Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
The global population size has not been quantified, but the species is reported to be rare to very rare throughout most of its range (del Hoyo et al. 1999), while national population sizes have been estimated at c.100-10,000 breeding pairs in China and < c.100 breeding pairs in Taiwan (Brazil 2009).
This species is suspected to be in decline owing to the continuing destruction and degradation of its habitat and use, in Australia, of rodenticides to control rats (del Hoyo et al. 1999).
Text account compilers
Ekstrom, J., Butchart, S.
BirdLife International (2020) Species factsheet: Tyto longimembris. Downloaded from http://www.birdlife.org on 08/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 08/08/2020.