Composition, diversity and foraging guilds of avifauna in a suburban area of southern West Bengal, India

Avian communities are very good indicators of any ecosystem. Despite the alarming consequences of rapid urbanization, studies of avian diversity in the human-dominated landscapes of India are very few. Therefore, we studied the avian assemblage of Bongaon in southern West Bengal, India, a suburban area whose avifauna has thus far remained undocumented. Bird surveys were carried out from June 2015 to May 2016, following the fixed-radius (25 m) point count method together with opportunistic observations. We recorded 119 avian species belonging to 53 families. Ardeidae was the most diverse avian family in the study area (RDi value = 5.882). Among the recorded avifauna, 89 species were resident, 26 species were winter visitors, three species were summer visitors, and one species was a passage migrant. Species richness of the resident and passage migrant species did not vary seasonally, while the winter and summer visitors displayed significant seasonal variation. In this suburban area, the species richness of feeding guilds varied significantly. Most birds were insectivorous (41.2%), followed by carnivorous (24.4%), omnivorous (18.5%), granivorous (7.6%), frugivorous (3.4%), nectarivorous (3.4%) and herbivorous species (1.7%). Maximum species richness was recorded in November and minimum species richness in July. Black-headed Ibis Threskiornis melanocephalus and Alexandrine Parakeet Psittacula eupatria are two near-threatened species found in this region. Interestingly, six species having a globally declining trend are still very common in the study area. Long-term studies are required to monitor any change in the avian communities of this suburban landscape resulting from urbanization.