Avifauna of Nijhum Dweep National Park in Bangladesh, an East Asian-Australasian Flyway Network Site and Important Bird Area in the World’s Largest River Delta

Creating a species checklist for a given area or ecosystem is a prerequisite for ecological studies, biodiversity assessments, conservation reports, and other analyses related to animal diversity. Nijhum Dweep National Park in Bangladesh is an East Asian–Australasian Flyway Network Site for migratory waterbirds and an Important Bird and Biodiversity Area in the Ganges–Brahmaputra–Meghna delta. Despite its global importance for bird conservation, a systematic avifaunal checklist of the park was previously unavailable. Here, we present a comprehensive checklist based on surveys conducted from 2015 to 2020. We spent 86 days counting high-tide roosts in the mudflats and brackish marshes for waterbirds, and 40 days conducting strip-transect surveys in mangroves for inland bird species. We documented 161 bird species, including 20 new records for the park. Our checklist represents approximately 23% of all bird species recorded in Bangladesh. Of these, 50 species were passerines and 111 were non-passerines. Resident species comprised the majority (52%), with migratory species accounting for 48%. Notably, sixteen species on the list are of international conservation concern. The park is one of the last strongholds for non-breeding Indian Skimmers Rynchops albicollis, an Endangered species, and is also an important non-breeding site for the Critically Endangered Spoon-billed Sandpiper Calidris pygmaea and the Endangered Nordmann’s Greenshank Tringa guttifer. Our findings reaffirm the park’s significance as an Important Bird and Biodiversity Area and provide valuable baseline information for monitoring and conserving avian diversity in this protected area.