Global Population
Less than 60 individuals
White-bellied Heron
Scientific Name: Ardea insignis
Common Name: Pho Bap (Dzongkha)
Individuals sighted in Bhutan (2026)
31
Population trend
Stable / Increasing
CR
IUCN Red List category
Critically Endangered
White-bellied Heron overview
Diet
Fish, frogs, crustaceans and other aquatic prey
Habitat
Undisturbed riverine and wetland habitats in subtropical and temperate forests
Distribution range
Bhutan, northeast India, and possibly Myanmar
Extent of occurrence
339,000 km²
Migratory status
Resident / partially migratory
Breeding endemic
Yes (Bhutan)
IBAs/KBAs identified
4
The White-bellied Heron (Ardea insignis), also known as the Imperial Heron, is one of the rarest and most critically endangered herons in the world. With a global population estimated at fewer than 60 individuals, it stands on the brink of extinction. Bhutan harbours one of the last viable populations of this species, making the country's conservation efforts crucial for its survival.
Standing nearly a metre tall, the White-bellied Heron is a large, grey heron distinguished by its white underparts, streaked neck, and stately posture. It inhabits undisturbed, pristine river systems and wetland habitats in the subtropical and temperate forests of the eastern Himalayas.
RSPN has been monitoring and conserving the White-bellied Heron in Bhutan since 2009, conducting annual population surveys, habitat assessments, and community awareness programmes across known heron habitats in the country.
Did you know?
Bhutan is home to 45% of global WBH population.
There is less than five known actively breeding WBH pairs in the world.
WBH is found in Bhutan, India and Mynmar - endemic to Himalayan foothills.
First WBH nest in Bhutan was discovered in 2003 - it was also rediscovery for the world after more than seven decades of previous record.
Fewer than 60 WBH are left in the world.
WBH is World’s Rarest Heron - Guinness Book of World Records, 2013.
Species assessment
IUCN Red List assessment
CR
Critically Endangered
Physical Description
The White-bellied Heron (Ardea insignis Hume, 1878) belongs to the family Ardeidae, order Pelecaniformes, and is found in freshwater ecosystems of the Himalayas. The species had a rather chequered nomenclatural history, having been linked with the specific names fusca, insignis and nobilis (Blyth 1844, Gray 1844, Gray and Gray 1846, Stray Feathers 6 [1878]: 470–472) as well as imperialis. Although insignis gained general acceptance, E. C. S. Baker (Bull. Brit. Orn. Club 49 [1928]: 40) later argued that its use was invalid (a nomen nudum) and renamed the species Ardea imperialis. However, it was later described by A. O. Hume in 1878 (Stray Feathers 6:470) as Ardea insignis (Sibley & Monroe 1990) and the accepted name now is Ardea insignis, the White-bellied Heron.
The White-bellied Heron (WBH) is a large water bird with long neck and leg, found along the open banks of freshwater river systems in the inner Himalayas. Its body is dark greyish with contrasting white throat, belly and vent, and white-streaked scapulars, fore neck and upper breast. Both males and females have two lace-like white plumes on the nape. During breeding seasons, plumage turns light grey with a whitish neck and crest. Juveniles appear darker than adults with more streaked on the neck, browner-tinged vent and smaller plume. It has a long and sharply pointed black bill with a serrated inside. The chin and lower mandible are whitish undersides while the upper mandible is black.
Scientific classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Aves
- Order
- Pelecaniformes
- Family
- Ardeidae
- Genus
- Ardea
Common Name
| English | Dzongkha | Lhotshamkha | Khengkha | Tshangla | Kurtoep/Dzalakha |
|---|---|---|---|---|---|
| White-bellied Heron | Chubja Phowkarp/Bja Eako Raem | Saray Haas, Raja Haas | Woong Rila | Ngangkha | Ngäp Bja |
Distribution
Global Distribution
Historically, the bird occupied a large area of the Himalayan foothills, from the plains of Nepal, across northern India including Sikkim, Darjeeling, West Bengal, Assam, Arunachal, and Nagaland, and Bhutan to southern Myanmar bordering with Thailand. During the second and third quarters of the 20th century, the species was extirpated from most of its historical range, restricting itself to Bhutan, Assam, Arunachal Pradesh, and northern Myanmar. The bird has been declared extinct from Nepal, and there are no recent records from West Bengal, southern Myanmar, and Bangladesh, suggesting that the overall range has contracted substantially. There are few records of observation from southern China.
Distribution in Bhutan
In Bhutan, WBH is distributed in temperate and mixed-broadleaf forests of major river basins: Punatsangchhu, Mangdechhu, and Wangchhu basin, at an altitudinal range of 100–1800 m. An optimistic habitat suitability model (Fig.1.2) predicts that only 3891.06 km2(10.13 %) of total area in Bhutan is highly suitable for WBH, an additional 5747.97 km2 (14.97 %) is suitable, and 93.83 km2 (0.24 %) is least suitable. The remaining 74.65 % (28661.12 km2) is not suitable, which comprises areas that fall above an altitude of 2000 m, near the settlement, built-ups, agricultural land and rocky outcrops.
The total population in Bhutan is estimated to be between 14 to 30 individuals based on annual simultaneous surveys from 2003 to 2025. In 2025, the annual population count recorded 29 individuals of WBH in Bhutan. Annually, one to five active nests have been recorded from 2003 to 2025 in Bhutan.
Threats
The threats from anthropogenic factors include activities resulting from the following:
- Natural resource extraction
- Hydropower development
- Tourism/recreation and livelihood activities, and
- Pollution
1. Natural Resource Extraction
Harvesting of natural resources from the critical habitats, such as sand and stone extraction, collection of driftwoods and NWFPs, herding of cattle, fishing, and carrying out other anthropogenic activities pose serious threats to WBH. Since WBH mainly forages along the freshwater river system, the activities that happen along riverine ecosystems are very sensitive. The disturbance through these activities involves flushing away of WBH during their foraging and nesting period. Activities like stone quarry and sand extraction degrade the feeding sites that exacerbate pressures on the existence of the species.
2.Hydropower Development
The development of hydropower in large rivers modifies the prime habitat of WBH and poses threat due to dams, power lines and hydropower infrastructure. Dams permanently change riverine ecosystems that alter foraging ground and also restrict the movement of fish which is the main diet to WBH. Power lines and electricity pylons across rivers and along with the migratory route threaten the movement of WBH and often lead to collision and electrocution.
3.Tourism and Recreation Activities
Tourism and recreational activities include rafting, camping, picnicking, and trekking in the critical habitats that bring threats to WBH. Unregulated timing and conduct of these activities in WBH habitat disturb the bird usually during the feeding periods which are mostly morning and evening hours.
4.Pollution
The development of new infrastructure facilities along river basins modifies the landscape and increases the generation of different types of waste that pollute both land and water bodies. The discharge of these wastes especially into the water may cause serious aquatic ecological disturbances that will impact the foraging behaviour of WBH.
5.Other anthropogenic threats
Other anthropogenic factors that pose threats to WBH include deforestation and human-induced forest fire. Increased agricultural expansion and infrastructure development increase the rate of deforestation and forest degradation that deteriorate the habitat and cause disturbances to WBH. Since WBH nests on trees, the occurrence of forest fires has serious implications during the nesting season.
6.Natural Factors
The threats from natural factors are a natural phenomenon that occurs in an ecosystem. However, when these natural factors are enhanced by the intervention of anthropogenic activities, it threatens the survival of certain species. Some of the natural factors that are observable in the current environmental condition and foreseeable threats to WBH are listed below:
- Climate Change
- Competitor species and predation
7.Climate change
Climate change is considered as one of the major threats to freshwater biodiversity as rivers fed with glaciers are more sensitive to climate change. In Bhutan, most of the rivers are fed by glaciers and glacier lakes. With the increase in temperature, these glaciers are retreating at a faster rate causing the floods downstream that change river courses and fish diversity which is the prime habitat and main food source to WBH.
8.Competitor species and predation
The presence of other piscivorous species like Great cormorants, Otters and Grey heron that share the WBH habitats also have an impact on WBH. Great cormorants, Grey Heron and all Otters species found in Bhutan have a similar ecological niche as WBH. The competition for food resources can exacerbate the declining WBH population in its habitat range. Heron hatchlings are also susceptible to predation by various natural predators like Pallas’s fish Eagle (Haliaeetus leucoryphus), Serpent Eagle (Spilornis cheela), Osprey (Pandion haliaetus), Yellow-throated marten (Martes flavigula) and other small cats. The predation risk increases when the parent herons are away from the nest for a longer duration of foraging.
Conservation Initiatives
RSPN has led conservation efforts for the White-bellied Heron in Bhutan since 2009. The programme combines systematic monitoring, habitat protection, community engagement, and policy advocacy to safeguard the remaining population.
Population Monitoring
Annual systematic surveys are conducted across known and potential heron habitats throughout Bhutan. Survey data are used to track population trends, identify key breeding sites, and inform conservation planning. The most recent surveys recorded 31 individuals in Bhutan in 2026.
Nest Site Protection
Known nest sites are monitored closely during the breeding season (February–May). Buffer zones around active nests are established in coordination with local communities and relevant government agencies to minimise disturbance during critical periods.
Community Engagement
RSPN works closely with local communities residing near heron habitats to build conservation awareness and develop sustainable livelihood alternatives that reduce pressure on river systems. Local community members are trained as conservation volunteers and monitors.
Research and Documentation
Ongoing research on the species' ecology, breeding biology, habitat requirements, and threats informs evidence-based management. RSPN collaborates with international partners, including BirdLife International and the IUCN Heron Specialist Group, to contribute to global conservation knowledge.
