ABSTRACT
This study investigates the spatial and behavioural associations between Painted Storks (Mycteria leucocephala) and Indian Cormorants (Phalacrocorax fuscicollis) within two urban wetland sites in Kolkata, India: Santragachi Jheel and Rabindra Sarobar Lake. Field surveys were conducted over two consecutive years using binoculars and digital cameras to monitor nesting behaviour, tree use, and seasonal abundance. Both species were observed nesting on the same trees, cohabiting in mixed-species colonies, particularly during winter and summer, with minimal interspecific conflict and no evidence of competition for nesting space or food. To test hypotheses regarding spatial nesting association (H1), behavioural shifts in mixed colonies (H2), and potential mutual benefits (H3), seasonal data were analysed using non-parametric Kruskal–Wallis tests. Although visual trends indicated higher abundance and nesting activity in winter, statistical analysis did not confirm significant seasonal differences (p > 0.05), likely due to limited sample size. Nonetheless, qualitative observations support the presence of a commensal or facilitative relationship, wherein both species benefit from shared predator vigilance and optimal nesting sites. This study contributes to the understanding of interspecific nesting ecology in tropical urban wetlands and highlights the ecological value of protected urban lakes as breeding grounds for large waterbirds. Further multi-year, multi-site studies are recommended to validate these preliminary findings.
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