The present study was conducted to determine the winter avifauna diversity of the Bakreswar Reservoir, Birbhum district, West Bengal from November 2017 to February 2021 using point count and opportunistic spotting. A total of 174 species of birds belonging to 18 orders, 47 families and 115 genera were noted during the study of which the family Anatidae was the most dominant family with 21 species, followed by the Accipitridae with 19 species, and the Motacillidae and Ardeidae with 10 species each. The Lesser whistling teal Dendrocygna javanica, Red-crested pochard Netta rufina and Bar-headed goose Anser indicus were the most abundant species during the winter months. Four Vulnerable species and five Near Threatened species were also recorded in the study area. Various diversity indices indicated that the species assemblage in 2019–2020 was more diverse than other years. Some species, such as the Common shelduck Tadorna tadorna (Linnaeus, 1758), Swinhoe’s minivet Pericrocotus cantonensis Swinhoe, 1861, Eurasian sparrowhawk Accipiter nisus (Linnaeus, 1758), Pallas’ gull Ichthyaetus ichthyaetus (Pallas, 1773), Black-headed gull Chroicocephalus ridibundus (Linnaeus, 1766), Hen harrier Circus cyaneus (Linnaeus, 1766) and Bonelii’s eagle Aquilla fasciata Vieillot, 1822, are recorded for the first time from this region. Various threats like habitat destruction, habitat degradation and hunting of migratory and threatened birds pose the major problems in the study location.