Data Zone
Justification of Red List category
This species has a large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence under 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). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (under 10,000 mature individuals with a continuing decline estimated to be over 10% in ten years or three generations, or with a specified population structure). 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 (over 30% decline over ten years or three generations). For these reasons the species is evaluated as Least Concern.
Population justification
The global population size has not been quantified, but the species is considered to be very rare throughout most of its range (del Hoyo et al. 1999). This species is considered to have a medium dependency on forest habitat, and tree cover is estimated to have declined by 5% within its mapped range over the past three generations (Global Forest Watch 2022, using Hansen et al. [2013] data and methods disclosed therein). Therefore, as a precautionary measure, it is tentatively suspected that this loss of cover may have led to a decline of between 1-19% in the species' population size over the same time frame.
Trend justification
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P. assimilis (incorporating ripleyi) is found in southern India and Sri Lanka (Rasmussen and Anderton 2005). In the Western Ghats it is distributed from Sirsi in the north south to Kalakkad-Mundanthurai Tiger Reserve (KMTR) (J. Praveen in litt. 2013).
Occurs in humid evergreen forest, mixed forest, mangrove and cut-over forest, where it is strictly nocturnal (Rasmussen and Anderton 2005). Occurs from the lowlands to 1,200 m (König and Weick 2008).
23-27 cm. Chunky, short-winged and short-tailed strictly nocturnal owl with a heart-shaped facial disc. Dark, chestnut toned upperparts, well spotted and with golden-ochre scapulars. Pale buff below with sparse black spotting. Similar spp. Oriental Bay Owl P. badius (which the present species was previously included) is paler and brighter rufous above with the tail at most lightly barrred and appearing more uniform chestnut. Voice. Loud, eerie, complex series of slow quavering multi-element whistles. Oriental Bay Owl P. badius has a simpler, faster series of quavering, rising notes.
Text account compilers
Rutherford, C.A.
Contributors
Praveen, J.
Recommended citation
BirdLife International (2024) Species factsheet: Sri Lanka Bay-owl Phodilus assimilis. Downloaded from
https://datazone.birdlife.org/species/factsheet/sri-lanka-bay-owl-phodilus-assimilis on 23/12/2024.
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 23/12/2024.