Every year in early summer, a number of flamingoes (or flamingos) migrate to this dirty, marshy area called Sewri near Mumbai. Sewri is next to the Arabian Sea and the flamingoes flock to the "beach" which is exposed as the tides recede to feast on the fish and other seafood left behind by the sea.
With two friends in tow, I visited Sewri, on March 21st, 2009. We reached there around 8 A.M. just as the tide had started receding. There were scores of flamingoes, but we also spotted a lot of other birds: kingfishers, curlews, seagulls, sandpipers, herons, kites, and night herons. Unfortunately we couldn't get close to the flamingoes. There is no way you can enter the marsh unless you are willing to wade in waist-deep mud. After the events of 26/11, boats are strictly prohibited and a police outpost keeps watch on all visitors.
If you are planning a visit, do carry good binoculars. Do visit, it is an interesting experience. Make haste as the number of visiting flamingoes is steadily going down every year.