Tagged Sanderling Completes Epic 7,472-Kilometer Migration to Remote Andaman Island
In a remarkable demonstration of avian endurance, a small shorebird known as a Sanderling (Calidris alba) has successfully migrated more than 7,472 kilometers (over 4,640 miles) from its non-breeding grounds in South Australia to the remote Narcondam Island in the Andaman and Nicobar Archipelago. This incredible journey, tracked via a tagged red flag coded DYM, was confirmed by the Bombay Natural History Society (BNHS) after the bird was photographed on the island by an Andaman Police officer in June 2025.
Documented Re-sighting Marks First for Narcondam Island
The Sanderling was originally tagged near Brown Bay in South Australia on April 13, 2025, by researcher Maureen Christie. Just over two months later, on June 16, 2025, it was located on Narcondam Island, representing the first documented re-sighting of a tagged bird on this volcanic island. Identified by its unique DYM tag and a yellow tag, this individual is believed to be en route to its Arctic breeding grounds after using Narcondam as a crucial stopover.
East Asia-Australasia Flyway: A Vital 'Superhighway' for Migration
This migration underscores the critically important role of the East Asia-Australasia Flyway (EAAF), often referred to as a 'superhighway' used by millions of birds during their seasonal movements. Spanning 37 countries from the Arctic Circle to Australia and New Zealand, the EAAF supports over 50 million migratory waterbirds across 210 species. Narcondam Island acts as a key refuelling stopover within this network, providing essential resources for birds like the Sanderling.
Why Narcondam Island Is a Critical Avian Stopover
Narcondam Island is a remote oceanic volcano located 140 nautical miles from Port Blair. While it is renowned for the endemic Narcondam Hornbill, recent ecological research confirms its significance as a critical stopover for many migratory birds. The island's pristine and non-fragmented littoral zones offer ideal conditions for rest and feeding, making it a vital haven for species undertaking long-distance journeys across the Bay of Bengal.
Biological Marvel: How Shorebirds Prepare for Long Flights
The journey of a Sanderling, weighing a mere 40-100 grams (about 1.5-3.5 ounces)—roughly the same as a playing card—to migrate 7,472 kilometers is a feat of biological efficiency. In preparation for migration, these birds undergo dramatic physiological changes. They enter a period of hyperphagic feeding, rapidly consuming food to nearly double their body weight through lipid storage, which provides 8-10 times more energy than proteins or carbohydrates. Additionally, some shorebirds can shrink internal organs, such as the digestive tract, to reduce dead weight and enhance pectoral muscle strength, enabling longer, nonstop flights over vast bodies of water.
Preserving Pristine Volcanic Islands for Ecosystem Health
The confirmation of the DYM-tagged Sanderling at Narcondam Island highlights the island's role in a larger, fragile ecosystem. According to the East Asian-Australasian Flyway Partnership (EAAFP), this flyway supports the highest global number of threatened migratory species. With habitat degradation from coastal development and loss in areas like the Yellow Sea and Southeast Asia, refuelling stations such as Narcondam are becoming increasingly important. As a low-human-impact volcanic island, it offers a predator-free area for migratory birds to rest without human disturbances, emphasizing the need for conservation efforts.
Narcondam as a Bridge Between Hemispheres
Narcondam Island is designated as an Important Bird and Biodiversity Area (IBA) by BirdLife International and the BNHS, primarily due to its endemic Narcondam Hornbills. This recent sighting reinforces its status as a geographic stepping stone in the Andaman Sea, facilitating migration from the Southern Hemisphere to nesting sites in Siberia. The presence of the DYM-tagged bird indicates that remote oceanic outcroppings like Narcondam are integral parts of an interconnected ecological network, rather than isolated rocks.
