Mumbai, Jun 2 (IANS): A Curlew Sandpiper tagged in Mumbai by Bombay Natural History Society (BNHS) has been spotted in the Tianjin province of China, around 4,500 km away, marking a significant achievement in studying bird migration, officials said here on Wednesday.

The bird - which breeds in the Tundra of Arctic Siberia is strongly migratory, wintering in Africa and also south and south-east Asia besides Australia and New Zealand - was tagged by the Bombay Natural History Society (BNHS) scientist Mrugank Prabhu and his team.

It was first caught and tagged in a wetland near the Palm Beach Road at Nerul in Navi Mumbai on March 18, 2019 with a unique Flag No. 7N5, and later it was captured against on January 13, 2020, at the Bhandup Pumping Station in Mumbai.

The same Curlew Sandpiper has now been resighted at Tianjin in China on May 6, 2021, during its northward migration to its breeding sites, said Prabhu.

"The migratory birds wintering at Thane creek use the adjacent wetlands as their high-tide roosts. They show high fidelity to their traditional feeding and roosting sites as evident from their frequent resightings at these wetlands in the same as well as subsequent migratory seasons. This signifies the importance of these habitats and the urgent need for their conservation," BNHS Director Bivash Pandav said.

The bird tagged by Prabhu and his team was resighted in the Tangu Saltpans in Tianjin, China, near the shoreline. Tianjin province of China is the first record of international resighting of a waterbird tagged on the coasts of Mumbai and adjoining wetlands, he added.

Currently, President of the Convention on Migratory Species, since 1927 the BNHS is an old hand at bird banding and ringing which reveal fascinating insights into the migrations of the birds, the political boundaries they cross and the potential hurdles they conquer en route, said Pandav.

The birds are tagged either with a band of a light-weight metal ring having a unique alpha-numeric code, colour flags, colour bands or neck-collars on certain species in accordance with international protocols.

India falls under the Central Asian Flyway (CAF - the paths birds follow in the sky) mainly for the North to South winter migration.

The country has recently launched a National Action Plan for the flyway and a network of 29 sites comprising 20 major wetlands and nine wetland clusters are identified as critical sites for the migratory waterbirds under the CAF-NAP which are being surveyed by the BNHS.

Annually, around 50-billion birds migrate across the world on their preferred routes with the timing of travel and the ecology of migration shrouded in intrigue and the bird ringing, recapture, the resighting method is used to study this process and help scientists discern the migratory 'flyways' of these avians.

In past nearly four years, in Mumbai along around 10,000 birds of 36 species have been ringed or color-flagged and in the past other studies, various species of gulls, terns, shorebirds, flamingos ringed in Central Asia, the Persian Gulf, eastern Asia and Indian Ocean islands have been recorded on the Maharashtra coast, said Pandav.