Karanji Lake is a 90-hectare urban lake on the southeastern edge of the zoo grounds, managed as a bird sanctuary. It is home to painted storks, purple herons, cormorants, egrets, and — in winter — migratory species including bar-headed geese, which fly directly over the Himalayas on their migration from Central Asia. A walkway runs along the bund (embankment) and a butterfly park occupies the southern end.
The lake is best in the early morning or late afternoon when light is good for birdwatching. It is much quieter than the zoo and offers a peaceful hour of waterbird watching on the edge of the city. Entry is included in the zoo ticket if you visit both together.