More than 21,000 waterbirds of 69 species were spotted in Tamil Nadu's Tamirabharani river irrigation tanks. The count covered 68 tanks in Tirunelveli, Tenkasi, and Thoothukudi districts. Over 250 volunteers helped survey these wetlands from January 23 to 25, 2026. The Tamirabharani river system is vital for the region's agriculture and wildlife. The irrigation tanks serve as key homes for about 100 bird species, including over 30 migratory types. Kadambakulam tank in Thoothukudi district saw the highest count with 2,292 birds. Species like Little Cormorant (2,579 individuals) and migratory Whiskered Tern (1,148) were among the most common. "More than 36% of the recorded birds were migratory species, using the Central Asian Flyway," said M. Mathivanan, coordinator of the Tamirabharani Waterbird Count. Important breeding sites were found in tanks across Tirunelveli and Tenkasi districts. Thoothukudi accounted for over half the birds and 80% of species diversity, showing the importance of its large tanks. However, threats like waste dumping, invasive species, and sewage pose risks to these habitats. "The protection and sustainable management of these irrigation tanks are essential for waterbird conservation," added Mathivanan. The annual count is run by several local organizations to promote conservation of these valuable wetlands.