The sleepy silence of Purbasthali is broken from early December every year with the arrival of feathered friends from halfway across the world. The Ox Bow Lake formed from the mighty Ganges caresses past villages like Chupi and Kasthashali to become home to thousands of migratory birds. The crystal clear waters of the 9 km long channel of the Ox Bow Lake and the surrounding fruit orchards and farmlands harbour more than 70 species of local and migratory birds. The Ox Bow lake covers an area of almost 3.5 sq. kms and encloses an islet with three villages. Bird watching in the lake is done in local country boats and the boatmen help the guests to spot the birds.
The lake has a narrow channel connecting the Ganges and hence has a permanent source of water pouring into the lake. The rich alluvial soil of Ganges basin and abundance of rainfall has endowed the Purbasthali region with an overdose of greenery. Hence an intense agriculture is practiced here with crops like maize, rice, corn, mustard, jute, potato and different types of vegetables, fruits and flowers growing throughout the year.