NT
Nicobar Bulbul Ixos nicobariensis



Justification

Justification of Red List Category
This species has a small population which is suspected to be declining as a result of clearance and degradation of forests for plantation agriculture and infrastructure projects. More rigorous application of the critieria means this species has been downlisted to Near Threatened as the population declines are suspected based on habitat loss and degradation, and are not currently supported by quantitative data.

Population justification
The population is estimated to number 2,500-9,999 individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.

Trend justification
Habitat change continues within the range, and although the impact on populations is unclear, it is suspected that declines are likely to be occurring.

Distribution and population

This species is endemic to the Nancowry island group, part of the Nicobar Islands in the Bay of Bengal, India. It occurs on Camorta, Trinkat, Nancowry, Katchall, Teressa, Bompoka and Tillanchong. It is declining locally, although it remains common in some areas of Katchall.

Ecology

It is a sedentary resident, inhabiting primary and secondary forests and forest edge. It also occurs in gardens, coconut and rubber plantations, around human habitation and occasionally grasslands, suggesting it is tolerant of some habitat degradation. It is usually found singly or in pairs, but one recent observation concerned a loose flock of over 100 individuals. Its breeding behaviour has not been described but adults have been seen to feed nestlings and fledglings from late February to mid April (A. P. Zaibin in litt. 2012)

Threats

Clearance and conversion of forests for plantation agriculture (particularly rubber, coconut and cashew cultivation) and infrastructure development (including roads, human settlements and defence establishments) are the most serious long-term threats. Over 6 km2 of forest have been lost on Katchall to rubber plantations. Competition with the introduced Red-whiskered Bulbul Pycnonotus jocosus may have contributed to its decline, but as yet there is no evidence to confirm this. There is no evidence that it was significantly affected by the 2004 tsunami (R. Sankaran in litt. 2008).

Conservation actions

Conservation Actions Underway
The whole of Tillanchong island is uninhabited and protected as a wildlife sanctuary. All the islands in the Nancowry group are designated tribal reserves, which legally prohibits commercial exploitation of natural resources, along with settlement or ownership of land by non-tribal people.

Conservation Actions Proposed
Conduct regular surveys to monitor population size and trends on each island of occurrence. Conduct research into its ecological requirements, and its interactions with Red-whiskered Bulbul. Support proposals to designate the entire Nancowry island group a Biosphere Reserve and establish strict protected areas on the islands of Camorta and Katchall. Control the population of Red-whiskered Bulbul if competition with that species is proven to constitute a threat.

Identification

20 cm. Non-descript bulbul. Sooty-brown crown and whitish to pale yellow underparts. Similar spp. Juvenile Red-whiskered Bulbul Pycnonotus jocosus has short crest, white ear-coverts and underparts, blackish moustachial line and lateral breast-bar, dull reddish undertail-coverts and white-tipped outer tail feathers. Voice Chattering notes, recalling Black Bulbul H. leucocephalus.

Acknowledgements

Text account compilers
Benstead, P., Davidson, P., Gilroy, J., Khwaja, N., Mahood, S., Peet, N., Symes, A., Tobias, J., Westrip, J.

Contributors
Zaibin, A., Sivakumar, K., Sankaran, R., Davidar, P.


Recommended citation
BirdLife International (2020) Species factsheet: Ixos nicobariensis. Downloaded from http://www.birdlife.org on 08/04/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 08/04/2020.