Crab-plover, the only shore bird that lays eggs in self-excavated burrows on sandbanks, might soon be called a resident species of the Indian subcontinent as their unique breeding sites have been recorded at Great Vedaranyam Swamp near Point Calimere, Tamil Nadu.
The presence of five burrow nests of the crab-loving shore bird recorded at an islet near Siruthalaikkadu of Great Vedaranyam Swamp in August gained significance as the species was initially believed to only breed in the islands of the African east coast, the Persian Gulf, and the southern coasts of the Arabian Peninsula from June to August.
Crab-plover (Dromas ardeola) is considered a winter visitor to Pakistan, peninsular India, the Andaman and Nicobar Islands, Lakshadweep, northern Sri Lanka, and the Maldives, and a vagrant to Bangladesh, said Byju H., a researcher with the Centre of Advanced Sciences in Marine Biology, Annamalai University, about the finding.
A paper on the first evidence of crab-plovers breeding in the Indian subcontinent, co-authored by Mr. Byju; Aarif K.M. from Czech University of Life Sciences, Prague; and N. Raveendran of Iragukal Amritha Nature Trust, Madurai, was published in a recent issue of the Journal of Threatened Taxa.
The researchers got a hint that crab-plovers could be breeding on Indian sandbanks at a talk presented by Guyomini Panagoda of University of Colombo about the Central Asian Flyway (CAF) and bird migratory pathways in Sri Lanka in November 2022.
The study mentioned five crab-plovers that were satellite-tagged and colour-banded for migratory studies. One of the green-flagged (international colour coding used for Sri Lanka for migratory studies in CAF) birds had stayed in the Point Calimere region between June and August 2022, after moving from Sri Lanka. An attempt made by the Bombay Natural History Society team to trace the same bird turned out to be futile.
“The same male bird was spotted with a juvenile on August 30, 2022 at Talai Mannar in Sri Lanka, giving us a hint about crab-plovers potentially breeding in the Palk Bay region of Point Calimere. Field visits were conducted in the area for three months from June to August. The five burrow nests of crab-plovers in an islet near Siruthalaikkadu were found on August 8, 2023,” he said.
According to Mr. Byju, Great Vedaranyam Swamp is abundant with mudskippers and crabs, the favourite prey species of crab-plovers. “This is the only shore bird that lays white eggs and chicks remain inside the burrows until the fledging stage. The chicks are semi-nidifugous, unlike chicks of other shorebirds that leave the nests shortly after hatching. Parents take care of the young ones for five to six months,” he added.
