendix II. No conservation measures known.
38 cm. Massive forest owl. Golden eyes framed by prominent creamy eyebrows, otherwise warm brown. Streaked dark underparts and barred dark upperparts. Similar spp. Solomons Islands Hawk-owl Ninox jacquinoti is much smaller (25-30 cm) with plainer facial mask, dark eyes and faintly patterned underparts. Voice Similar to clear human cry, increasing in volume and tone, given as series at 10 second intervals. Hints Rarely seen unless a local guide knows of regular roost or nest-sites.
Text account compilers
Derhé, M., Dutson, G., Mahood, S., O'Brien, A., Stattersfield, A. & North, A.
Dutson, G., Hafe, M. & Webb, H.
BirdLife International (2022) Species factsheet: Nesasio solomonensis. Downloaded from http://www.birdlife.org on 09/12/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 09/12/2022.