Justification of Red List Category
In common with most large wetland species in Asia, this species is thought to be undergoing a population reduction, which is suspected to be moderately rapid. It faces the full gambit of threats, from hunting and disturbance at breeding colonies to drainage and conversion of foraging habitats to agriculture. It consequently qualifies as Near Threatened. However in some areas the species is increasing and further information is required to ascertain whether the population as a whole is decreasing less rapidly than currently suspected. Evidence to demonstrate this could result in the species being downlisted to a lower threat category.
The population is estimated to number up to 10,000 individuals in south Asia, plus up to another 10,000 in south-east Asia and up to 100 in east Asia (Q. Wang in litt. 2002). This is likely to total fewer than 20,000 mature individuals, and so the population is placed in the band 10,000-19,999 mature individuals. This equates to 15,000-29,999 individuals in total, rounded here to 15,000-30,000 individuals.
The species is suspected to be in moderately rapid decline owing to hunting, egg collecting, disturbance at breeding colonies, drainage and agricultural conversion. The area of mangrove habitat in Myanmar has declined (C. Zöckler in litt. 2016). A population decline is precautionarily retained here however in some areas the species is increasing with the species increasingly using man-made wetlands (G. Sundar in litt. 2016). New information on the global population trend is required to confirm the trend direction.
This species occurs in Japan (scarce non-breeding visitor), mainland China (probably breeds in Heilongjiang, but this is not confirmed; non-breeding visitors are rare along the east and south coasts, occasionally inland to Sichuan and Yunnan), Hong Kong (China) (regular winter visitor in small numbers with occasional summer records), Pakistan (scarce resident, principally in the Indus delta region), Nepal (frequent resident and summer visitor to the south-east), India (widespread and locally common in the west, scarce in the east; possibly increasing locally due to the spread of man-made wetlands; with rapid increases in Kerala [Nameer et al. 2015]), Sri Lanka (common resident in the lowlands, particularly the dry zone), Bangladesh (local visitor to coastal regions and the north-east), Philippines (rare non-breeding visitor to the south), Myanmar (uncommon but widespread non-breeding visitor, mostly along coastal wetlands; 730 counted in 1991, 800 at coastal sites only in 2010-2012 [Zöckler et al. 2014]), Thailand (formerly common resident, now uncommon winter visitor), Laos (only one record, a single bird prior to 1950), Vietnam (previously an abundant breeder, now a few large colonies remaining and still locally common), Cambodia (a fairly common resident in early 1960s; now scarce and local with small numbers breeding around Tonle Sap), Peninsular Malaysia (formerly occurred and probably bred in the west, but few recent records), Indonesia (scarce non-breeding visitor to Sumatra and northern Borneo, possibly breeding in Sumatra with c.2,000 birds estimated; numerous breeding colonies were recorded in Java early in the 20th century, but now local and declining (Collar et al. 2000). The Sumatran population is thought to have undergone a very rapid decline in recent decades (Iqbal and Hasudungan in press). Numbers declined from 120 individuals in 2010 to 35 in 2013 and further to 8 in 2015 in the Eastern Ayeyarwaddy delta (Moses and Zöckler 2015). While the East Asian population is extremely small (Q. Wang in litt. 2002 to Wetlands International 2002), those in South-East Asia and South Asia probably number fewer than 10,000 individuals each (Byers et al. 1995).
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 and Kittur 2013, G. Sundar in litt. 2016). 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).
It is vulnerable to drainage, disturbance, pollution, agricultural conversion, destruction of roosting and nesting sites, hunting and collection of eggs and nestlings from colonies. A combination of these factors has probably caused the decline.
Conservation Actions Underway
Landscape-scale monitoring of breeding and foraging populations on agricultural areas in South Asia has been coordinated by the International Crane Foundation and the Nature Conservation Foundation since 2011 (G. Sundar in litt. 2016). Conservation actions to reduce chick and egg collection and other forms of disturbance to the breeding colony at Prek Toal (the only known breeding colony in South-east Asia) have been in place since the late 1990s, with permanent teams of protectors employed since 2001. Since 2001, c.95% of waterbird egg and chick collection has been prevented at Prek Toal. Hunting mitigation work has been introduced in Myanmar (C. Zöckler in litt. 2016).
Text account compilers
Benstead, P., Mahood, S., Pilgrim, J., Taylor, J., Allinson, T, Ashpole, J
Kumar Koli, V., Mahood, S., Wang, Q., Gopi Sundar, K., Zöckler, C.
BirdLife International (2019) Species factsheet: Threskiornis melanocephalus. Downloaded from http://www.birdlife.org on 24/03/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 24/03/2019.