WII Digital Repository
Established in 1982, Wildlife Institute of India (WII) is an internationally acclaimed Institution, which offers training program, academic courses and advisory in wildlife research and management. The Institute is actively engaged in research across the breadth of the country on biodiversity related issues.
The Institute's idyllic campus that has been carefully developed to create state of the art infrastructure encourages scholarly work.
This Repository is the digital asset management system which integrates the intellectual output in the form of research articles, Theses and other scanned documents. This Repository facilitates the share and exchange of intellectual output of the institute.
Communities in DSpace
Select a community to browse its collections.
Recent Submissions
WII e-Newletter (winter)
(Wildlife Institute of India, Dehradun, 2025) Kolipakam, Vishnupriya; Gautam, Ritesh Kumar; Kaur, Amarjeet
WII e-Newletter (Autumn)
(Wildlife Institute of India, Dehradun, 2025) Kolipakam, Vishnupriya; Gautam, Ritesh Kumar; Kaur, Amarjeet
WII e-Newletter (summer)
(Wildlife Institute of India, Dehradun, 2025) Kolipakam, Vishnupriya; Gautam, Ritesh Kumar; Kaur, Amarjeet
Ecological and phylogenetic aspects of an Avian aerial Insectivore: The Barn Swallow in the Himalaya
(Wildlife Institute of India, Dehradun, 2026) Kaur, Amarjeet
This thesis is a first to document the ecology of a common and widespread species yet is declining in many parts of its range, the Barn Swallow (Hirundo rustica). The species breeds in the Northern Hemisphere and undertake long-distance migratory movements every year to its non-breeding grounds in Southern Hemisphere. Owing to its close association with humans – the nature of nest building in human artefacts, the Barn Swallow is a well-known human commensal species globally. Due to its widespread distribution, populations show variations in their morphological as well as genetic traits, and globally six subspecies of H. rustica are recognized, of which two are sedentary or non-migratory. Though common, this aerial insectivore is experiencing severe population declines in Canada, North America and parts of Europe with global population trend status is declining. The widespread declines in Barn Swallow populations have alarmed the scientists across the world with the urgent need for ecological monitoring and identification of region-specific drivers of decline.
In India, three out of six subspecies of Barn Swallow are reported to occur - two subspecies, H. r. rustica and H. r. gutturalis breed in Himalaya while the third H. r. tytleri is a winter visitor in Northeast India. Given the documented alarming declines across regions, population trends of Barn Swallows in India remain unknown. This formed the basis of this thesis wherein the knowledge gaps on species are addressed with three major components. First, given the absence of any population trend, eBird data - citizen-science observations was utilised to examine the species’ breeding and non-breeding distribution across the Indian subcontinent. Second, field surveys were conducted across the Himalayan region to document the breeding sites of Barn Swallows with main focus of documenting breeding ecology in the Uttarakhand Himalaya. Third, Barn Swallow populations across the Himalayan range were examined to assess morphological and genetic variations. Finally, the thesis is concluded by synthesizing ecological and evolutionary findings, while also highlighting the strong cultural relationship between Barn Swallows and the people of the Himalaya. The first objective focuses on eBird locations to document the occurrence of Barn Swallows in the Indian subcontinent. eBird platform is valuable particularly in parts of the world where long-term species monitoring programs are limited and access to ecological data remains constrained. eBird data was utilized with the objective of investigating the occurrence and seasonal movements of the Barn Swallow in the Indian Subcontinent. With five years of data (2019 – 2023), following eBird best practice criteria, checklists were filtered and considered for the analyses. Barn Swallows presence data was compiled for the Indian subcontinent region, divided into equal-area icosahedron hex grids (25 km²). For each cell, daily presence was calculated and then weighted daily mean location was calculated using the central longitude and latitude of each cell. A generalized additive model (GAM) was applied on the weighted mean daily locations for each year to model latitude and longitude separately as functions of time (Julian day). Combining the predicted latitude and longitude values from the fitted GAM, daily population-level centroids were generated. From the GAM predicted occurrence centroids, migration timing, migration speed and migration distance was calculated, and seasonal and annual variations were compared using linear regression and linear mixed models.Across five years, Barn Swallows bred at a mean latitude of 28.18°N and wintered around 16.19°N, with marked interannual variation in both breeding extent and migration timing. Spring migration began on average in late March and was faster than autumn migration (23.7 vs. 20.1 km/day), although this difference was marginal. Migration distances were similar between seasons (≈1550 km in spring; ≈1670 km in autumn). Migration timing influenced latitudinal positions, with later spring departures associated with more northerly locations and later autumn departures with more southerly positions. Weak northward shifts in migration routes and breeding latitudes were observed over time, indicating subtle directional changes in the migratory system.
This eBird analysis provides the first broad-scale synthesis of Barn Swallow migration within the Indian subcontinent, revealing that Himalayan-breeding populations consistently occupy higher latitudes during breeding and overwinter predominantly in southern India, underscoring India’s central role in Asian migratory connectivity. Migration phenology showed spring departure in late March and residence at breeding sites until late July, with faster and slightly shorter spring migration compared to autumn, consistent with optimal migration theory and monsoon-driven resource tracking. Interannual variation in timing, speed, and distance likely reflects environmental variability along migratory routes. Weak but consistent northward shifts in breeding and migratory latitudes suggest early climate-driven range adjustments that may be especially consequential in the rapidly changing Himalayan landscape. Despite limitations of citizen science data, these findings establish a critical baseline for understanding the migration ecology of Himalayan Barn Swallows and highlight the need for integrated tracking and ringing studies to resolve population-specific routes, identify key non-breeding habitats, and assess future climate and land-use impacts.The second objective focuses on documenting breeding distribution and nesting ecology of Barn Swallows in the Indian Himalayan Region. Systematic surveys across the Himalayan range from west to east axis between 2019 and 2023 (excluding two years- 2020 and 2021 of COVID-19 pandemic) were carried out. On locating a nest, nest-site characteristics and nest attributes were recorded. Systematic nest monitoring was conducted across four sites in Uttarakhand to quantify breeding parameters and nest success of Barn Swallows, with nests monitored every 5–7 days from initiation to outcome. Breeding metrics including clutch size, brood size, fledgling number, and nesting duration were estimated, and nest success was assessed using both apparent success and Mayfield nest survival estimates to account for unequal exposure times. Spatial and temporal variation in nest success was analysed using binomial generalized linear models. To examine nestling diet and prey selection, faecal samples were collected from active nests and prey remains were identified to insect order using microscopy, while aerial insect availability was quantified through sweep-net sampling along foraging transects at rural and urban sites. Diet composition and prey availability were compared across settlement types using frequency of occurrence, PERMANOVA, and NMDS based on Jaccard dissimilarity, allowing assessment of dietary differences between urban and rural habitats and evaluation of prey use relative to local insect communities.
Across the Indian Himalaya, 1,450 Barn Swallow nests were recorded between an elevation belt of 489 and 2,317 m, with a mean nesting elevation of ~1,500 m and high concentration within the mid-elevational range (1,000–2,000 m). Nesting records spanned 24.4–34.2°N and were unevenly distributed among states, with Uttarakhand contributing the majority of nests and exhibiting the broadest elevational range. Across the region, over 70–90% of nests were located inside buildings, most commonly on walls, bulb holders, and other artificial supports, with commercial structures such as shops dominating in most states. In Uttarakhand, breeding activity extended from late February to late June, with mean nest initiation around day 102 of the year and clear advancement in nest initiation, egg-laying, and fledging dates across years, particularly in 2023. Mean clutch size was 3.88 eggs, mean brood size 3.25 chicks, and successful nests fledged an average of 2.63 young, though reproductive output varied across sites. Apparent nest success was 62.2%, while Mayfield estimates indicated higher overall nest survival (mean 76.5%), reflecting differences in exposure time and daily survival rates among sites and years. Nest success varied significantly among regions but not among years, with Nainital and Bageshwar showing consistently higher success than Kempty. Diet analysis of 240 nestling faecal samples identified six insect orders, dominated by Coleoptera (96.7%) and Hymenoptera (75%), with significant differences in prey composition between rural and urban settlements and weaker spatial structuring within settlement types. Aerial insect sampling revealed distinct insect communities between rural and urban habitats, yet nestling diets differed significantly from local prey availability at both settlement and site levels, indicating selective foraging rather than passive prey use. This objective’s findings provide the first comprehensive assessment of Barn Swallow breeding ecology across the Indian Himalaya, demonstrating that the species is a widespread and regular breeder across a broad elevational range, with nesting concentrated at mid-elevations where it is likely that climatic conditions and prey availability are most favourable. The strong association with human-made structures - particularly indoor nesting in shops and traditional buildings - highlights the species’ long-standing commensal relationship with people in the region and complete dependence on human structures for nesting in the region. Spatial variation in breeding distribution and reproductive success appears to be driven by regional climate, monsoon dynamics, and local habitat quality, while the observed advancement in breeding phenology between 2019 and 2023 is consistent with climate-driven shifts documented in migratory birds globally. Dietary analyses revealed selective foraging, with nestlings fed predominantly large-bodied insects, especially Coleoptera and Hymenoptera, and clear differences between rural and urban settlements reflecting habitat-specific prey availability. The mismatch between available insects and prey consumed indicates active prey selection rather than opportunistic feeding, though reliance on faecal analysis may underrepresent soft-bodied taxa. Collectively, these findings underscore the vulnerability of Himalayan Barn Swallow populations to rapid changes in architecture, land use, and insect communities. The ongoing replacement of traditional buildings with sealed modern structures, combined with widespread declines in aerial insects, may create ecological traps where nesting opportunities persist but food resources do not. Conservation efforts in the Himalaya should therefore integrate nest-friendly architectural practices, protection of insect-rich foraging habitats, and long-term monitoring to safeguard this culturally valued and ecologically important aerial insectivore in a rapidly transforming mountain landscape.
The third objective of the thesis is aimed to fill the gap in identity and origin of Barn Swallow populations breeding in the Indian Himalayan region. Despite well-documented morphometric variation among Barn Swallow subspecies, the identity, breeding distribution, and evolutionary history of populations breeding in the Indian Himalayan region remain poorly understood. In particular, it is unknown when Barn Swallows colonized the Himalaya, how Pleistocene glacial events shaped their present-day distribution, and how or whether geographically isolated populations - such as the sedentary population in Manipur - diverged from the largely migratory Himalayan populations. Addressing this gap, the third objective of this study investigates the phylogeography of Barn Swallow populations breeding in the Indian Himalaya within a global context, integrating Indian populations with well-studied breeding populations worldwide to elucidate their evolutionary relationships, historical connectivity, and region-specific adaptations. For this objective, adult Barn Swallows were captured at breeding sites across Kashmir, Uttarakhand, North Bengal, and Manipur using mist-nets and customized butterfly nets, and standard morphometric measurements were recorded. Birds were banded, and small blood samples were collected from adults for genetic analysis. Morphometric variation among regions was examined using principal component analysis, one-way ANOVA, and post-hoc tests, with wing length used as a proxy for body size and additional regression analyses conducted to assess latitudinal trends; sexually dimorphic tail streamers were analysed separately by sex. For phylogeographic analysis, mitochondrial Cytochrome b and ND2 gene sequences were generated from blood samples, following DNA extraction using standard kits and PCR amplification with published primers. Sequences were edited, aligned, and analysed alongside global Barn Swallow subspecies sequences retrieved from GenBank. Genetic diversity was estimated, phylogenetic relationships were reconstructed using Bayesian inference in BEAST with appropriate substitution models and outgroup rooting, and haplotype relationships were visualized using median-joining networks, with genetic distances calculated under the best-fitting evolutionary model. Barn Swallow populations across the Indian breeding range showed pronounced variation in plumage, morphology, and genetic structure. Plumage colouration varied geographically, with buff-bellied birds with broken or broad breast bands dominating Uttarakhand and North Bengal, mixed white to rufous-bellied individuals with complete breast bands in Kashmir, and predominantly rufous to chestnut-orange birds with broken or complete breast bands in Manipur. Morphometric analyses of 158 adults revealed clear regional structuring, with principal component analysis separating populations primarily along a body size axis (PC1) and a bill morphology axis (PC2), together explaining 58.6% of total variance. Birds from the Srinagar Valley were significantly larger, exhibiting the greatest wing lengths, while individuals from the Imphal Valley were smallest; Himalayan populations (Uttarakhand and North Bengal) were intermediate but showed greater variability in bill traits. Sexually selected outer tail length was consistently longer in males than females, with both male and female Kashmir birds exhibiting significantly longer streamers than those from other regions. Across all populations, wing length, tarsus length, body mass, and head length increased significantly with latitude, indicating strong latitudinal clines in body size.Phylogeographic analyses based on mitochondrial Cyt b and ND2 genes revealed two genetically distinct Barn Swallow lineages within India. All samples from Kashmir, Uttarakhand, and North Bengal clustered into a well-supported and genetically distinct Himalayan clade, whereas samples from Manipur, along with two individuals from Uttarakhand, grouped with the East Asian subspecies Hirundo rustica gutturalis. Both Bayesian phylogenetic reconstruction and haplotype network analyses consistently supported this deep genetic separation, indicating that Himalayan Barn Swallow populations represent a distinct evolutionary lineage, clearly differentiated from other recognized subspecies across the species’ global range.This study demonstrates strong geographic structuring in morphology and genetics of Barn Swallows across the Indian Himalayan region, shaped by latitude, ecology, and historical biogeography. Birds breeding at higher latitudes in Kashmir were consistently larger, with longer wings and exaggerated male tail streamers, conforming to well-established latitudinal size clines and suggesting adaptation to colder climates, migratory demands, or flight efficiency. Central Himalayan populations (Uttarakhand and North Bengal) showed intermediate morphology with greater trait variability, indicating partial phenotypic cohesion along the Himalayan axis, potentially constrained by geographic barriers such as the Pir Panjal range. In contrast, the newly documented resident breeding population in Manipur exhibited distinct plumage and smaller body size, with morphometric traits that do not align cleanly with described subspecies, instead appearing intermediate between H. r. tytleri and H. r. erythrogaster. This challenges traditional subspecies assignments in South and Southeast Asia and highlights unresolved complexity in the region’s biogeographic history. Phylogeographic analyses revealed two well-defined mitochondrial lineages within India: a distinct Himalayan clade encompassing Kashmir, Uttarakhand, and North Bengal, and an eastern lineage aligned with H. r. gutturalis that includes all Manipur samples and a small subset from Uttarakhand, suggesting secondary contact or admixture. The concordance between morphometric differentiation and genetic structure indicates that geographic isolation, local adaptation, and sexual selection may jointly reinforce divergence despite the species’ high dispersal ability. The Manipur population may have arisen through secondary colonization and introgression or through a shift from migratory to sedentary breeding within a former wintering range, underscoring the Barn Swallow’s capacity for rapid evolutionary and behavioural change. While these patterns point to the Himalaya as an important axis of divergence, the Himalayan lineage is best viewed as an incipient evolutionary or management unit rather than a fully differentiated subspecies, emphasizing the need for genome-wide data and migratory tracking to resolve evolutionary status and inform conservation in this climatically sensitive region.
Thie last chapter discusses on Barn Swallows as one of the world’s most successful avian commensals, whose close association with humans emerged relatively recently alongside permanent settlements during the Holocene. Across cultures, their reliance on human-made structures for nesting has fostered deep symbolic, religious, and emotional connections, particularly in breeding regions. In the Indian Himalaya, where Barn Swallows are summer breeders nesting predominantly inside houses and shops between 1000–2000 m elevation, these cultural relationships had not previously been documented. By combining large-scale surveys with ethnographic-style interviews, this study demonstrates that Barn Swallows occupy a unique socio-ecological niche in the Himalaya, where their breeding ecology is inseparable from human tolerance, daily routines, and traditional belief systems.Survey results across the Himalayan region revealed overwhelmingly positive perceptions of Barn Swallows, reflected in vernacular names that associate the species with gods, prosperity, and domestic well-being. In Uttarakhand, residents reported nesting histories extending back several decades to over a century, strong nest-site fidelity, and widespread nest protection practices, including deliberate avoidance of disturbance. Despite threats such as competition with House Sparrows, nestling mortality from ceiling fans, and predation by domestic animals, human tolerance remained high. The COVID-19 lockdown provided a natural experiment demonstrating the strength of this relationship: even when shops were closed, many owners actively ensured access for swallows by modifying shutters or maintaining openings, allowing most nests to persist. These findings highlight cultural values as an unrecognized yet critical buffer supporting Barn Swallow breeding success in human-dominated Himalayan landscapes.However, the findings of the chapter also underscore emerging vulnerabilities. Rapid urbanisation, architectural modernisation, tourism pressure, and changing hygiene norms threaten the availability of traditional nest sites and may erode long-standing cultural tolerance. While positive perceptions remain deeply rooted across much of the Himalaya, early signs of shifting attitudes mirror trends already documented in parts of East Asia, where modernization has led to nest exclusion. Given the Barn Swallow’s near-total dependence on human structures, the persistence of culturally mediated coexistence may be as important as ecological factors for its future in the region. This chapter therefore emphasizes that conserving Barn Swallows in the Himalaya requires not only habitat and insect prey management, but also the recognition, preservation, and integration of traditional cultural values into conservation and development planning. Overall, my thesis provides the first integrated ecological, evolutionary, and socio-cultural assessment of Barn Swallows in the Indian Himalayan region, revealing the Himalaya as a key axis of divergence, connectivity, and human–wildlife coexistence within the species’ Asian range. By combining citizen-science–derived migration analyses, extensive field-based breeding ecology, detailed dietary and reproductive assessments, phylogeographic and morphometric analyses, and cultural perspectives, the study demonstrates that Himalayan Barn Swallow populations are shaped jointly by climatic gradients, historical biogeography, selective pressures linked to migration and reproduction, and an unusually strong dependence on human tolerance. The identification of a distinct Himalayan genetic lineage, the reporting of a resident breeding population in Manipur, evidence for climate-linked phenological shifts, and the documentation of culturally mediated nest persistence together underscore the species’ capacity for rapid ecological and behavioural adaptation, but also its vulnerability to accelerating environmental change. Collectively, these findings establish a critical baseline for monitoring population trajectories in India, challenge simplified subspecies boundaries in Asia, and highlight that effective conservation of this declining aerial insectivore in the Himalaya will require integrative approaches that link evolutionary history, migration ecology, insect prey documentation, urban architecture-sensitive planning, and the preservation of traditional human values that have long enabled coexistence of Barn Swallows with humans in this complex mountain landscape of the Himalaya.
Population dynamics and breeding habitat use by colonial waterbirds nesting at the Kokkare-Bellur Community Reserve, Southern Karnataka
(Wildlife Institute of India, Dehradun, 2026) Mahapatra, Aksheeta; Kumar, R. Suresh