CHENNAI: A seven-year migration trail traced through a single bird has drawn attention to the ecologically sensitive Nemmeli coastal wetlands, now facing mounting threats, including the proposed Mamallan reservoir project.
In early March, volunteers from Suzhal Arivom documented a ringed adult male Montagu’s Harrier at Nemmeli, a coastal grassland-wetland complex along the East Coast Road. The bird was later confirmed to have been ringed as a juvenile in Rajasthan in 2019 by researchers at the Ashoka Trust for Research in Ecology and the Environment (ATREE), establishing a rare and verifiable long-distance migration link.
“This is not just a sighting; it reflects continuity,” said Arjun Kannan of ATREE’s HarrierWatch programme. “Harriers exhibit strong site fidelity during winter. The repeated return of this individual suggests that Nemmeli is a critical habitat for the species.”
Field observations over a week recorded the bird engaging in hunting, roosting and pairing behaviour, indicating that the site functions as a wintering ground rather than a transient stopover. Volunteers also sighted Pallid Harriers, Western Marsh Harriers, Peregrine Falcons and Red-necked Falcons, underscoring the area’s significance as a raptor habitat.
According to a field report by Suzhal Arivom, the Nemmeli complex has supported multiple migratory raptor species over two consecutive winters, with activity recorded throughout the day. “This pattern is characteristic of an established wintering habitat,” the report noted.
The wetlands also support biodiversity along the Central Asian Flyway. Migratory waterfowl such as pintails, garganey, shovelers and sandpipers frequent the site, while species like the Demoiselle Crane and Bar-headed Goose have also been recorded. The landscape’s mix of grassland, shallow wetlands and salt flats provides feeding and refuge grounds.
D Madhan, a biomimetics researcher associated with Suzhal Arivom, said the ecological significance extends beyond avifauna. “The ecosystem supports a range of lesser-studied marine and brackish organisms. Its loss would mean the disappearance of undocumented ecological knowledge,” he said.
Conservationists, however, point out that the site lacks formal protection and faces increasing pressure from coastal development. Real estate expansion along the East Coast Road, waste dumping and habitat fragmentation continue to degrade the area.
Concerns have intensified over the proposed Mamallan reservoir project, which could alter local hydrology and land-use patterns. “Changes to such habitats directly affect species that depend on them,” said M Yuvan of the Madras Naturalist Society.
The Tamil Nadu Raptor Research Foundation (TNRRF), established in 2025, has identified coastal wetlands as priority habitats. Experts say Nemmeli presents an opportunity for early intervention. “There is emerging evidence of ecological importance,” a Suzhal Arivom volunteer said.
Researchers have called for baseline ecological assessments, habitat mapping and consideration of the site under conservation frameworks such as Biodiversity Heritage Sites or Conservation Reserves.