Least Boobook Ninox sumbaensis


Justification of Red List Category
This poorly known species is thought to occupy only a very small area which has almost certainly declined through forest clearance within its range. Therefore, it is now listed as Endangered.

Population justification
This species is very poorly known but it is thought to be uncommon given that it escaped detection for many years and there are few records available. It is placed in the band 10,000-19,999 mature individuals, equating to 15,000-29,999 individuals in total, rounded here to 15,000-30,000 individuals. This preliminary population estimate requires clarification.

Trend justification
The population is inferred to be in decline owing to on-going habitat destruction.

Distribution and population

Ninox sumbaensis was formally described only recently, although the taxon has been known to ornithologists since the late 1980s (Olsen et al. 2002). It is currently very poorly known and has only been recorded from three localities on Sumba, Indonesia (Linsley et al. 1998, Olsen et al. 2002, Benstead and Benstead in prep.). Tracewski et al. (2016) estimated the maximum Area of Occupancy (calculated as the remaining tree area within the species’s range) to be c.159 km2, rounded here to 160 km2.


It appears to be limited to small patches of primary, disturbed primary, secondary and degraded forest at 600-950 m on Sumba. Young offspring have been observed in November (Olsen et al. 2009).


It is undoubtedly at some risk from on-going habitat loss owing to logging and agricultural expansion.

Conservation actions

Conservation Actions Underway
None are known.

Conservation Actions Proposed
Survey work is required to ascertain the distribution and status of this poorly known owl. As a precaution, protect significant areas of suitable forest, in both strictly protected areas and community-led multiple use areas.


Text account compilers
Taylor, J., Khwaja, N., Westrip, J., Bird, J., Symes, A., Benstead, P.

Crosby, M., Benstead, P.

Recommended citation
BirdLife International (2022) Species factsheet: Ninox sumbaensis. Downloaded from http://www.birdlife.org on 23/05/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/05/2022.