Data Zone
Justification of Red List category
This inconspicuous and extremely poorly known forest owl is listed as Near Threatened due to a small range that is undergoing continuous habitat loss and degradation due to logging and infrastructure development. Apparent threats do not suggest that the species occurs in only few locations and the population is not severely fragmented, hence does not meet threatened thresholds.
Population justification
Population size unknown, with no records between the collection of the type specimen in 1938 (White and Bruce 1986), and the first field observation in October 1991 (Stones et al. 1995). It has since been found by several visitors to the island (Rheindt 2010, Bruce et al. 2020, eBird 2024), and Eaton et al. (2016) considered it a ‘scarce’ species. As a nocturnal species it is assumed to have very low detectability, and likely to be overlooked. Taliabu is not a very small island (3,000 km2), hence the population size of this species, even if only a small percentage of the island is occupied, is unlikely to be very small given the species utilises forest edge as well as interior forests. If the species is found on other islands in the Sula archipelago, its population size will be even greater.
Trend justification
A remote sensing analysis in this species’ range over the past three generations (2007-2022) indicates a decline in tree cover of 21.9 kha, equivalent to a 7.9% decrease in tree cover (Global Forest Watch (2024) based on data from Hansen et al. (2013) and methods therein). This decline in tree cover is suspected to be negatively impacting the population, given the species' presumed dependence on forest habitat. However, records show that this species has been found in dense secondary bamboo thickets at 90 m, heavily logged forest with no understory at 900 m, as well as selectively logged lowland forest (Rheindt, 2010, Davidson et al. 1995). It has also been observed in coconut plantations and occasionally in close proximity to human habitation (Bruce et al. 2020). This indicates both a broad elevational range and a tolerance for disturbed habitat.
Estimating the population trend of this species is challenging due to an absence of information. However it is concluded, somewhat precautionarily, that rates of forest cover loss are having a proportional impact on this species' population size. Accordingly, the species is suspected to have declined by 1-15% over the past three generations, with the same rate suspected to occur in the future, with no evidence that Taliabu's lowland forests are being adequately safeguarded from future clearance.
This species is endemic to the Sula Islands, Maluku, Indonesia, where it is known from just one specimen (collected in 1938) and a handful of subsequent sight records, all from the largest island in the group, Taliabu (Davidson et al. 1991, Rheindt 2010, eBird 2024). It is possible that future surveys will reveal its presence on the neighbouring island of Mangole and perhaps Sanana (Rheindt 2010).
Little is known of its ecology. The only specimen was collected in lowland forest, however, recent sightings have been made in heavily logged forest and dense secondary bamboo thickets suggesting that it can tolerance habitat degradation (Rheindt 2010).
Large-scale logging of lowland forest has taken place, and some areas have been clear-felled for industrial timber production. Most of Taliabu's lowland forest, below 800 m, is designated as a logging concession. Selective logging has already produced a mosaic of different-aged forest stands, with few, if any, extensive tracts of primary lowland forest remaining, except perhaps in the central south-west of the island (Davidson et al. 1995). Infrastructure development on Taliabu poses another threat by encroaching into natural habitats and furthering habitat loss and degradation (Pattimahu et al. 2017). The effects of habitat loss and degradation on this species remain largely unknown, but in combination the processes driving forest loss are thought to represent considerable threats.
Conservation and Research Actions Underway
Listed in CITES Appendix II. Present in Banggai and Sula Islands EBA (Bruce and Kirwan 2013). A strict nature reserve has been proposed for the island, but only c. 18% encompasses lowland forest, and it remains to be confirmed that this site is appropriate for the conservation of this rare owl.
Conservation and Research Actions Proposed
Conduct widespread searches for the species (including the neighbouring islands of Mangole and Sanana), questioning local people about its possible presence and clarifying its range, distribution, status and ecological requirements. Reassess its threat status and conservation needs, recommending further areas for protection where appropriate. Ensure effective management of any forthcoming protected area on Taliabu.
31-32 cm. Medium-sized, forest-dwelling owl. Female has dark brown upperparts with lines of small white spots. Dark and unbarred wings, secondaries with whitish tips, brown tail with three dark bars. Golden-brown underparts, spotted and vermiculated black. Black iris. Male presumably similar but undescribed. Similar spp. Brown Hawk-owl Ninox scutulata is smaller with yellow irides, streaked underparts and barred tail. Voice a hissing sound typical of the genus (Rheindt 2010).
Text account compilers
Chad, E.
Contributors
Rheindt, F., Robson, C., Eaton, J. & Westrip, J.R.S.
Recommended citation
BirdLife International (2024) Species factsheet: Taliabu Masked-owl Tyto nigrobrunnea. Downloaded from
https://datazone.birdlife.org/species/factsheet/taliabu-masked-owl-tyto-nigrobrunnea on 22/11/2024.
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 22/11/2024.