Data Zone
Justification of Red List category
This species has a large range that spans much of South and South-East Asia, where it has adapted well to agricultural landscapes with sufficient areas to forage. It has a large population size thought to number 250,000-500,000 mature individuals and the population trend is likely increasing. It is therefore evaluated as Least Concern.
Population justification
Wetlands International (2002) estimated the population in South-East Asia and South Asia as, respectively, up to 10,000 and 25,000, although these data are now more than two decades out of date and it is evident from South Asia at least that these data likely represent a considerable underestimate. Numbers in South Asia apparently exceed 400,000 (K. S. G. Sundar in litt. 2024) and it is likely that numbers in South-East Asia have also historically been underestimated. The global population size of this species is therefore estimated at 400,000-600,000 birds. In line with other waterbird populations (e.g. Meininger et al. 1995) 20-35% of birds at at any one time are likely to be immature. Accordingly the number of mature individuals is estimated at 260,000-480,000, rounded here to 250,000-500,000.
Trend justification
In India, where a great majority of the global population probably resides, a recent analysis of citizen science data found an increase in reporting rate (SoIB 2023) while long-term monitoring of waterbirds in Kerala also recently reported considerable increases (Nameer et al. 2015, Praveen J in litt. 2024). These increases have been attributed to the species' ability to exploit farmland and the increasing irrigation canal network across South Asia (K. S. G. Sundar in litt. 2024). In South-East Asia, the overall population is probably also now increasing, in large part because of the protection of the Prek Toal colony in Cambodia (see Goes 2013) and a concurrent spread and increase in abundance in wetlands in neighbouring Thailand, and perhaps also southern Vietnam (eBird 2024). In Myanmar the species is apparently stable across its range in the country (sometimes with inter-annual variation) (Zöckler et al. 2014, C. Zöckler in litt. 2024). Locally, in parts of its range (especially in South-East Asia), disturbance, hunting and egg collecting may continue to cause local declines, but these threats either in isolation or when compounded are not thought to be acute or widespread enough to be affecting global trends.
Resident across virtually all of India and Sri Lanka, marginally also in south-east Pakistan. Occurs in the Himalayan foothills of Nepal and very locally Bhutan (where there are records from the upper reaches of the Manas River: eBird 2024), as well as Bangladesh. Occurs throughout suitable habitat in Myanmar. Status in China and Japan unclear, but treated here as a vagrant given paucity of recent records, but may be better considered a very rare non-breeding visitor. Occurs in central Thailand (particularly in wetlands around Bangkok north to Nakhon Sawan) with records increasingly further north in response to increasing populations. Vagrants have also reached the Philippines. Throughout wetlands of Cambodia and southern Viet Nam, but puzzlingly absent from Lao PDR, where remains known from only a single historical record (Duckworth et al. 1999, Timmins et al. 2024). Scattered records from northern Viet Nam, particularly from Xuan Thuy National Park, but here probably only a vagrant or very sporadic non-breeding visitor. Occurs regularly as far south as Phatthalung province, southern Thailand, but sporadic records stretch south into Peninsular Malaysia where it was once more regular than it is now. Vagrant to Singapore, where sporadic records (especially at Sungei Buloh Wetland Reserve). Range and abundance in Indonesia poorly known, but evidently still regular at least in south-east Sumatra and westernmost Java (around Jakarta).
It inhabits freshwater marshes, lakes, rivers, flooded grasslands, paddy fields, tidal creeks, intertidal mudflats, mangroves, saltmarshes and coastal lagoons, usually in coastal wetlands or extreme lowlands, but occasionally up to 950 m. In some areas, agricultural land may be an important habitat for the species (Sundar 2009, Sundar and Kittur 2013, G. Sundar in litt. 2024). It is largely sedentary throughout most of its range but tends to be nomadic in response to changing water levels and feeding conditions (Matheu et al. 2016).
Disturbance, hunting and egg collecting may continue to cause local declines, but these threats either in isolation or when compounded are not thought to be acute or widespread enough to be affecting global trends. Historically, these are likely to have been substantially more acute threats, particularly in South-East Asia.
Text account compilers
Berryman, A.
Contributors
Wang, Q., Mahood, S., Kumar Koli, V., Zöckler, S., Gopi Sundar, K.S., Pilgrim, J. & Praveen J
Recommended citation
BirdLife International (2024) Species factsheet: Black-headed Ibis Threskiornis melanocephalus. Downloaded from
https://datazone.birdlife.org/species/factsheet/black-headed-ibis-threskiornis-melanocephalus on 22/12/2024.
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 22/12/2024.