NT
Nicobar Scops-owl Otus alius



Justification

Justification of Red List Category
This species was until recently classified as Data Deficient, because it was known from very few records and there was insufficient evidence to estimate the current range size or the population size and trend. By now, knowledge about the species's distribution and population size has increased: While the population on Great Nicobar is likely to exceed 1,000 mature individuals, the species also occurs on Nancowry Island and perhaps on other islands of the southern Nicobar group. However, there remains considerable uncertainty over the rough population estimate due to a lack of information over the degree to which the species is habitat restricted. The species is therefore listed as Near Threatened, as it has a small population size which is inferred to be undergoing a continuing decline due to habitat clearance and degradation.

Population justification
The species is described as common, particularly on Great Nicobar (P. Singh per Rasmussen and Anderton 2012, S. Dalvi to P. Rasmussen per P. Rasmussen in litt. 2016). Using high population density estimates for congeners, and assuming that only a proportion of its range is occupied, would give a population size of 3,200 mature individuals for Great Nicobar. The species has been found on Teressa Island and may occur on further islands in the Nicobar group, although some of the more northerly islands have been surveyed and the species has not been found. Therefore, the global population size may be best placed in the range of 2,500-9,999 mature individuals.

Trend justification
The population is potentially declining as a consequence of slow rates of habitat loss (per Tracewski et al. 2016) as well as anthropogenic impacts like hunting and snaring or the use of pesticides.

Distribution and population

The species is endemic to the Nicobar Islands in the Bay of Bengal, India. It is known from two specimens collected at Campbell Bay on Great Nicobar (BirdLife International 2001), and one bird trapped and photographed in March 2003 on Nancowry Island (Arora 2015). The species may occur on other islands of the southern Nicobar group, particularly Little Nicobar, and is perhaps restricted in range on Great Nicobar. Recently, its call has become better known, and it has been reported that the species was particularly common on Great Nicobar (P. Singh per Rasmussen and Anderton 2012), and remains so common that people may no longer look for it as a rare/uncommon species to see (S. Dalvi to P. Rasmussen per P. Rasmussen in litt. 2016).

Ecology

Very little is known about the species' ecology. The paratype was found in coastal forest (presumably at sea-level) c.1 km from the shore. It is thought likely to be a sedentary resident. It breeds presumably in March-April (Rahmani 2012). Of the two birds collected, one individual was said to have eaten a spider and beetle, and the other had consumed a gecko (König and Weick 2008).

Threats

Specific threats are unknown. However, the coastal forest on Great Nicobar is under threat from a range of processes, particularly due to agriculture (plantations of coconut, banana, cashew and rice) and settlement expansions, as well as road development projects. The Tsunami of 26th December 2004 may also have impacted the species, as not only did it destroy large areas of potential habitat, but it has also exacerbated the original threats to coastal forest, with the people displaced by the Tsunami subsequently clearing new areas to build houses and grow crops (K. Sivakumar in litt. 2005, S. Pande in litt. 2016). The use of pesticides and insecticides may be impacting the species's food sources and there may be some low-level direct mortality from human activities as airguns are common and bird trapping does occur (S. Pande in litt. 2016), though the extent to which these practices affect the species is uncertain. The proposal to develop Great Nicobar as a free-trade port, a potentially major threat, appears unlikely to be realised in the near future (K. Sivakumar in litt. 2005).

Conservation actions

Conservation Actions Underway
CITES Appendix II. The whole of Great Nicobar is a Biosphere Reserve, within which there are two National Parks, Campbell Bay and Galatea. Furthermore, designation of most of the Nicobar islands as tribal areas legally prohibits commercial exploitation of natural resources and settlement or ownership of land by non-tribals.

Conservation Actions Proposed
Conduct surveys on Great Nicobar (and then Little Nicobar) using tape-playback to determine presence/absence, and where possible estimate densities of the species in various habitats across the islands. Carry out research into the impacts of potential threats to the species.

Identification

c. 20 cm. Small scops-owl with a warm brown colouration with fine dark bars; facial disc paler, lightly barred; small ear-tufts; iris conjecturally yellow; tarsus unfeathered. Voice Male unknown, female gives repeated melancholic moan on rising scale. Similar spp. Easily distinguishable from all other Asian species of Otus by its finely barred plumage, large claws and larger body size.

Acknowledgements

Text account compilers
Westrip, J., Wheatley, H., Davidson, P., Martin, R., Benstead, P., Peet, N., Hermes, C., Symes, A., Taylor, J., Tobias, J.

Contributors
Pande, S., Dalvi, S., Sivakumar, K., Rasmussen, P.


Recommended citation
BirdLife International (2019) Species factsheet: Otus alius. Downloaded from http://www.birdlife.org on 22/04/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 22/04/2019.