A survey on lesser flamingos by the Conservation Action Trust (CAT) since 2006 has found a decline in the number of the pink-feathered birds flying to their favourite spots in the Thane creek.
According to the survey, the dip has been quite marked at Airoli and Sewri. While the flamingos spotted in Airoli in 2006 were an estimated 6,000, the number dipped to about 1,000 last year. Similarly, about 8,000 flamingos dotted the Sewri mudflats in 2006 but their estimated numbers decreased to an estimated 4,000 in 2011. However, the number of migratory birds has remained steady at about 100 at Vashi creek through the last five years.
Environmentalists said the Thane Creek – designated as an Important Bird Area by the Bombay Natural History Society – has been under constant threat from slum encroachments, discharge of effluents from industrial units in the Thane-Belapur Industrial Complex, reclamation for industrial projects and debris dumping.
“Though the arrival of flamingos to Mumbai has been delayed, there has also been an overall decline in their numbers. However, we cannot pinpoint reasons for the dip in numbers,” said Debi Goenka, founder of CAT, adding that industrial pollution in the creek will affect marine life, which the birds feed on.
Goenka added, “Water in the Thane creek is also getting shallow because of siltation. Though a little shallow water is good for mangroves and flamingos, further siltation will be detrimental for the birds.”
Sporting binoculars, between November and February, CAT volunteers spend most of their weekends counting the flamingo’s estimated population at the three spots. Volunteers begin by counting a block of 10 or 100 flamingos as one unit and subsequently progress to draw an estimation of the entire flock during the season.
Since 1990, lesser flamingos — scientifically known as Phoenicopterus minor — have been visiting the Mumbai coast and adjoining Thane creek. Every year, thousands of flamingos fly from the Rann of Kutch region in Gujarat to the mudflats and wetlands, which serve as feeding grounds and shelter to them.
“The number of flamingos has been fluctuating. They could be scattering to other marshy and swamp areas,” said naturalist Sunjoy Monga. “Urbanisation, infrastructure development and loss of wetlands could also result in diverting the birds to a different location.”