Fewer birds have visited Odisha’s Chilika Lake, Asia’s largest brackish water lagoon, this winter compared to previous years, according to the annual bird census conducted on January 18, 2025. However, the census also recorded a rise in the number of bird species visiting the 1,165-square-kilometre lake.
This year’s mid-winter bird survey recorded 1,127,228 birds of 196 species, including migratory and resident birds, said Amlan Nayak, divisional forest officer (DFO) of the Chilika wildlife division. The count included 1,087,226 migratory birds of 109 species and 40,002 resident birds of 87 species.
In comparison, last winter’s census recorded 1,137,759 birds of 187 species, comprising 1,098,813 migratory birds of 108 species and 38,946 resident birds of 79 species. In 2023, 1,131,929 birds of 184 species were recorded, including 1,093,049 migratory birds of 105 species and 38,880 resident birds.
Meanwhile, bird populations in Odisha’s Hirakud wetland, a Ramsar site, and Bhitarkanika National Park have increased this year. The bird counts were held at these sites at the same time.
This year, the Hirakud reservoir, which covers approximately 700 square kilometres, hosted 3,77,732 birds of 122 different species, up from 3,42,345 birds of 113 species in 2024. In Bhitarkanika, 1,51,614 birds of 118 species have been sighted this year, compared to 1,51,421 birds of 121 species the previous winter, according to forest officials.
On the other hand, the 15.59-sq km Nalabana Wildlife Sanctuary within the Chilika Lake hosted the highest congregation of birds, with 3,43,226 counted this year, slightly fewer than the 3,47,280 recorded last year.
Experts attributed the marginal decline of 10,531 birds to increased water levels in the lake caused by untimely rains in December 2024. “The high water level reduced the availability of mudflats, which are crucial for waterfowls,” explained Nayak. This may have prompted many migratory birds to settle in nearby farmlands and wetlands where food was more abundant, he added.
SS Srivastav, former principal chief conservator of forest (wildlife wing), called the decline a “natural phenomenon.” He noted that the migratory birds destined for Chilika might have temporarily moved to adjacent wetlands due to the changed water conditions.
Gadwalls were the most numerous species sighted, with a count of 2,01,926, followed by Northern Pintails (1,93,394) and Eurasian Wigeons (1,54,937), the census revealed. Greater flamingos also saw a significant rise in numbers, with 2,638 recorded this winter compared to 820 last year.
The bird census was a joint effort by the Chilika wildlife division and the Chilika Development Authority (CDA), with technical support from Sujit Narwade, deputy director of the Bombay Natural History Society (BNHS).
A total of 126 experts, including researchers, wildlife activists, bird enthusiasts and representatives from organisations such as BNHS, the Wildlife Institute of India and Odisha University of Agriculture and Technology, participated in the census .
Chilika Lake is a vital wintering ground for migratory birds from beyond the Himalayas, including regions such as Northern Eurasia, the Caspian, Siberia, Kazakhstan, Lake Baikal and remote parts of Russia and neighbouring countries. These winged guests arrive in Chilika to escape the harsh winters of their native habitats and begin their homeward journeys before the onset of summer.