THOOTHUKUDI: Researchers observed breeding colonies of six bird species including the Brown Noddy and five tern species at the sand bars of Adam's Bridge, also called the Ram Setu, along the Indian Maritime Boundary Line (IMBL). The Adam's Bridge, which is about 8 km southeast of Arichalmunai point in Rameswaram, consists of sand banks in the Gulf of Mannar Marine Biosphere Reserve that intermittently connects Rameswaram and Sri Lanka.
The study ‘Breeding tern colonies on the sandbars of Adam's Bridge, India:
new records and significance’ was published on March 26 in the 'Journal of Threatened Taxa'. It documents the breeding colonies of five tern species including the Bridled Tern, Saunder's Tern, Little Tern, Greater Crested Tern and Roseate Tern in the sandbars of Adam's Bridge.
To study the terns' breeding activity, five teams of researchers accompanied by personnel from the Wildlife Division of Gulf of Mannar Biosphere Reserve, surveyed the sand bars between June and August in 2024. They managed to record 16 waterbird species.
Senior Researcher H Byju and Research Scholar H Maitreyi of the Centre of Advanced Study in Marine Biology; Birder and Founder of Iragukal Amritha Nature Trust N Raveendran and Biologist of Gulf of Mannar Biosphere Reserve DA Marshal authored the paper.
Lead author H Byju told TNIE that breeding was confined to sandbar III and VII, while the largest colony of breeding terns was sighted at sandbar VII.
Breeding tern colonies on the sandbars of Adam's Bridge
According to the study, sandbar III had a colony of 250 to 300 nests of the Greater Crested Tern. Over 12,000 Greater Crested Terns, 600 Bridled Terns, 400 Roseate Terns, 220 Saundern's Terns and 80 Little Terns were recorded in sandbar VII. The sandbar III and VII was populated by 4,000 breeding tern pairs, which are the largest mixed breeding colonies in the southern peninsula of India, the study highlighted.
Observation of Brown Noddy
Another research paper published on March 26, comprising the same set of researchers including Professor S Ravichandran Centre of Advanced Study in Marine Biology, has confirmed the first record of Brown Noddy breeding colonies at Adam's Bridge.
Brown Noddy (Anous stolidus), is a tropical and subtropical seabird, previously known to have breeding colonies in Maldives and Cherbaniani and Pitti islands of Lakshadweep.
Byju said that the breeding colonies of Brown Noddy were spotted at sandbank VII of the Adam's Bridge in July 2024.
"The nests were found in sympatric association with terns, especially a few Bridled Terns and thousands of Greater Crested Terns breeding on the sandbar," he said.
"Previously Brown Noddy was noted as a migratory bird, originating from Lakshadweep Islands. But the present finding that the breeding ground is near to Rameswaran may lead to the consideration that it is a resident bird,” he said.
Seeking conservation and mitigation efforts by wildlife and concerned security agencies, the researchers said the eggs of terns are poached by local fishermen in Rameswaram for consumption. Poachers from Sri Lanka transgress into the Indian sandbar VII to collect eggs and birds using speed boats. The remains of fishing gear, plastic bottles, clothes, and household waste indicate man-made pollution, he said.
The chain of sandbanks being a safe haven and breeding ground for the pelagic birds, along the IMBL requires conservation plans to assuage dangers of climate change and poachers, the researchers appealed.