World’s rarest heron on the brink of extinction in Bhutan
The white-bellied heron, found in the freshwater ecosystems of the Himalayas, is the most endangered species of heron in the world. Classified as Critically Endangered on the Red List of the International Union for the Conservation of Nature since 2007, its total world population is estimated at only 50 adult birds – 249 adult birds, and numbers are declining even more.
According to the conservation NGO Birdlife International, the species is already extinct in Nepal and possibly also in Bangladesh, with the entire world population now limited to northern Myanmar, northeast India and Bhutan.
Known locally as Chubja, Bhutan is home to about 45-50% of the world’s total population of white-bellied herons, and the highest known number of breeding pairs.
But a recent study is also of concern for the species in Bhutan. In March, the annual survey of the white-bellied heron population by the Royal Society for the Protection of Nature of Bhutan, a civil society organization, has identified 22 herons: 19 adults and three subadults. This is a decrease of five from the 27 birds in 2020.
White-bellied herons were seen in 10 locations during the 2021 survey: six of them were in the Punatsangchhu River basin in the western district of Wangduephodrang, where a total of 14 individuals were recorded. The other four sites were in the Mangdechhu River basin in the central Trongsa district, where eight herons were sighted.
Worryingly, for the first time in 19 years, in 2021, no white-bellied herons were seen in the Pochhu and Mochhu river basins in the central Punakha district, which was once home to the largest and oldest population. known from Bhutan. In addition, none have been recorded in the Kurigongri Basin and the Lower Mangdechhu Basin in Mongar District in eastern Bhutan this year.
The 2021 survey report also revealed population declines in places like Adha and Nangzhina in the Lower Punatsangchu Basin and nearby areas of Wangduephodrang District, which were prime feeding and nesting habitats for the species before 2010.
In 2020, a white-bellied heron was first spotted at a new location in the Chamkharchhu Basin in the central Zhemgang district. Chamkharchhu is currently one of the few rivers in Bhutan without ongoing development activities, such as sand and stone mining or the construction of hydroelectric dams.
In 2020, a bird was also recorded spending around two weeks for the first time at Bumdeling Wildlife Sanctuary in the high altitude district of Trashi Yangtse. No white-bellied herons were spotted in these new locations in 2021.
Threats to the heron
Indra Prasad Acharja, head of the species and habitat conservation division at the Royal Society for the Protection of Nature, said The third pole that the conversion of major rivers for hydroelectric development, expansion of agriculture and development for tourism are major threats to herons in Bhutan. The Royal Society for the Protection of Nature Strategic Plan for the White-bellied Heron 2019-2039 highlighted the threat that hydropower projects pose to the heron and its habitat, noting that related developments like grid electrification are also causing major disruption.
Additionally, where natural riparian ecosystems persist, the habitat of the White-bellied Heron is under pressure due to the extraction of resources such as timber, sand and stones, and loss of prey due to overfishing. . Herons are also threatened by hunting and noise pollution caused by the development of roads, said Indra Acharja.
Young herons often strike objects such as power lines when leaving the nest 70 to 75 days after hatching, sometimes dying from injuries. This is in addition to the predation, nesting failures and disturbances that herons would naturally face.
According to the Royal Society for the Protection of Nature, the fact that the total number of recorded white-bellied herons has not increased from previous years, despite at least six juveniles and three active breeding pairs recorded each year, is likely due to the presence of juvenile mortality. “The small genetic pool of the bird, [with] less than five breeding pairs, is one of the biggest threats to its existence, ”Acharja added.
Save the white-bellied heron
On June 10, two young white-bellied herons managed to leave their nest in Tsaidang, near Mangdechhu and Tingtibi, said Damber Bdr Chhetri, 36, a ranger at Royal Manas National Park and a belly heron conservation volunteer. white with the Royal Society for the Protection of Nature.
Damber said The third pole that he started volunteering after spotting three herons in Tsaidang in 2018. “I was with RSPN [Royal Society for the Protection of Nature] researchers back then when I was able to watch the birds for about a month, ”Damber said. “It was heartwarming to see how much the herons care about each other.”
Damber is one of the many foresters and residents of Bhutan who volunteer for the White-bellied Heron Local Conservation Support Group established by the Royal Society for the Protection of Nature.
The year 2003 marked the launch of the Royal Society for the Protection of Nature’s annual survey of the white-bellied heron population. In the same year, the Royal Society for the Protection of Nature discovered its first white-bellied heron nest in Zawa near Harachhu in the lower Punatsangchu basin. This prompted them to launch a full-fledged conservation program.
Over the past 16 years, researchers from the Royal Society for the Protection of Nature have identified 22 nests, up to five active breeding pairs per year and 14 active feeding localities, said Indra Acharja.
The white-bellied heron was first photographed in Bhutan in 1976 by the then fourth king, Jigme Singye Wangchuck, at Phochhu in the Punakha district. In Bhutan, the white-bellied heron is listed in Annex I of the Forests and Nature Conservation Act 1995, which means that the species is totally protected and cannot be killed, injured, captured or captured.
In 2011, the Royal Society for Protection of Nature, in collaboration with the Department of Livestock and the Department of Forests and Park Services, launched a program pilot program to breed captive white-bellied herons in Pochu in the central Punakha district of Bhutan. That year, the program successfully hatched a chick, which Survived and was subsequently released into the wild.
It was followed, in 2015, by a international meeting entitled “fostering international cooperation for the conservation of the critically endangered white-bellied heron”. The meeting endorsed the need to build a captive breeding center in Bhutan.
Indra Prasad Acharja said The third pole that the Punatsangchu hydroelectric project funded the construction of the new center at Changchey in Tsirang district, southwestern Bhutan, which is now completed.
Acharja explained that after a series of consultations between the Royal Society for the Protection of Nature and the authorities of the hydroelectric project, the management of the hydroelectric project agreed to fund mitigation programs for endangered species such as the heron in white belly. This led the project authorities to grant 50 million Bhutanese ngultrum for the construction of the captive breeding center.
At the captive breeding center, the Royal Society for the Protection of Nature plans to have a founding population of wild-caught birds which they hope will breed and produce chicks that can be released into the wild. nature in order to revive the population.
“Captive breeding aims to help tackle the high juvenile mortality rates due to predation and other calamities,” Acharja said, adding that the center would also serve to maintain a gene pool for the species. .
Taking some of the last remaining individuals of a critically endangered species captive has proven to be an effective strategy for several other species, including the California condor. The last 27 wild individuals of this rare species of American vulture were captured in 1987, and after captive breeding and release, the number in the wild has now reached more than 300.
But with numbers so low, any incident during capture or captivity could be catastrophic, as happened when one of the world’s last vaquita – a porpoise endemic to Mexico – deceased after being captured for an aborted conservation breeding attempt in 2017.
Other conservation efforts are underway to protect the world’s last white-bellied herons. In Royal Manas National Park, where forester Damber Bdr is currently based, fishing is controlled by the Forestry Department and Park Services to preserve heron prey. Bhutan’s Ministry of Forests and Agriculture also controls fishing in the Pochu and Mochu basins, as well as along the Punatsangchu River.
The Royal Society for the Protection of Nature has also worked to provide local people living in areas where the species is frequently observed with alternative sources of income such as fishing ponds and organic market gardening, in order to reduce dependence on neighboring rivers for fishing. They also organize awareness and education programs on the conservation of the white-bellied heron.
“As we try to ensure that the habitats of the white-bellied herons are protected and free from human disturbance, the organization also faces financial challenges,” said Indra Prasad Acharja.
Conserving herons is expensive, Acharja explained, involving conducting annual surveys, protecting places where birds are frequently seen, and funding local livelihood projects to reduce reliance on rivers for fishing. .
To study the movements of the herons, the organization used small GPS units attached to the birds, each costing around $ 4,000, and in the case of the white-bellied herons, they typically only last about three months. “Although we receive financial support from international and local supporters, we still face financial challenges to cover all conservation expenses and also need financial support to conduct more studies,” he said. declared Acharja.
Additional reporting by Aron White.
This article first appeared on The third pole.