This wide-ranging and long-lived species has a very small population which is declining very rapidly. For these reasons it is classified as Endangered. Recent breeding failures in Assam (the species's stronghold) provide cause for concern and need to be closely monitored.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.
Distribution and populationLeptoptilos dubius
145-150 cm. Huge, dark stork with very thick bill and pendulous neck-pouch. Pinkish naked head, white neck-ruff. Pale grey greater coverts and tertials contrasting with otherwise dark upperwing. Underwing-coverts paler than flight feathers. Juvenile has narrower bill than adult, denser head and neck-down and, initially, all dark wings. Similar spp. Lesser Adjutant L. javanicus is smaller, lacks neck pouch, has black greater coverts and tertials.
was previously widespread and common across much of South and continental South-East Asia but declined dramatically during the first half of the 20th century (Birdlife International 2001). It is known to breed in Assam, India
(at least 650-800 birds, or more [Choudhury 2000]
), and at the Tonle Sap lake (c.75 pairs) and in Kulen Promtep Wildlife Sanctuary in the Northern Plains (c.15-20 pairs), Cambodia
(T. Clements in litt
. 2007). The species was reported to be breeding in Bihar, India, in 2004, and a small breeding population was discovered in the state on the Ganga and Kosi river floodplains in 2006 (Mishra and Mandal 2009). The population there appears to be increasing, with at least 156 estimated in 2008 and over 300 individuals in 2011, up from 78 in 2007 (Mishra and Mandal 2009, Kahn 2011). Recent records from Nepal
, and Thailand
are presumed to refer to wanderers from India and Cambodia. Huge numbers once bred in Myanmar
, but there have been just two recent reports from Meinmahla Kyun in 1998 and Kachin State in 2006
(G Chunkino in litt
. 2006). There are no confirmed records from Laos in recent years. Breeding success in recent seasons has been extremely poor in Assam: the number of nests in colonies is declining sharply, but for unknown reasons (Goswami and Patar 2006)
. Despite this, large flocks of a few hundred birds are still noted around the city of Guwahati, which may provide feeding areas for around half of the species's world population (Choudhury 2008). Available data suggest that Cambodian populations declined heavily in the decades up to and including the 1990s. By 2001, several breeding sites recorded in the 1990s had been abandoned. Since 2001, protection measures at two known breeding sites (Prek Toal on the Tonle Sap and Kulen Promtep in Preah Vihear) have led to a stabilisation of national population declines and possible minor recoveries (Clements et al
. 2007a, b). Population justification
The total population is estimated to number 800-1,200 mature individuals, roughly equivalent to 1,200-1,800 individuals in total. This is based on estimates of 650-800 birds in Assam, India, plus 150-200 birds in Cambodia, as well as at least 156 birds in Bihar state, India, which may have dispersed from the Assam population.Trend justification
This species's population is suspected to be decreasing very rapidly, in line with levels of direct exploitation and habitat destruction, particularly lowland deforestation and the felling of nest-trees, and drainage, conversion, pollution and over-exploitation of wetlands. Given the species's longevity, population trends are measured over a three-generation period of 45 years and hence the impacts have been severe.Ecology
While breeding in the dry season (October-May/June) it inhabits wetlands, nesting in tall trees, bamboo plantations and historically on cliffs. Breeding is thought to coincide with the dry season in order to take advantage of abundant prey as water levels recede (Singha et al
. In north-east India, it occurs close to urban areas, feeding around wetlands in the breeding season, and dispersing to scavenge at rubbish dumps, abattoirs and burial grounds at other times. In Cambodia, it breeds in freshwater flooded forest and areas of dry forest with ephemeral pools, otherwise dispersing to seasonally inundated forest, carcass dumps, tall wet grassland, mangroves and intertidal flats. Threats
The key threats are direct exploitation, particularly at nesting colonies, habitat destruction, including some felling of nest-trees, and drainage, conversion, pollution and over-exploitation of wetlands. Additionally, the Indian population is threatened by reduced use of open rubbish dumps for the disposal of carcasses and foodstuffs. It has been suggested that recent nesting failures in Assam may be due to disease (Goswami and Patar 2006)
, which may have a negative impact upon the species in the future. Young birds may also become entangled in fishing nets and the species may suffer from the disturbance of arboreal animals, competition for nesting habitat from the Lesser Adjutant L. javanicus
and the exacerbation of persecution levels owing to its pest status (Mishra and Mandal 2009). Poisoning of small wetlands to catch fish in the dry forests of northern and eastern Cambodia potentially poses a significant threat, and in Guwahati, India, pesticide use at open rubbish dumps where storks flocked to feed led to several mortalities in 2005. Conservation actions underway
In Assam, it occurs in Kaziranga, Manas and Dibru-Saikhowa National Parks. Since 1991, there have been conservation awareness programmes in Assam. In Nagaon district, Assam, Green Guards (a local NGO) had a project to protect nesting trees and rehabilitate chicks fallen from nests but this has now stopped (A. Choudhury in litt.
2012). In Cambodia, the breeding colony at Prek Toal is a core area of the Tonle Sap Biosphere Reserve. Greater Adjutants historically bred at other sites on the Tonle Sap, but these colonies were abandoned by 2001. Conservation actions to reduce chick and egg collection and other forms of disturbance to the breeding colony at Prek Toal have been in place since the late 1990s, with permanent teams of protectors employed since 2001. The small population in the Northern Plains is largely protected within Kulen Promtep Wildlife Sanctuary. Since 2001, c.95% of waterbird egg and chick collection has been prevented at Prek Toal. It is included in waterbird conservation awareness material in Laos and Cambodia. Conservation actions proposed
Conduct further surveys in Cambodia, Myanmar and Bangladesh. Investigate seasonal movements and threats. Protect nesting and feeding-sites outside protected areas, and plant trees in suitable areas; the nest payment system in Cambodia may be a suitable model. Rewarding the owners of nesting trees may be a means to encourage pride in the conservation of the species (A.R. Rahmani in litt.
2012). Promote strict control of pesticide use around feeding areas. Continue and strengthen on-going conservation actions at the Prek Toal colony, Tonle Sap lake. Establish a wildlife protection office at Tonle Sap lake. Draft and enforce waterbird conservation legislation at Tonle Sap lake. Expand conservation awareness programmes. Initiate a relief programme and promote alternative livelihoods to communities dependent on harvesting large waterbird colonies in Cambodia. Widely implement a policy of rescuing, rehabilitating and releasing chicks that fall from nests for natural reasons, such as during thunder storms (Singha and Rahmani 2006, Singha et al. 2006), and consider placing nets under nest-trees and conducting regular checks at colonies (Singha et al. 2006).
Choudhury, A. 2000. The birds of Assam. Gibbon Books and WWF-India, Guwahati, India.
BirdLife International. 2001. Threatened birds of Asia: the BirdLife International Red Data Book. BirdLife International, Cambridge, U.K.
Singha, H.; Rahmani, A. R.; Coulter, M. C.; Javed, S. 2003. Breeding behaviour of the Greater Adjutant-Stork Leptoptilos dubius in Assam, India. Journal of the Bombay Natural History Society 100(1): 9-26.
Goswami, S. K.; Patar, P. J. 2007. Fall in the number of Greater Adjutant nests in Nagaon, Assam, India.
Clements, T. J.; O’Kelly, H.; Sun, V. 2007. Monitoring of Large Waterbirds at Prek Toal, Tonle Sap Great Lake, 2001-2007.
Clements, T.J., Garrett, L., Tan, S., Kong, K.S., Pech, B., Thong, S.; Rours, V. 2007. Bird nest protection programme in the Northern Plains 2003-2007.
Choudhury, A. 2008. Counting large gatherings of globally threatened Greater Adjutant Leptoptilos dubius. Indian Birds 4(4): 133-135.
Mishra, A.; Mandal, J. N. 2009. Discovery of a breeding ground of the Greater Adjutant Leptoptilos dubius and their conservation in the floodlands of Bihar, India. Journal of the Bombay Natural History Society 106(2): 190-197.
Singha, H.; Rahmani, A. R. 2006. Ecology, population and conservation of Greater Adjutant Leptoptilos dubius in Assam, India. Journal of the Bombay Natural History Society 103(2-3): 264-269.
Singha, H.; Goswami, S. K.; Phukan, R.; Talukdar, B. K. 2006. Rehabilitation of captive-reared Greater Adjutants Leptoptilos dubius in Assam. Journal of the Bombay Natural History Society 103(2-3): 315-320.
Kahn, I. 2011. Endangered Garuda takes wing in Bihar. News One.
Further web sources of information
Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).
View photos and videos, and hear sounds of this species from the Internet Bird Collection
Text account compilers
Benstead, P., Bird, J., Butchart, S., Davidson, P., Peet, N., Pilgrim, J., Taylor, J., Tobias, J.
Choudhury, A., Chunkino, G., Clements, T., Htin Hla, T., Li, Z., Rahmani, A.
IUCN Red List evaluators
Butchart, S., Symes, A.
BirdLife International (2013) Species factsheet: Leptoptilos dubius. Downloaded from
http://www.birdlife.org on 22/05/2013.
Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from
http://www.birdlife.org on 22/05/2013.
This information is based upon, and updates, the information published in BirdLife International (2000)
Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004)
Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.
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Additional resources for this species