The White-bellied Heron (<em>Ardea insignis</em>), one of the world’s rarest birds, is critically endangered with fewer than 60 individuals globally. Bhutan harbors the largest known population, offering a vital opportunity for species conservation under future climate uncertainty. This study presents Bhutan’s first nationwide, climate-informed habitat suitability model for the White-bellied Heron. Using 361 verified occurrence records from 2001 to 2024 and 24 environmental predictors including topographic, bioclimatic, and anthropogenic variables, we applied a weighted ensemble modeling framework that combines generalized linear models, generalized additive models, and random forest algorithms. Model weights were calibrated to improve predictive accuracy and ecological relevance. The framework supports spatial projections of current and future habitat distributions under Shared Socioeconomic Pathway 3 climate scenarios for the periods 2041 to 2060 and 2061 to 2100. Under baseline conditions (1996 to 2014), 8219 km² of Bhutan is identified as suitable habitat, expanding to 13,784 km² by 2100. However, projections reveal fragmentation and shifting suitability zones, particularly in unprotected districts such as Monggar and Pemagatshel. Protected areas like Royal Manas National Park retain high suitability, while others including Bumdeling Wildlife Sanctuary and Jigme Khesar Strict Nature Reserve may become unsuitable. These results should be interpreted with caution due to limitations in modeling dynamic anthropogenic pressures such as hydropower development, road expansion, and land-use change. The absence of spatial data on infrastructure footprints and fine-scale ecological filters may lead to overestimation of habitat suitability in certain regions. This study identifies protection gaps, proposes Other Effective Area-Based Conservation Measures, and emphasizes the need for connectivity and adaptive strategies. Bhutan’s proactive conservation planning offers a valuable model for climate-resilient biodiversity management.

Namdapha Tiger Reserve in the north-east Indian state of Arunachal Pradesh is the only stronghold of the Critically Endangered white-bellied heron Ardea insignis, of which - individuals remain in India.The Reserve is the heron's only known breeding location in the country (Mondal & Maheswaran, , BirdingASIA, , -) and may be a place from where the birds disperse to nearby localities in

Knowledge, attitude, perceived threats and conservation challenges of the critically endangered White-bellied Heron, Ardea insignis, in Bhutan

The discovery of White-bellied Heron Ardea insignis nesting in India in 2014 was a significant record since it was the second nesting report in India after one reported in Bhutan ‘dooars (= Terai)’ below Darjeeling. White-bellied Herons are known to build their nests in the riverine forests between 300 m and 1,500 m. The majority of the nesting records are from Chir Pine Pinus roxburghii forests of Bhutan. This article highlights heron’s nest site selection and nesting activities in the broadleaved forests in Arunachal Pradesh, India. During the study period (2013–2017) in Namdapha Tiger Reserve, two active nests of this species were recorded one in 2014 and another in 2015. Though both the nests failed without producing any offspring, the findings, shed crucial information, especially on how the herons select their nesting sites and nest trees and the risks involved in the process. These findings will help implement conservation actions especially while safeguarding the known nesting sites in India.

Although conservation efforts worldwide have transitioned toward landscape and regional approaches, species such as the White-bellied Heron <em>Ardea insignis</em> still require targeted actions because of their extremely small and declining population size and restricted distribution. In situations where every individual bird is critical to the population, conservation actions must be precise and effective, leaving little margin for error. Despite commendable conservation measures for the White-bellied Heron, especially in Bhutan, where a major population is found, the declining population trend is alarming, necessitating both short-term and long-term conservation strategies. This study sought to propose a measure to conserve the species by analyzing two decades of population, breeding, and mortality data using a Bayesian population viability analysis and integrated population model. Our analysis revealed that the annual survival rates of juveniles are remarkably low, and without new conservation measures, the population is expected to continue declining with high certainty. Under the current scenario, our models predict extinction probabilities between 10.4 and 26.6%, whereas the probabilities of population increase are only 6.2 to 14.0% for the next 30 years. Our models suggest that increasing juvenile survival rates by 20% and supplementing the wild population by releasing at least five captive-bred birds annually would improve the probability of population growth by 99% over the next 30 years. The newly established, White-bellied Heron Conservation Center will play a critical role in conserving the species through the provision of captive bred birds via the collection of eggs and chicks and raising them in captivity. The captive breeding program would provide a healthy breeding stock and representative genetic diversity, while at the same time, more chicks could be saved by raising them for the first year and safely releasing them back the following winter when the river volumes are low, and feeding grounds are comparatively safe and abundant. This would also enable breeding pairs to re-clutch and produce a second brood the same year. However, identifying and addressing the major cause of juvenile mortality and threats hindering wild population growth is crucial for reestablishing a self-sustaining wild population. This study demonstrates how limited and fragmented information can still be effectively utilized to make informed decisions for conserving vulnerable species in countries facing challenges in comprehensive research and monitoring.

Abstract The Critically Endangered white-bellied heron Ardea insignis is a large-bodied, range-restricted, piscivorous bird of the Himalayan mountains. With fewer than 60 individuals remaining globally, regular monitoring is required for this rare species. We present the results of surveys during 2017 and 2023–2024 in Namdapha Tiger Reserve, Arunachal Pradesh, India. The encounter rate of white-bellied herons in 2017 was 0.55 individuals per km of river, but we did not detect the bird during intensive surveys in the same location during 2023–2024. The surveyed area within the Reserve was once a stronghold for the species, but its population appears to be declining. Monitoring the population has helped reveal this decline, but identifying and conserving stretches of river still utilized by the remaining individuals is now critical.

This study explores and identify possible solutions to reduce crop damages due to Human-Wildlife Conflict (HWC) in the study areas.The study also provides information on types, extent and periods of damages, as well as perceptions and potential solutions to lessen crop loss and combat HWC.The study is supported by information gathered through the distribution of a questionnaire to Gewog1 Officials, Extension Agents2 and communities.The study's conclusions indicate that increasing incidences of HWC is associated with fragmentated wildlife habitats caused by rapid urbanization and infrastructure development, expanding agricultural activities, and regeneration of forest in fallow farmlands.The impediments in combating HWC issues are due to lack of enduring and effective long-term intervention measures.The study recommends installation of electric/solar and chain-link fencing around agricultural fields, development of compensation plans for farmers affected by wildlife, promotion and diversification of crops, and fostering community-based conservation programs involving local communities will strengthen harmonious balance between human and wildlife.

Birds play very essential ecological functions such as pest control, pollination, seed dispersal as well as nutrient dynamics and they are very good indicators of the ecosystem health in a landscape. Biodiversity inventory and their conservation including ecosystem restoration at landscape level has recently emerged as a global priority for effective management planning to ensure ecosystem stability and ecological functionality. This study aims to create a baseline database of avifaunal assemblages from the recently recognized Raimona National Park in the state of Assam, India. This new protected area is located in the Bhabar belt covering 422 km2 area under the Kachugaon forest division of the state. The systematic grid-based line transect method was followed from November 2020 to April 2021 and confirmed the presence of total 227 avian species from the study area among which 7 species were globally threatened. The area also harbours the suitable habitat of critically endangered White-bellied heron (Ardea insignis Hume, 1878). Extensive research and long-term monitoring will be very crucial in the near future for the inventory of more avian fauna along with their conservation in the Raimona National Park.

Floristic compositions and vegetative structures are key determinants for selecting nests and roosting habitats of Critically Endangered White-bellied Heron. However, none of the Bhutanese researchers had ever studied to date. Gradient-directed transect methods were adopted using systematic sampling. Vegetation surveys were carried out inside 10 x 10 m (trees), 5 x 5 m (shrubs), and 2 x 2 m (herbs) in 48 plots across the Pochu landscape. The result shows that the Phochu landscape recorded 10 trees species belonging to six families. Pinus roxburghii is the most dominant species with relative density [RD] (86.77%), relative frequency [RF] (37.50%), relative dominance [RD] (79.93%), and IVI (204.20). While, L. ovalifolia and A. lebbeck were the lowest (RD (0.53%), RF (6.25%), RD (0.07%), (0.83%), IVI (6.85), and 7.61 respectively. While shrub constitutes 19 species and belongs to 14 families. Chromolaena odorata (32.15%, n = 933) and Cymbopogon sp. (21.26%, n = 617) were the most dominant herbs, while, Galium aparine (0.03%, n = 1) were lowest with 38 herbs species belongs to 20 families. For vegetative structures, maximum trees (38.62%, n = 73) DBH ranges from the 11-15 cm, which are found in day roosting site 1 (34.25%, n = 25). While, lowest ((0.53%, n = 1) was DBH ranges of 51-55 cm, 61-65 cm, 66-70 cm and 71-72 cm respectively. Therefore, similar vegetation composition and structure studies are suggested in other core habitats across Bhutan to deduce its habitat ecology for the long-term conservation of Critically Endangered WBH in Bhutan.

The study was conducted in 2018 along the Mangdechhu river basin and Bertichhu stream of Zhemgang district, which are the important habitats for White-bellied Heron (Ardea insignis) in Bhutan. We have documented the anthropogenic threats, directly affecting the survival of the species through focal sampling along established transects at the study area. The major anthropogenic threats leading to the habitat degradation encountered were overhead hydropower transmission lines installed across the river/stream, firewood collection from riverbank, sand/stone quarry, temporary cattle herding camp and grazing, camping/picnicking and fishing. This study found that the sites used for foraging and resting by the species should be strictly monitored and protected from the human disturbances.

The critically endangered White-bellied Heron (Ardea insignis) is a piscivorous visual forager that prefers to forage in fast-flowing freshwater rivers. This study highlights White-bellied Heron foraging behavior in the fast-flowing rivers of Namdapha Tiger Reserve during 2013–2017. The herons spent significantly more time and also made more foraging attempts while foraging in shallow water (foraging time: 61.45 ± 15.55%; strike rate: 1.70 strikes/hr). Herons were more successful in catching fishes when they foraged facing upstream (capture rate: 0.62 fishes caught/hr) with increased capture efficiency (44.62%). White-bellied Herons caught the majority (60.98%) of small sized fishes (≤ 9 cm) while facing upstream and the majority (60.92%) of large sized fishes (> 18 cm) while facing downstream. These findings shed light on the manner in which this rare and critically endangered bird is adapted to life on fast-flowing rivers and the importance of these unique places for its conservation.

Birds are ecological indicators of ecosystem health. Baseline information on bird diversity are, therefore, important for ecological monitoring. Such information is, however, sorely lacking for many areas outside the protected areas. Here, we explore the avian diversity and present a comprehensive checklist for the non-protected regions of Trashiyangtse District in northeastern Bhutan. We also categorise the bird species by their residency pattern, feeding guilds, abundance, and IUCN Red List status. We conducted an avifauna exploration for a period of four years from 2017 to 2020, mostly through opportunistic encounters coinciding with regular field visits. We recorded a total of 273 bird species belonging to 173 genera, 69 families and 19 orders. Passeriformes was the most dominant order with 41 families and 174 species and Muscicapidae was the most dominant family with 12 genera and 32 species. Most birds were altitudinal migrants (39%), insectivorous (45%), and occasional (44%) in terms of residency pattern, feeding guild, and abundance, respectively. Only one species (Ardea insignis) was listed as Critically Endangered and one (Haliaeetus leucoryphus) as Endangered. Our study identified the non-protected regions of Trashiyangtse District as an important bird diversity area in Bhutan.

White-bellied Heron Ardea insignis is a critically endangered species. The population is in decline and the range significnatly shrinking. Here we report some recent sightings/photo proof of the species form one of the last refuges of the species in the Hkakabo Razi Landscape since 2016.

White-bellied heron a species on the verge of extinction: Ensemble model reveals loss of habitats and resultant prolonged isolation driving the species to extinction

Aquatic avifauna are an important bio-indicator of an ecosystem changes. Mizoram, one of the north-eastern states of India, lies in one of the richest biodiversity hotspots of the world. Along its water bodies, it is home to several species of resident birds, and is also a temporary home for migrating birds in different seasons. These resident and migratory avifauna form an important component of most wetland ecosystems, as they are vital components of the food webs. While only the Tamdil and Palak Lake are recognized as wetlands, there are several rivers and smaller water bodies around which aquatic avifauna exist. However, official records comprise of about 14 species of waterbirds belonging to 6 orders and 8 families. Of these, Anatidae, Charadriidae, Scolopacidae, Anhingidae, and Podicipedidae are represented by one species each, while the Ardeidae are represented by four species. Among the 14 species reported so far, two species of the Order Pelicaniformes, namely Anhinga melanogaster (Family Anhingidae) and Ardea insignis (Family Ardeidae) are highly endangered. However, detailed studies are wanting and, while there are sporadic reports of sightings on social media, there is a need for a more comprehensive study of the diversity and seasonal variations of aquatic avifauna around the different water bodies of the state of Mizoram.

SummaryWhite-bellied Heron Ardea insignis (WBH) is critically endangered, but we lack data on many aspects of its basic ecology and threats to the species are not clearly understood. The goal of this study was to analyse WBH foraging microhabitat selection, foraging behaviour, and prey preferences in two river basins (Punatsangchhu and Mangdechhu) in Bhutan which are likely home to one of the largest remaining populations of WBH. We also explored the relationship between the relative abundance of the WBH and prey biomass catch per unit effort within four foraging river microhabitats (pool, pond, riffle and run). Prey species were sampled in 13 different 100-m thalweg lengths of the rivers using cast nets and electrofishing gear. Riffles and pools were the most commonly used microhabitats; relative abundance was the highest in riffles. The relative abundance of WBH and prey biomass catch per unit effort (CPUE) also showed a weak but significant positive correlation (rs = 0.22). The highest biomass CPUE was observed in riffles while the lowest was found in the ponds. From the 97 prey items caught by the WBH, 95% of the prey were fish. The WBH mainly exploited three genera of fish (Garra, Salmo, and Schizothorax) of which Schizothorax (64%) was the most frequently consumed. This study provides evidence in support of further protection of critical riverine habitat and fish resources for this heron. Regular monitoring of sand and gravel mining, curbing illegal fishing, habitat restoration/mitigation, and developing sustainable alternatives for local people should be urgently implemented by the government and other relevant agencies. Further study is also required for understanding the seasonal variation and abundance of its prey species in their prime habitats along the Punatsangchhu and Mangdechhu basins.

Foraging activity patterns of critically endangered white-bellied herons (Ardea insignis) in Punatsangchu and Mangdechu river basins of Bhutan ―Conservationists for White-bellied Herons―

ABSTRACT The White-bellied Heron (Ardea insignis) is listed as a critically endangered bird species by BirdLife International due to the rapid population decline. Before this study, nothing was known about the night roosting behaviour of this imperiled species. Here, we report on the night roosting behaviour of the White-bellied Herons in Punatsangchhu and Mangdechhu river basins of Bhutan. There was a significant difference in landing and takeoff flights between the short- and long-day periods (P <0.05). Overall, the night roosting behaviour was dominated by sleeping (65 ± 11 min). We also documented two prominent behaviours that were thermoregulatory in function. The White-bellied Herons roosts solitarily on the tree branches in the night and makes extensive use of the night roosting trees. Therefore, night roosting trees are essential for consideration while assessing the home range size of the White-bellied Herons for their better conservation and management.

SummaryThe White-bellied HeronArdea insignisis currently known to be restricted to Bhutan, Myanmar, and north-east India. This ‘Critically Endangered’ species is under threat from the ever-changing river systems, primarily due to anthropogenic pressures including the large number of proposed hydropower projects. We report results of the first systematic, large-scale river survey for this species in the states of Arunachal Pradesh and Assam in north-east India with the aim of establishing its evidence-based distribution and assessing the severity of threats on the river systems in the region. We conducted river surveys along all seven major river basins in Arunachal Pradesh (October 2017–March 2018) and one in Assam (January 2019) along with 200 key informant surveys from 23 localities across the region. We encountered the White-bellied Heron six times in only three of 81 sites surveyed. Three interviewees reported observing the herons in three new localities, but we did not have a direct observation of the birds in any new sites. From field observations during the river surveys as well as the interview results, we found that certain fishing methods, garbage, and sand/gravel mining could be potential reasons for restricted occurrence of the White-bellied Heron in the region. Hunting is also a threat that prevails across the region. Our study calls for governmental commitment for the protection of the species and its vulnerable ecosystem and focussed research on understanding the anthropogenic impacts on the heron.

SummaryThis research evaluated the nesting habitat, nest-site preferences, and nest architecture of the critically endangered White-bellied HeronArdea insignisin Bhutan. There are fewer than 60 wild birds left in the world, distributed in Bhutan, India, and Myanmar with fewer than five active breeding pairs in Bhutan. From 2003 to 2018, 20 successful and two unsuccessful nests were located from which at least 76 juveniles were expected to have fledged. The population in Bhutan has remained at 22–30 individuals for the last decade. Site-specific data were collected from 22 nests, and additional vegetation and environmental data were collected from 14 nests and random sites. We used 20-m diameter circular plots to evaluate the site preferences. Ground vegetation, litter and rock cover were evaluated using four 1-m2quadrats in both nest and random sites. Nesting habitat was analysed to compare characteristics of nesting sites to random sites. Our results suggest that the White-bellied Heron builds a simple platform nest within average distance of 74 m from water bodies on the tallest isolated trees at an average height of 18.3 m on an elevated site with a clear overview of surroundings and are sensitive to even slight disturbance. Our results also suggest that the bird has a preference for an east-facing aspect at an average slope of approximately 40° between the altitudes of 400–1,450 m. Our observations also suggest that the bird has abandoned all nesting sites used prior to 2015, and the frequency of nest re-use has decreased. Protecting each nest site from hazards, avoiding disturbance, maintaining safe feeding habitats and flight routes are essential to ensure continued breeding in current sites and survival of this population. Further research to better understand the habitat requirements for the White-bellied Heron is vital.