This discussion was first published as part of the 2013 Red List update, but remains open for comment to enable reassessment in 2015.
Taliabu Masked-owl Tyto nigrobrunnea is restricted to the Sula Islands, Maluku, Indonesia. It is currently listed as Endangered under criteria B1ab(ii,iii,v); C2a(ii), on the basis that it has a very small range, and presumably a very small population, both of which were thought to be in decline owing to extensive logging.
This species was previously known from just one specimen collected in 1938 in lowland forest on the largest island in the group, Taliabu (Davidson et al. 1991, Rheindt 2010). However, recent information states that it appears to occur within a broad elevational range, it is well-known to villagers at Binadesa, and recent sightings have been made in heavily logged forest and dense secondary bamboo thickets, suggesting that it can tolerate substantial habitat degradation (Rheindt 2010). Unlike the other islands in the region, there is no open-country congener on Taliabu, which may have allowed it to adapt to disturbed habitats (Rheindt 2010). Furthermore, it is possible that future surveys will reveal its presence on the neighbouring island of Mangole and perhaps Sanana (Rheindt 2010). As a result, it has been suggested that this species may not warrant threatened status (F. Rheindt in litt. 2012). Nevertheless, despite the lack of information on its population size, the paucity of records (even taking into account its inconspicuous nature and the fact that it could easily be overlooked) indicate that it could still be very scarce. The population is estimated to number 250-999 mature individuals based on an assessment of known records, descriptions of abundance and range size.
If this evidence is confirmed, and the area and extent of habitat and number of mature individuals of this species is not declining, this species would no longer qualify as Endangered under criterion B or C of the IUCN Red List. If the population estimate of <1,000 mature individuals is confirmed, this species would warrant downlisting to Vulnerable under criterion D1. If the population approaches 1,000 mature individuals, it would warrant downlisting to Near Threatened.
Further information is required on this species’s distribution, population size and trends, and comments on its proposed downlisting are welcome. Input is invited on whether habitat quality for this species is effectively in decline and whether this is likely to be driving an on-going population decline overall.
Davidson, P., Stones, A., Lucking, R., Bean, N., van Balen, B., Raharjaningtrah, W. and Banjaransari, H. (1991) University of East Anglia Taliabu expedition 1991.
Rheindt, F. E. (2010) New biogeographic records for the avifauna of Taliabu (Sula Islands, Indonesia), with preliminary documentation of two previously undiscovered taxa. Bulletin of the British Ornithologists’ Club 130(1): 33-51.