CHENNAI: Spread across 37,733 hectares on the Coromandel Coast in the Nagapattinam district, the Point Calimere Wildlife and Bird Sanctuary – declared a Ramsar site in 2002 for its ecological importance – every year takes thousands of species of migratory birds under its wings. A salient coastal ecosystem known for its diverse habitats, the sanctuary, which includes the Great Vedaranyam Swamp and Talaignayar Reserve, has been a keystone in the country’s conservation efforts since its establishment in 1967.
Although identified with hosting the Greater Flamingo, which arrives to feed in the brackish waters of the swamp, the sanctuary is a vital wintering ground for sundry other migratory birds from Siberia, Central Asia, and the Himalayas. Annually, over the Central Asian Flyway (CAF) – comprising 29 countries, including Iraq, Kuwait, Qatar, Kyrgyzstan, Nepal, India, Bhutan, Myanmar and Maldives – migratory birds take the non-stop haul from the Arctic and European regions during winter in South Asia, and reach the coastal swamps in Point Calimere between November and March. These birds follow specific flying patterns, engage in unique nesting and foraging behaviours, and play a crucial role in maintaining ecological balance. Some birds, such as the Bar-headed Goose, are known to fly over the Himalayas to reach Tamil Nadu’s lakes. Other notable species arriving at the sanctuary include the Black-tailed Godwit, Eurasian Curlew, Spot-billed Pelican, Northern Pintail, Common Teal, Garganey, Grey Plover, Ruddy Turnstone, and Whimbrel.
The area’s unique mangrove ecosystem serves as a breeding ground for several fish species, supporting the livelihood of local fishing communities. The saline mudflats and freshwater pools provide an ideal habitat for crustaceans and mollusks, attracting waders and shorebirds.
Despite being a crucial ecological zone, encroachment, industrialisation, poaching, and cattle grazing endanger Point Calimere’s high biodiversity. Many of the migratory birds also face habitat loss, pollution, and climate change threats. The Great Vedaranyam Swamp, an integral part of this ecosystem, is under constant pressure due to land conversion and pollution. Illegal fishing activities and unregulated tourism have further impacted the sanctuary’s delicate ecological balance. The Bombay Natural History Society (BNHS) has set up a Bird Migration Study Centre at the sanctuary, working towards conservation and spreading awareness among the local communities. The initiative has helped convert former bird trappers into conservationists, reducing hunting activities in the region.
Point Calimere’s climate, influenced by the northeast and southwest monsoons, creates a dynamic environment that supports diverse habitats. Five freshwater channels provide nutrients essential to sustaining the rich biodiversity. "However, disruptions in water flow due to human activities have degraded habitats, leading to fluctuations in bird populations. Climate change, particularly rising sea levels and storm surges, poses a long-term threat," said a renowned ornithologist and a former BNHS deputy director.
Over the five decades, the sanctuary has witnessed historical events that shaped its landscape. During the 2004 Indian Ocean tsunami, seawater flooded the area, submerging large portions of the sanctuary. While the impact on wildlife was minimal, surrounding human settlements suffered significant losses. Conservationists emphasise the need to maintain natural barriers such as mangroves to mitigate future disasters.
To enhance conservation efforts, experts suggest integrating the swamp and the adjoining Muthupet mangrove region into one protected area. Stricter regulations on industrial effluents, sustainable tourism, and habitat restoration are crucial to maintaining its ecological balance. Long-term studies on bird migration patterns, habitat changes, and climate impact, along with wetland restoration, mangrove afforestation, and new buffer zones, are key in securing the sanctuary’s future, experts said.
Supriya Sahu, Additional Chief Secretary, Environment, Forests and Climate Change Department, says the state, in the last few years, has taken several measures to protect its wetlands and give them legal status. "Chief Minister M K Stalin launched the TN Wetlands Mission, and we managed to increase the number of Ramsar sites from 1 to 20 in a short span. We understand the migratory pattern is dynamic and there are shifts noticed due to various factors. The key is to undertake long-term monitoring and build robust baseline data. We have just completed our annual synchronised bird census, and data is being analysed," she said.
Birds of diverse feathers
Besides Point Calimere, Vedanthangal Bird Sanctuary and Karaivetti Bird Sanctuary provide crucial nesting sites for migratory birds, which adopt various nesting and foraging strategies. While wading birds, such as flamingos and herons, fish in shallow water, diving birds like cormorants plunge into the water to catch prey, and ground feeders, such as the Eurasian Curlew and sandpipers, search for insects and worms in mudflats.
In the past decade, a new record of the Chinese Pond Heron was made in Kelambakkam, marking the first sighting in Tamil Nadu. The Isabelline Wheatear was observed in Tamil Nadu for the first time, suggesting the expansion of its range. Affected by habitat loss in breeding and wintering grounds, Spoon-billed Sandpiper – once recorded in Point Calimere – has not been sighted in recent years. The rediscovery of the Chalazodes Bubble-nest Frog in Kalakkad-Mundanthurai region highlights the importance of conserving wetland habitats shared by amphibians and migratory birds.
Many migratory birds that visit the state are listed under various threat categories by the International Union for Conservation of Nature (IUCN). The White-rumped Vulture has seen a drastic population decline due to habitat destruction and poisoning. The Long-billed Vulture is affected by diclofenac poisoning and the loss of nesting trees. The Egyptian Vulture is endangered due to poisoning and food scarcity. However, due to several conservation measures the vulture population is bouncing back in Tamil Nadu.
Some birds are classified as “near threatened”. The Spot-billed Pelican, although recovering, still faces habitat-related threats. The Oriental Darter is declining due to pollution and habitat destruction. The Black-headed Ibis is threatened by wetland pollution. Tamil Nadu’s wetlands and forests are under pressure from urbanisation, agriculture, pollution, and climate change. Industrial and agricultural pollutants threaten water quality in bird habitats. Some birds face threats from illegal hunting and human disturbances.
Montane grasslands
Whilst the low headlands along the Coromandel Coast face threats in every way, a remote, ecologically rich plateau at an altitude of 1,800 metres from the sea level offers a geographical respite for the migratory birds visiting the state. Grass Hills, located in the southeastern part of the Indira Gandhi (Anamalai) Wildlife Sanctuary in Tamil Nadu, is a significant haven for both migratory and endemic birds. Spanning approximately 108 square kilometres, the plateau is contiguous with Eravikulam National Park in Kerala, forming a critical part of the Western Ghats ecosystem. This unique landscape is characterised by montane forests, rolling grasslands, and steep cliffs, making it an ideal habitat for the 300 bird species, ranging from threatened to wintering birds, documented in the area. The Alpine Swift and Brown-backed Needletail are among the notable visitors, taking advantage of the plateau’s high-altitude air currents for feeding. The Mountain Imperial-pigeon and Oriental Dollarbird also frequent the region during migration.
Among the most prominent endemic birds found here is the Nilgiri Pipit, which thrives in the grasslands, alongside the Indian Broad-tailed Grass-warbler. Other vulnerable species include the Nilgiri Wood-pigeon and Great Pied Hornbill, both are frequently spotted in the montane forests surrounding the plateau.
T R Shankar Raman from Nature Conservation Foundation said, “Grass Hills is also home to an impressive array of birds of prey, including the Black Eagle, Crested Goshawk, Rufous-bellied Eagle, Jerdon’s Baza, and Mountain Hawk-eagle. These raptors play a crucial role in maintaining the ecological balance of the region, preying on small mammals and birds that inhabit the grasslands and forests.”
The plateau is particularly known for its diversity of hornbills, with the Malabar Pied Hornbill and Malabar Grey Hornbill being notable residents. The dense canopy of the montane forests provides an ideal environment for these fruit-eating birds, which aid in seed dispersal and forest regeneration. Another significant inhabitant of these forests is the White-bellied Treepie, a species endemic to the Western Ghats and an indicator of healthy forest ecosystems.