Milky Stork Mycteria cinerea


Justification of Red List Category
This stork has been uplisted to Endangered because recent population estimates from its stronghold in Sumatra suggest that it is undergoing a very rapid ongoing population decline owing to intense hunting pressure at nesting colonies, human disturbance and the rapid loss and conversion of coastal habitat.

Population justification
The global population was previously thought likely to total fewer than 5,000 individuals, roughly equating to 3,300 mature individuals, based on estimates of c.5,000 individuals in Sumatra in the late 1980s (Silvius and Verheugt 1989), 100-150 individuals in Java (M. Silvius in litt. 2002), 10 birds in Malaysia and 20-40 in Cambodia. Recent estimates put the global population far lower, at around 2,200 birds, based on totals of c.1,600 in Sumatra (c.75 individuals in Aceh province, c.500 North Sumatra province, c.350 Riau province, c.100 Jambi province, c.500 South Sumatra province and c.75 Lampung province), c.500 individuals, but possibly fewer, on Java, and <100 birds on the mainland of South-East Asia (Iqbal et al. in prep). Large declines are being seen in South Sumatra with declines of 70% over 22 years from 1986 to 2008 (Iqbal et al. 2012). At least 100 birds were observed in recent survey on 2014 in Rawa Aopa Watumohai National Park, Southeast Sulawesi (Iqbal pers.obs). This roughly equates to 1,500 mature individuals.

Trend justification
This species's population is suspected to be declining very rapidly in line with intense hunting pressure at nesting colonies and the rapid loss and conversion of coastal habitat. Estimates for Sumatra, which holds the bulk of the global population, fell from 5,000 birds in 1986 (Silvius 1988, Silvius & Verheugt 1989), to 1,600 in 2009 (Iqbal et al. in prep). In Java, a wintering flock in east Madura of 170+ birds observed in 1996 had diminished to c.70 birds in 2006, which may be representative of an island-wide decline (B. van Balen in litt. 2013). Numbers in Malaysia fell from counts of over 100 individuals in 1984, to fewer than 10 birds in 2005, and only a single wild bird in 2010 (Malaysian Nature Society 2005, Li et al. 2006, DWNP 2010). The tiny Cambodian population may be relatively stable, but at the global scale very rapid ongoing declines of 50-79% in three generations (25 years) are estimated.

Distribution and population

Mycteria cinerea occurs in Cambodia, Peninsular Malaysia and the islands of Sumatra, Java, Bali, Sumbawa, Sulawesi and Buton, Indonesia (BirdLife International 2001). The vast majority are in Indonesia, with perhaps 1,600 birds on Sumatra in 2008-2009 (down from estimates of c.5,000 in the late 1980s) and <500 in west Java (Iqbal et al. in prep.) There are records from elsewhere in Indonesia, including Sulawesi, Bali, Lombok and Sumbawa (Birdlife International 2001), but little recent information and no known breeding colonies. There are estimated to be c.10-20 pairs at Tonle Sap lake, Cambodia (J. Eames in litt. 2006), with 17 pairs in 2010 (van Zalinge et al. 2011). It is a vagrant to Thailand and Vietnam. Numbers have apparently declined in most parts of its range, with counts from Malaysia falling consistently from over 100 individuals in 1984, to fewer than 10 birds in 2005 (Malaysian Nature Society 2005, Li et al. 2006), and only a single wild bird was recorded in the Matang Mangrove Forest in 2010 (DWNP 2010). On Sumatra, although good numbers can still be found at some sites in South Sumatra province it has apparently declined considerably (Li et al. 2006, M. Iqbal in litt. 2006, Iqbal and Hasudungan 2008, Iqbal et al. in prep.). The largest counts in recent years have included 500 birds in 2005 in Muara Padang subdistrict, South Sumatra (Iqbal & Hasudungan 2008), up to 300 individuals estimated at Kumpai lake (South Sumatra) in 2008 (Iqbal et al. 2012), and a maximum count of 278 birds at Bagan Percut (North Sumatra province) in 2005 (Shepherd & Giyanto 2009). Also some important non-breeding areas along north coast of Java, south coast of central Java (Segara Anakan) and eastern part of Madura Island (B. Balen in litt. 2016).  A few pairs were still breeding on Pulau Rambut, Jakarta Bay in 2014 (C. Robson in litt. 2016).


It is a predominantly coastal resident in Indonesia and Malaysia, inhabiting mangroves and adjacent, less saline, swamps. It forages on tidal mudflats, in saline pools, freshwater marshes, fishponds and rice-fields. The species has been documented as eating fishes, prawns and crabs (Iqbal et al. 2008, 2009). Birds only occur inland in flooded forest around Tonle Sap lake in Cambodia, from where they disperse in the wet season, possibly to the coast (van Zalinge et al. 2011). Tall, mature trees are important for nesting (Ismail and Rahman 2016). In Prek toal Ramsar site, peak nesting occurs between February and April (Visal and Mahood 2015).


In Indonesia, tidal forests including mangroves are threatened by agricultural conversion and development schemes, particularly large-scale fish farms and tidal rice cultivation, logging and related disturbance; as a result, mangrove clearance has been rapid. Hunting for food and trade also exerts a significant pressure throughout its range. In 1989, 40-50 birds were shipped to zoos across South-East Asia. Persecution and disturbance at nesting colonies are thought to be the main threat in Malaysia. The same is said to be the case in South Sumatra, where local people hunt the species and take chicks and eggs for food and domestication (Iqbal et al. 2008). Hunting of chicks is thought to have largely impacted subpopulations at Kumpai lake and Kuala Puntian with respective declines of 80% and 73% between 2005 and 2008 (Iqbal et al. 2012). In Cambodia, exploitation of waterbird eggs and chicks and snaring of adults, for food and trade, coupled with the increasing likelihood of conversion of flooded forest for agriculture, threaten the Tonle Sap lake breeding colony, although the small population here is currently well-protected. Poisoning may be another significant, as yet unquantified, threat. Hybridisation with with Painted Stork M. leucocephala has occurred at Ang Trapeang Thmor Sarus Crane Reserve, Cambodia in 2007 and 2008, as well as in captive populations, including free-flying birds (Eames 2007, Yong D. L. in litt. 2011, J. C. Eames in litt. 2011). The potential spread of Milky and Painted Storks from an unringed and full-winged colony at the National Zoo in Kuala Lumpur is a potential threat to pure wild stock (D. Bakewell in litt. 2013). These Painted Storks have now reached the Selangor coast, and if they move northwards cross-breeding with the Milky Storks in Matang could be a possibility - hybrids have already been reported in the greater Klang Valley (Y. C. Aik in litt. 2012). Free-flying Painted and Milky Storks also occur at Singapore Zoo, and hybridisation has apparently produced reproductively viable offspring (Yong D. L. in litt. 2011), raising the possibility that these birds could cross to Sumatra and mix with key Milky Stork populations. Conversion of mangrove forest to fish-ponds is likely affecting the remaining population in Sulawesi (M. Iqbal in litt. 2016). 

Conservation actions

Conservation Actions Underway
CITES Appendix I. Colonies are located in at least five protected areas in Sumatra and one each in Java, Sulawesi and Peninsular Malaysia. At Tonle Sap lake, Cambodia, large waterbird breeding colonies are designated core areas of the Biosphere Reserve, are proposed as Ramsar Sites, and have received active monitoring and improved enforcement of regulations since 1997. In Cambodia, posters depicting the species are used in promoting public environmental awareness. The Milky Stork Breeding and Re-introduction Programme, run by a number of stakeholders, coordinates the captive breeding and release of individuals into the Kuala Selangor Nature Park, Malaysia (Malaysian Nature Society 2005). Between 2007 and 2014, 50 Milky Storks were released in Kuala Gula (Ismail and Rahman 2016). Efforts are underway to effect legislative protection of the Matang Mangrove Forest Reserves in Perak, Malaysia, and advocacy is being used as an additional tool in the species's conservation (Malaysian Nature Society 2005). Successful breeding in captivity, survival of free-flying released birds, and attempted nesting in the wild by captive-bred individuals has been achieved in Malaysia (Malaysian Nature Society 2005). Successful hatching of two chicks occurred in 2010 (DWNP 2010) and 2013, but not in 2014 due to indirect human disturbance (Ismail and Rahman 2016). Surveys of the population in Sumatra took place in 2008-2009 (Iqbal et al. in prep).

Conservation Actions Proposed
Conduct surveys and research to locate additional colonies, monitor seasonal movements and clarify its ecological requirements. Monitor numbers and breeding success at all known important nesting colonies. Establish additional protected areas encompassing important nesting colonies and feeding areas, particularly in the Riau, Jambi and Sumatra Selatan provinces of Sumatra and Matang Mangrove Forest in Malaysia. Promote public-awareness initiatives highlighting its conservation importance. Improve captive pre-release training techniques. Maintain and increase public awareness to ensure long term viability of the reintroduction program.


92-97 cm. White stork with thick, yellowish bill and blackish flight feathers. Juvenile has paler brown, more streaked head and neck, and darker wing-coverts contrasting sharply with upperparts. Similar spp. Painted Stork M. leucocephalus has black markings on wing-coverts and breast, pink on inner wing-coverts and tertials and more restricted naked head skin.


Text account compilers
Benstead, P., Bird, J., Davidson, P., Mahood, S., Peet, N., Pilgrim, J., Taylor, J., Tobias, J., Martin, R, Symes, A., North, A.

Li, Z., Goes, F., Mahood, S., Eames, J.C., Iqbal, M., Yeap, C., Robson, C., Yong, D., Chamnan, H., Brickle, N., Evans, T., Bakewell, D., van Balen, B.

Recommended citation
BirdLife International (2022) Species factsheet: Mycteria cinerea. Downloaded from http://www.birdlife.org on 01/07/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 01/07/2022.