Seasonal variations in wetland bird assemblages: A case study from Dighal wetlands in Haryana, India

Abstract The Dighal wetlands, designated an important bird area (IBA) in Haryana, India, serve as vital ecosystems, and offer suitable habitats and sustenance for a diverse array of resident and migratory wetland birds. Avian surveys were conducted by adopting direct observations and point count methods between April 2021 and March 2023, aimed to document the assembly of wetland birds within this IBA site. A total of 90 species of wetland birds distributed across 12 orders, 23 families and 62 genera were identified. The Charadriiformes order exhibited the highest species richness (24) followed by Anseriformes (19). Anatidae with 19 species emerged as the most diverse family, constituting 21% of the total species identified. The study revealed the seasonal dynamics, with 33.3% resident, 62.2% winter migrants, and 4.5% summer migrants. Notably, winter season recorded the highest species richness and population abundance. The study underscores significant differences in species richness, abundance, diversity, and evenness in both seasons of the first and second year. Moreover, the study unveiled non-significant distinctions in richness, abundance, diversity and evenness of wetland birds across these years (2021–2022 and 2022–2023). Among the recorded avifauna, three species are listed as Vulnerable and four species as Near Threatened in the IUCN Red List (2024). Additionally, two species are listed in CITES Appendix I, while six species were included in CITES Appendix II. Furthermore, ten species were listed in Schedule I of WPA (2022). Dighal wetlands played a crucial role in supporting 30 species of wetland birds experiencing a decreasing global population trend. The prevalence of a significant number of wetland bird migrants and wetland bird species of global conservation importance underlines the urgent need for robust conservation efforts to protect both the wetland birds and their habitats.