Study highlights decline in over-summering shorebirds along Ramanathapuram coast

Study emphasizes need for conservation to protect over-summering shorebirds in Tamil Nadu facing habitat degradation and decline.

A recent study by researchers from the Centre of Advanced Study in Marine Biology, Annamalai University, has highlighted the need for targeted conservation efforts to protect over-summering shorebird populations along the southeastern coast of Tamil Nadu, as many species face decline due to habitat degradation and lack of protection. 

Over-summering of shorebirds occurs when certain migratory shorebird species stay on their non-breeding grounds during the summer instead of flying to their breeding areas, often for one or more years. This behaviour is influenced by environmental, physiological, and ecological factors. Often, these birds are either sexually immature or are avoiding the risks associated with migration.

The occurrence and timely migration of shorebirds are closely tied to the quality of their stop-over and wintering sites. The study by wildlife biologists H. Byju, H. Maitreyi, N. Raveendran, and S. Ravichandran, published in the Journal of Threatened Taxa, explored the over-summering behaviour of migratory shorebirds along Manoli, Dhanushkodi, Valinokkam, and Pillaimadam in Ramanathapuram district from 2017 to 2023. 

A total of 13 over-summering species were documented from the four sites. Of the 13 species observed, 10 — lesser sand plover, greater sand plover, grey plover, whimbrel, Eurasian curlew, common greenshank, common redshank, little stint, and ruddy turnstone — were found at all four sites. In contrast, the black-tailed godwit, bar-tailed godwit, and common sandpiper were only recorded at the Dhanushkodi lagoon in 2023.

In Valinokkam, a man-made lagoon, the decline of eight over-summering shorebird species during the study suggested long-term issues like habitat degradation or reduced prey availability. Pillaimadam showed a worrying trend of significant declines in all over-summering shorebird populations during the study, highlighting the need for focused conservation efforts. Notably, both of these lagoons are unprotected areas.

“The decline in over-summering shorebird abundance across all sites suggests an ongoing habitat degradation issue, as reflected by the overall global decline in shorebird populations, particularly within the Central Asian flyway including regions like Dhanushkodi,” the study noted.

Speaking to The Hindu, Mr. Byju expressed concerns about Dhanushkodi, a significant pilgrimage site, where visitors irresponsibly discard clothes and plastic waste. This pollution is shrinking the foraging area for birds, potentially causing some to relocate, though it won’t eliminate the entire population.