Justification of Red List Category
This species is listed as Endangered because it has a very small range and correspondingly small population, both of which are undergoing a decline owing to habitat loss and degradation.
Extensive surveys have located 100 individuals and led to a global population estimate of 200-250 individuals. However, given the species's elusive nature and its ability to remain undiscovered for so long the true population size is likely to be somewhat higher. Therefore, it is probably best placed in the band 250-999 individuals. This equates to 167-666 mature individuals, rounded to 150-700 mature individuals here.
The species appears to be intolerant of habitat loss and severe fragmentation, and so is suspected to be declining as the very few remaining unprotected areas of forest are slowly lost. The likely rate of population decline has not been estimated.
Otus thilohoffmanni is endemic to the wet zone of Sri Lanka, where it is known only from Kitugala, Sinharaja, Morapitiya-Runakanda, Kanneliya and Eratna-Gilimale, despite investigation of c.75% of suitable habitat (Warakagoda and Rasmussen 2004, U. Sirivardana in litt. 2006). It escaped detection until 1995 due to its unobtrusive and rather ventriloquial call. Fewer than 100 individuals have now been located in the five known sites (U. Sirivardana in litt. 2006), but it is likely that others remain undetected (Warakagoda and Rasmussen 2004), and it may well occur at additional sites in the wet zone rainforests. On present knowledge the global population is believed to number c.200-250 individuals (Warakagoda 2006), although given its elusive nature the true figure may be somewhat higher.
It occurs in larger areas of lowland rainforest, at 30-530 m altitude (Warakagoda and Rasmussen 2004). It appears to be generally rare, but locally common (Warakagoda and Rasmussen 2004), and pairs occupy large territories (U. Sirivardana in litt. 2006). All locations where the bird has been found so far have been disturbed areas with tall, dense secondary growth (Warakagoda and Rasmussen 2004). For the two hours after dark, it hunts for prey in the undergrowth, later foraging higher; between the undergrowth and subcanopy (Warakagoda and Rasmussen 2004). During the day it roosts 1-2.5 m above the ground, sometimes in pairs within a territory and it will adopt a cryptic posture mimicking wood when threatened (Warakagoda and Rasmussen 2004, Warakagoda 2006). The breeding behaviour of this species is not yet known.
It has not been found in forest patches smaller than 8.2 km2 in extent, indicating that it is sensitive to habitat loss and fragmentation, which has been severe in Sri Lanka (Warakagoda and Rasmussen 2004). Habitat loss is still continuing owing to pressure from settlement, encroachment on protected forests from subsistence logging and small-scale mining operations.
Conservation Actions Underway
All five known sites are protected as Forest Reserves or Proposed Reserves, administered by the Forestry Department (Warakagoda and Rasmussen 2004).
16.5 cm. A small, short-tailed scops-owl, lacking true ear-tufts. Quite uniformly rufescent, paler below, with small dark markings all over. Central belly and undertail coverts paler and unspotted. Weakly defined facial disk, and yellow to orange irides with a black outer ring. Iris more yellow in female. Tarsi feathered for less than half their length. Similar spp. In range, only the rufous morph of the Sri Lankan race of Oriental Scops-owl Otus sunia leggei, which is slightly larger, and has obvious ear-tufts, tarsi feathered to base of toes, and obvious whitish spots on scapulars. Voice Female gives a short, piping, tremulous pU'U'u, rising and falling in pitch. Male gives a lower pitched, shorter, less tremulous version. Vocalisations most common in the hours just after dusk and just before dawn.
Text account compilers
Bird, J., Pilgrim, J. & Taylor, J.
Kaluthota, C., Sirivardana, U. & de Silva Wijeyeratne, G.
BirdLife International (2021) Species factsheet: Otus thilohoffmanni. Downloaded from http://www.birdlife.org on 27/10/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 27/10/2021.