Sri Lanka Bay-owl Phodilus assimilis


Justification of Red List Category
This species has a very 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). The population trend appears to be stable, and hence the species does not 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.

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).

Trend justification
The population is suspected to be stable in the absence of evidence for any declines or substantial threats.

Distribution and population

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
Butchart, S., Ekstrom, J., Martin, R, Symes, A. & Taylor, J.

Praveen, J.

Recommended citation
BirdLife International (2023) Species factsheet: Phodilus assimilis. Downloaded from on 26/03/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 26/03/2023.