Leg tag decodes journey: Critically endangered bird on Bengal beach flew 8,000km from Russia

Kolkata: A spoon-billed sandpiper that was sighted recently on the Patibunia beach near Bakkhali may have travelled close to 8,000km from the Chukotka region in Russia, where it was tagged on July 6 last year, according to researchers working on the conservation of the critically endangered species.A lime green tag on the bird's right leg and a unique code written on it helped researchers decode its journey. Less than 500 spoon-billed sandpipers now survive in the wild, experts said.Birder Sandip Das, a founder member of the Kolkata-based Birdwatchers' Society, clicked a spoon-billed sandpiper on the Patibunia beach on March 29, but that bird did not have a tag. Das was accompanied by fellow birders Soumya Aon and Kaustav Khan during the sighting."Two days later, Jayanta Manna was the first to click another spoon-billed sandpiper on the beach. This one had a lime green tag on its right leg," said Das. The sighting spurred a series of hectic communications among experts and researchers, including Bangladesh-based scientist Sayam U Chowdhury, who has worked on the conservation of the species in Russia's Chukotka. Scientists at Zoological Survey of India, too, were approached.Das said the words ‘Lime 2K' written on the tag helped experts ascertain that the bird was "banded as a wild chick at Meinypilgyno, Chukotka, Russia on July 6, 2025". This is reportedly the first sighting of the bird since it began its epic journey along the East Asia-Australasian flyway after being tagged. Spoon-billed sandpipers are attached lime green tags and marked as adults or chicks in their wild breeding grounds in Chukotka, in north-eastern Russia. "These tags are part of a crucial conservation effort to track the critically endangered birds," Das said.The tags often have letters or numbers so conservationists could track individual birds along their migration route through Asia, including stopover sites such as Rudong in China. Each tag colour represents a specific population or rearing method. While lime green is reserved for wild-born birds, white indicates head-started chicks (captive-bred) and yellow refers to birds tagged at stop-over sites. The markings are given as part of the conservation efforts by Spoon-Billed Sandpiper Task Force.Sightings of these birds, often reported by volunteer birdwatchers, are valuable as they provide critical data on survival rates and migratory patterns.The first documented sighting of a spoon-billed sandpiper in Bengal was reported on April 1, 2018. Across India, there have been very few sightings. One such was reported by S Balachandran, a scientist at Bombay Natural History Society, from Tamil Nadu in 1996.