Each year, a pink cloud sweeps over Bombay Bay in November, at the end of the monsoon season. After the mating season, spent in the Kutch Salt Desert in the north-east of the country, flamingos return to Bombay as soon as the chicks can fly. For six months, the east side of the city with 18 million inhabitants is invaded by these migratory birds. But this year, it is not the usual 40,000 birds that migrated to Bombay, but 120,000 specimens.
A population growth that could be explained by a surprising factor: the rejection of highly polluted wastewater from the city would encourage the development of a type of blue-green algae whose flamingos are very fond of .
In this part of the city, factory chimneys, high-voltage cables and fishermen's nets are all threats to flamingos. And yet, despite some tragic deaths, they thrive, their feet in the waters full of dyes and heavy metals rejected by the textile factories that line the river. Flamboyance (flocks of flamingos) have migrated to the northern area of Thane Creek (a few kilometers north of their usual resort of Sewri) where there is a water treatment plant, which discharges many pollutants in the river.
Birds have always been part of an ecosystem that operates cyclically: they eat algae and shrimp, and their excrement is used as fertilizer to grow the mangrove, which prevents the rise of water, still low enough for the animals arise and can eat in the mud. The mangrove also filters heavy metals in the water. But this balance is in danger.
New area for a new life
The construction of the Mumbai-Trans-Harbor-Link (MTHL), a 22-kilometer sea bridge that will connect the city center to the city's future new airport, has destroyed flamingo habitat. The area of Sewri, where they had their habits, was ratiboisée to accommodate construction equipment, and 40% of the mangrove has disappeared in the last ten years. In October, researchers at the Bombay Natural History Society (BNHS) launched a 10-year observation mission to try to understand the evolution of flamingo populations in the city, and the impact of the man on their habitat.
Libé Labo Infographic
Forced to react, authorities created a protected area, the Thane Creek Flamingo Sanctuary. The area is 17 square kilometers (1,700 ha), plus a 10-kilometer buffer zone around the sanctuary, limiting human activity so as not to disturb the birds. Fishermen who find themselves unemployed are converted into tourism and take a boat ornithologists or curious to observe flamingos from the sea.
If the flamingo population, now more protected from human activities, continues to reproduce and thrive, not sure there is room and food for everyone. And if the flamingos disappear, the entire ecosystem of the bay would be disturbed. Without them, the mangrove is likely to disappear, and with it the massive absorption of CO2 it allows, and makes a little more livable one of the most polluted megacities in the world.