May 5, 2025
THIMPHU – In a glimmer of hope for one of the most endangered bird species in the world, Bhutan has recorded a modest but meaningful rise in the population of the White-bellied Heron (WBH), according to the 2025 Annual Population Survey conducted by the Royal Society for Protection of Nature (RSPN).
This year’s census documented 29 individuals, including 24 in the wild and five under human care at the WBH Conservation Centre (WBHCC). With fewer than 60 of these birds known to exist worldwide, Bhutan is home to nearly half the global population.
The survey, conducted between March 3 and 7, covered 17 of the 18 designated WBH habitat zones across the country. Researchers used a combination of satellite imagery, drone surveillance, and mobile data collection tools such as Epicollect5 to map sightings and assess threats. The Kholongchhu basin, designated Zone XIV, was not surveyed due to a lack of historical data.
The highest concentration of herons was observed in Zone III, which includes the middle Punatsangchhu, Burichhu, Sunkosh-Dagachhu, and Wakletar areas, with nine individuals, up from three the previous year. Zone V (Phibsoo Wildlife Sanctuary) followed with four individuals, doubling its 2024 count, while Zone XV (Jigmechhu and Wangchhu) also recorded four individuals.
Other zones reporting herons included Zone IX (Chamkharchhu), Zone VII (Goling and Tsiadang), and Zone II (Adha, Nagzhina, and Taksha), each with two individuals. Zone IV (Lower Punatsangchhu, Lamozingkha, Rangae, and Gumti) reported just one individual.
In total, herons were sighted in seven zones this year, down from nine zones in 2024.
Although Zone V gained two individuals, and Zones IX and XV each gained one, Zones II, IV, and VII saw their counts drop by one bird each. No herons were observed in remaining Zones.
Despite the overall population rise, researchers noted worrying declines in historically important habitats. No herons were sighted this year in the upper Punatsangchhu and Mangdechhu basins, with all 2025 sightings were confined to downstream areas.
Four active nests were documented, three in the Punatsangchhu basin and one in Mangdechhu. Two nests, located in Kisonachhu and Dagachhu, appeared well-established, while a third in Relangthang was still under construction. The Mangdechhu nest, discovered post-survey near Tsaidang village, contained two chicks.
The RSPN’s ongoing initiatives, ranging from habitat restoration to community outreach and ex-situ conservation, are contributing to stabilising the WBH population.
The WBHCC currently houses five individuals, including two juveniles raised from wild-collected eggs and chicks in 2024.
While the population growth is encouraging, experts emphasise that the species remains critically endangered, with continued threats from habitat loss, riverine degradation, and human disturbances.