Endangered White-winged Wood Duck's Habitat Threatened by Climate Change

Alarm bells ring for the white-winged wood duck (WWWD). Declared the state bird of Assam in 2003, the on-ground conservation situation of the bird has not improved in recent years. On the contrary, the bird could well go extinct.

The white-winged wood duck (Asarcornis scutulata) has been classified as endangered by the International Union for the Conservation of Nature (IUCN), since 1994. Only 800 individuals of this species are estimated to be left in the wild, out of which 450 individuals are known to be present in India. The bird is called Deo Hanh (the spirit duck) in Assamese, owing to its ghostly call. In India, this species can only be found in the northeast states.

“We have been conducting intensive surveys of the areas dominated by the white-winged wood ducks in Assam and Arunachal Pradesh, since 2018,” Rathin Barman of Wildlife Trust of India (WTI) told Mongabay-India. “The situation is not as good as we thought. We could spot only a few birds in Nameri and the adjoining areas, Dehing Patkai and Namdapha. There have been no bird sightings in Dibru Saikhowa (a national park located in the Dibrugarh and Tinsukia districts, originally created with an objective of protecting the habitat of endangered species like the white-winged wood ducks), for more than 20 years. There are many areas in eastern Assam, where the birds were spotted in the first year of our survey in 2018 but have completely disappeared by 2020.”

The white-winged wood duck is an inhabitant of the tropical evergreen forest, mostly confined to dense forests and wetlands and requires an average annual precipitation of about 1,000-1,200 millimetres. “Since climate change has already impacted many tropical forest areas, the white-winged wood duck habitats are now threatened by changes in temperature and precipitation,” explained Syed Ainul Hussain, a Senior Professor at the Wildlife Institute of India.

‘The habitat of the white-winged wood duck is likely to shift’

A recent study conducted to assess the impacts of climate change and the potential distribution of the white-winged wood duck in the Indian Eastern Himalayan (IEH) region for the 2050s and 2070s revealed that 436.61 square kilometres of highly potential habitat of the species would be lost by 2070.

The study also predicts a decline in the potential habitat in Arunachal Pradesh, Assam, Nagaland, Meghalaya and Tripura, under future climate scenarios. The changes in precipitation patterns of the wettest months (June to September), coupled with the decrease in precipitation in the warmest quarter (October to December) would further lead to habitat loss, the researchers found. Additionally, the temperature rise would result in the loss of many potential habitats in Tripura and Nagaland by 2070.

The habitat of the bird is likely to shift towards the western part of northeast India and towards Bhutan – specifically on the Assam-Bhutan border with Nameri National Park – from its current habitat in the eastern most states of northeast India. The West Garo Hills, which are located in Meghalaya and share a northern border with Bangladesh, are also likely to become a more suitable area for white-winged wood duck by 2070, according to the study. Published in September 2022, the study has been conducted by researchers from Wildlife Institute of India, Assam University, NGO Aaranyak and A.V.C College.

The objective of this new study was to understand the potential distribution of the white-winged wood duck in future climate scenarios, in order to facilitate the creation of immediate conservation plans and the mitigation of subsequent threats.

The study models revealed that the overall potential habitat of the white-winged wood duck in the IEH region, might shrink due to climate acceleration. Out of the total area of 2,73,490.36 sq. km, in the IEH region, only 5,123.21 sq. km. is predicted to be ‘highly suitable’ for the bird.

Currently, Assam includes a large portion (5.86%) of the potential area, followed by Nagaland (1.08%), Meghalaya (0.56%) and Arunachal Pradesh (0.17%), according to the study.

“This study potentially directs us to the future when the species habitat is likely to alter significantly with the change in climate, leading to further decline in the population. Species Distribution Modelling (SDM) (that uses computer algorithms to predict the distribution of species) is getting significant importance to prioritise conservation actions across the globe and there is a massive possibility in reversing species extinction,” Jyoti Das, Project Manager at EDGE of Existence Programme, Zoological Society of London and a member of Aaranyak, told Mongabay-India.

The study is crucial to determine the existent potential habitat of the species in order to save it from extinction, according to Hussain, who is also a co-author of the study. Human-induced change in land use also needs to be limited in their habitat, he added.

Anwaruddin Choudhury, a naturalist and wildlife expert who has extensively studied northeast India, who is not associated with the study said that smaller wetland habitats within tropical forests would be severely affected by climate change. “Human intervention may be required for survival of such micro-habitats. Since this is a long-term prediction up to 2070, things may not go as predicted but is a call to be alert,” he continued.

The bird is mainly dependent on forested wetlands of undisturbed forest areas, according to Barman of WTI. These wetlands are very shallow and small and climate change will affect them first.

“Even a very small change of weather might threaten these wetlands. The protection of the bird from poachers would not be sufficient for the survival of the bird in the coming years. We need to act proactively now to conserve the WWWD and its habitat,” said Barman.

A decreasing population

Assam, which has been the stronghold for the white-winged wood duck in India, has a long history of conservation efforts by various individuals and organisations pursuing to protect this enigmatic species.

A report on Project Deo hanh, the white-winged wood duck recovery project initiated by Wildlife Trust of India in 2018, says that the duck was first granted protection from hunting in 1937, when the Assam Government (then under British rule) restricted hunting of the ducks during the breeding season (April to September) and outside stipulated reserve forest areas of the state. The duck was later placed under Special Protected List by the Indian Board of Wildlife in 1952.

A lack of corrective interventions, however, meant that illegal hunting, egg and duckling poaching and destruction of forest habitats continued throughout this period. Despite being declared as the State Bird of Assam in 2003, in an effort to encourage further conservation of the species, the WWWD population has drastically declined over the years, both in its numbers and the extent of occupancy, according to the report.

Severe threats to the species-ranging areas include various anthropogenic activities such as encroachment for settlements and agriculture, deforestation, hunting, chemical pollution and large infrastructure developments, the report states.

“To save the WWWD’s integrity as a state bird, more government attention is required, as was done for the tiger and rhino. Furthermore, high-potential areas need more protection to save the metapopulation,” Jyotish Ranjan Deka, a researcher with Wildlife Institute of India and the corresponding author of the study told Mongabay-India.

There needs to be a systematic survey to determine the current population of the species and awareness is essential to understand the importance of birds, opines Animesh Hazarika, a researcher with Assam University.

Rubul Tanti, a researcher and co-author of the study, said the bird might sit at the peak of extinction if proper conservation management is not implemented in due time. Wetlands, which are the only food beds for the species’ survival, have dried up during the last decades and need a restoration approach in the upcoming years.

“Long-term conservation action plans and research activities, as well as support from aspiring ecologists and nature lovers, have become critical for the survival of the existing population,” added Tanti.

Wildlife expert Bibhab Kumar Talukdar who has completed a Ph.D. on the white-winged wood duck told Mongabay-India that the species warrants a proper recovery plan as the population in Assam is likely to be less than 200.

“If the rhino population could be increased from a dozen in 1905, to more than 2,800, similar proactive efforts can also contribute towards recovery of our state bird of Assam. It’s a challenge for the Assam Forest Department, but also carries equal opportunities for Assam to be the leader in recovery of White Winged Wood Duck,” Talukdar commented.

The synergies needed for proactive conservation

Many wildlife experts say that for any conservation model to succeed, massive support is needed to develop local leadership around the study area. This includes developing the capacity of local youth around the bird’s habitat to ensure strict protection by regular monitoring of the bird and the habitat, according to Jyoti Das.

“There is a need for research on the species’ local migration. We must also identify the important sites. The government and NGOs should come forward, especially in eastern Assam to protect those important sites and conduct mass outreach programmes highlighting the importance of the bird in the ecosystem,” Jyoti Das said.

Conservation breeding programmes might be handy to sustain this species in the coming years, according to Barman, who added that the Wildlife Trust of India and the Assam Forest Department are jointly working on a strategy document for the conservation of the endangered bird.

This story was first published in Mongabay India