Lesser Adjutant Leptoptilos javanicus


Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - A2cd+3cd+4cd

Red List history
Year Category Criteria
2016 Vulnerable A2cd+3cd+4cd
2013 Vulnerable A2cd+3cd+4cd
2012 Vulnerable A2cd+3cd+4cd
2008 Vulnerable A2c,d; A3c,d; A4c,d
2006 Vulnerable
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened
Species attributes

Migratory status full migrant Forest dependency medium
Land mass type land-mass type - continent
land-mass type - shelf island
Average mass 4651 g

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 11,300,000 medium
Extent of Occurrence non-breeding (km2) 13,100,000 medium
Number of locations 11-100 -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 5500-10000 poor estimated 2013
Population trend decreasing poor suspected -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) 30-49 - - -
Decline (10 years/3 generation past and future) 30-49 - - -
Number of subpopulations 2-100 - - -
Percentage in largest subpopulation 1-89 - - -
Generation length (yrs) 16.1 - - -

Population justification: A total population of 5,000 individuals was previously estimated by Hancock (1993), Choudhury (2000) and BirdLife International (2001). However, more extensive survey effort in recent years has led to upward revisions of some national totals: in particular the Cambodian population is now thought to number perhaps 1,500-3,500 pairs or 3,000-7,000 mature individuals (Goes 2013, S. Mahood in litt. 2013). Taking this total and perhaps 1,200 mature individuals in India, c.300 in Malaysia, 200-700 in Nepal, 250-400 individuals in Myanmar (Zöckler et al 2014; in litt) plus an unknown number in Indonesia (previously estimated at 2,000 individuals in 1993 but may have severely declined since), and assuming only very small numbers elsewhere, the global population probably numbers 5,500-10,000 mature individuals (roughly equating to 8,000-15,000 individuals).

Trend justification: This species's population is suspected to be declining rapidly, in line with increasing levels of felling of colony nest trees, drainage and conversion of wetland feeding areas, agricultural intensification, pesticide use, disturbance and large-scale development in coastal areas, but, most seriously, the persistent and unregulated harvesting of eggs and chicks from colonies.
Successes in parts of Cambodia are likely to be isolated and may be short-term (C. Robson in litt. 2013), and declines are predicted to be ongoing elsewhere in the country . In Indonesia, estimates in South Sumatra and Jambi provinces in 1984-1986 were 514 birds (388-620) and 272 (152-475) birds respectively, while surveys in these provinces in 2001-2004 estimated only 124 birds (30-318) and 7 birds (2-17) respectively (M. Iqbal in litt. 2013), suggesting that very rapid declines may have occurred on Sumatra.

Country/territory distribution
Country/Territory Presence Origin Resident Breeding Non-breeding Passage
Bangladesh extant native yes
Bhutan extant vagrant
Brunei extant native yes
Cambodia extant native yes
China (mainland) possibly extinct native yes
India extant native yes
Indonesia extant native yes
Laos extant native yes
Malaysia extant native yes
Myanmar extant native yes
Nepal extant native yes
Singapore extinct native yes
Sri Lanka extant native yes
Thailand extant native yes
Vietnam extant native yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Bangladesh Hakaluki Haor
Bangladesh Sunderbans (East, South, West Wildlife Sanctuaries)
Bangladesh Teknaf Game Reserve
Brunei Brunei Bay
Brunei Seria Coast
Brunei Ulu Temburong
Brunei Wasan
Cambodia Ang Tropeang Thmor
Cambodia Boeung Chhmar / Moat Khla
Cambodia Chhep
Cambodia Chhnuk Tru
Cambodia Dei Roneat
Cambodia Lomphat
Cambodia Lower Stung Sen
Cambodia Mondulkiri - Kratie Lowlands
Cambodia Northern Santuk
Cambodia Prek Taek Sap
Cambodia Prek Toal
Cambodia Sesan River
Cambodia Snoul / Keo Sema / O Reang
Cambodia Sre Ambel
Cambodia Stung / Chi Kreng / Kampong Svay
Cambodia Stung / Prasat Balang
Cambodia Stung Kampong Smach
Cambodia Stung Sen / Santuk / Baray
Cambodia Upper Srepok Catchment
Cambodia Upper Stung Sen Catchment
Cambodia Veal Srongae
Cambodia Western Siem Pang
India Achanakmar Wildlife Sanctuary and Maniyari Reservoir
India Amangarh Reserve Forest
India Amarambalam Reserved Forest - Nilambur
India Amchang Hills
India Bandhavgarh National Park
India Bandipur National Park
India Barail Wildlife Sanctuary
India Bauwwa Beel
India Behali Reserve Forest
India Bhadra Wildlife Sanctuary
India Bhagwan Mahavir Wildlife Sanctuary (including Molem)
India Bherjan-Borajan-Podumoni Wildlife Sanctuary
India Bhindawas Wildlife Sanctuary
India Bhitarkanika Wildlife Sanctuary and National Park
India Bordoibam-Bilmukh Bird Sanctuary
India Bordoloni - Sampora
India Buxa Tiger Reserve (National Park)
India Carambolim Wetlands
India Chakrashila Complex
India Chandubi Lake and adjoining areas
India Chirang Reserve Forest
India Corbett Tiger Reserve
India D'Ering Memorial Wildlife Sanctuary
India Dadara-Pasariya-Singimari
India Dandeli Wildlife Sanctuary
India Deepor Beel Bird Sanctuary
India Deobali Jalah
India Dhansiri Reserve Forest
India Dibang Reserve Forest and adjacent areas
India Dibru - Saikhowa Complex
India Dihaila Jheel and other wetlands
India Dudhwa National Park
India Dum Duma, Dangori and Kumsong Reserve Forests
India East and North Karbi Anglong Wildlife Sanctuaries
India Farakka Barrage and adjoining area
India Garampani, Nambor and Doigrung
India Gibbon (Hollongapar) Sanctuary
India Gogabil Pakshi Vihar, Baghar Beel and Baldia Chaur
India Gorumara National Park
India Gumti Wildlife Sanctuary
India Harike Lake Bird Sanctuary
India Hazaribagh Wildlife Sanctuary
India Heerakund Reservoir and Debrigarh Wildlife Sanctuary
India Innerline (East) and Barak Reserve Forests
India Innerline (West) and Katakhal Reserve Forests
India Jaldapara Wildlife Sanctuary
India Jamjing and Sengajan
India Jengdia Beel and Satgaon
India Jhanjimukh - Kokilamukh
India Jhilmil Jheel Conservation Reserve
India Kachhudah Lake and Mahananda River Course
India Kajra Dhar and Raniganj Protected Forest
India Kanha National Park
India Katerniaghat Wildlife Sanctuary and Girijapur Barrage
India Kaziranga National Park
India Keibul Lamjao National Park
India Keoladeo National Park and Ajan Bande
India Kishanpur Wildlife Sanctuary
India Kuarbari Dalani
India Kukkarahalli Tank
India Kulik (Raiganj) Bird Sanctuary
India Kusheshwarsthan
India Laokhowa and Burhachapori Sanctuaries
India Loktak Lake
India Lumding Reserve Forest
India Madhav National Park
India Maguri and Motapung Beels
India Mahananda Wildlife Sanctuary
India Majuli
India Manas National Park
India Manas Reserve Forest
India Manjira Wildlife Sanctuary
India Marat Longri Wildlife Sanctuary
India Mokama Taal (Barah) Wetlands
India Mudumalai National Park
India Nagarhole National Park
India Nagzira Wildlife Sanctuary
India Nalabana Bird Sanctuary (Chilika Lake)
India Nameri National Park
India Navegaon National Park
India Naya Bandh Wetland Complex
India Okhla Bird Sanctuary
India Orang National Park
India Pabho Reserve Forest
India Pabitora Wildlife Sanctuary
India Pani-Dihing Bird Sanctuary
India Panna National Park
India Pilibhit Tiger Reserve
India Ranthambore National Park and Tiger Reserve
India Ripu Reserve Forest
India Sanjay Gandhi National Park
India Sareswar Beel
India Sibsagar Tanks
India Someshwara Wildlife Sanctuary
India Son Beel
India Subansiri
India Sultanpur National Park
India Sundarbans Biosphere Reserve (National Park)
India Sur Sarovar Bird Sanctuary
India Tadoba National Park and Andhari Tiger Reserve
India Tamaranga - Dalani - Bhairab Complex
India The Chapories of Lohit Reserve
India Tirap - Burhidihing
India Udhuwa Lake Bird Sanctuary
India Upper Dihing (East) Complex
India Upper Dihing (West) Complex
India Urpod Beel
India Valmiki Tiger Reserve and Saraiyaman Lake
India Velavadar National Park
Indonesia Alas Purwo
Indonesia Bali Barat
Indonesia Baluran
Indonesia Berbak
Indonesia Bukit Barisan Selatan
Indonesia Bukit Tigapuluh
Indonesia Danau Sentarum
Indonesia Delta Mahakam
Indonesia Gunung Palung
Indonesia Gunung Tilu-Simpang
Indonesia Hutan Kahayan
Indonesia Hutan Rawa Gambut Barumun-Rokan
Indonesia Hutan Rawa Gambut Siak-Kampar
Indonesia Kerumutan
Indonesia Lahan Basah Mahakam Tengah
Indonesia Lembah Sungai Negara
Indonesia Muara Gembong - Tanjung Sedari
Indonesia Muara Kendawangan
Indonesia Pesisir Pantai Jambi
Indonesia Pesisir Riau Tenggara
Indonesia Pesisir Timur Pantai Sumatera Utara
Indonesia Pulau Moyo
Indonesia Rawa Danau
Indonesia Rawa Pesisir Pantai Barat Tapanuli Selatan (Angkola)
Indonesia Rawa Tapus
Indonesia Rawa Tulang Bawang
Indonesia Segara Anakan - Nusa Kambangan
Indonesia Sembilang
Indonesia Siak Kecil
Indonesia Solo Delta
Indonesia Tanjung Koyan
Indonesia Tanjung Puting
Indonesia Tanjung Selokan
Indonesia Trumon - Singkil
Indonesia Ujung Kulon
Indonesia Way Kambas
Laos Dong Kalo
Laos Dong Khanthung
Laos Xe Kong Plains
Malaysia Bako-Buntal Bay
Malaysia Brunei Bay (Malaysia)
Malaysia Endau-Rompin
Malaysia Kinabatangan floodplain
Malaysia Klias peninsula
Malaysia Kulamba Wildlife Reserve
Malaysia Loagan Bunut National Park
Malaysia Matang coast
Malaysia North-central Selangor coast
Malaysia Panti forest
Malaysia Pondok Tanjung Forest Reserve
Malaysia Pulau Bruit National Park
Malaysia Sadong-Saribas coast
Malaysia South-east Pahang peat swamp forest
Malaysia South-west Johor coast
Malaysia Teluk Air Tawar-Kuala Muda coast
Malaysia Tempasuk plains
Myanmar Ayeyarwady Delta (including Meinmahla Kyun)
Myanmar Ayeyarwady River: Bhamo Section
Myanmar Ayeyarwady River: Myitkyina to Sinbo Section
Myanmar Hukaung Valley
Myanmar Indawgyi Lake Wildlife Sanctuary and surroundings
Myanmar Karathuri
Myanmar Pachan
Myanmar Upper Mogaung Chaung basin
Nepal Barandabhar forests and wetlands
Nepal Bardia National Park
Nepal Chitwan National Park
Nepal Dang Deukhuri foothill forests and west Rapti wetlands
Nepal Dharan forests
Nepal Farmlands in Lumbini area
Nepal Ghodaghodi Lake
Nepal Jagdishpur Reservoir
Nepal Koshi Tappu Wildlife Reserve and Koshi Barrage
Nepal Mai Valley forests
Nepal Nawalparasi forests
Nepal Parsa Wildlife Reserve
Nepal Sukla Phanta Wildlife Reserve
Nepal Urlabari forest groves
Sri Lanka Ampara
Sri Lanka Anuradhapura
Sri Lanka Bundala complex
Sri Lanka Kantale Tank
Sri Lanka Madura Oya
Sri Lanka Minneriya / Girithale / Kaudulla
Sri Lanka Padaviya
Sri Lanka Polonnaruwa
Sri Lanka Rugam Tank
Sri Lanka Senanayake Samudraya / Nilgala
Sri Lanka Udawalawa
Sri Lanka Yala
Thailand Chaloem Pra Kiet (Pa Phru to Daeng)
Thailand Ko Phra Thong
Vietnam Binh Dai
Vietnam Chu M'lanh
Vietnam Chu Prong
Vietnam Nam Cat Tien
Vietnam Tram Chim
Vietnam U Minh Thuong
Vietnam Ya Lop
Vietnam Yok Don

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Aquatic & Marine Artificial/Aquatic - Water Storage Areas (over 8ha) suitable resident
Artificial/Terrestrial Arable Land suitable resident
Forest Subtropical/Tropical Dry suitable resident
Forest Subtropical/Tropical Moist Lowland major resident
Marine Coastal/Supratidal Coastal Brackish/Saline Lagoons/Marine Lakes major resident
Marine Intertidal Mangrove Submerged Roots major resident
Marine Intertidal Mud Flats and Salt Flats major resident
Marine Intertidal Salt Marshes (Emergent Grasses) major resident
Savanna Dry suitable resident
Wetlands (inland) Permanent Freshwater Lakes (over 8ha) major resident
Wetlands (inland) Permanent Freshwater Marshes/Pools (under 8ha) major resident
Wetlands (inland) Permanent Rivers/Streams/Creeks (includes waterfalls) major resident
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Agro-industry farming Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Marine & freshwater aquaculture - Scale Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation, Ecosystem conversion
Biological resource use Fishing & harvesting aquatic resources - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Reduced reproductive success, Species mortality
Biological resource use Logging & wood harvesting - Unintentional effects: (large scale) [harvest] Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Ecosystem degradation
Biological resource use Logging & wood harvesting - Unintentional effects: (subsistence/small scale) [harvest] Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation
Energy production & mining Mining & quarrying Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation, Ecosystem conversion
Human intrusions & disturbance Work & other activities Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Species disturbance
Pollution Agricultural & forestry effluents - Type Unknown/Unrecorded Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Ecosystem degradation

Purpose Primary form used Life stage used Source Scale Level Timing
Food - human - - non-trivial recent
Pets/display animals, horticulture - - international non-trivial recent

Recommended citation
BirdLife International (2023) Species factsheet: Leptoptilos javanicus. Downloaded from on 02/06/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from on 02/06/2023.