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In a first-of-its kind study in eastern India, a bar-headed goose fitted with a GSM-GPS transmitter has revealed its migration route and flying pattern.
The bird, named ‘Gagan’, successfully crossed the Himalayan range and visited a large lake in Tibet, its tracking record highlighted. It covered roughly 780 kilometres (migration cycle of 1,560 km) and was recorded at heights of 5,220 metres.
Anand Kishor, principal secretary, Environment, Forest and Climate Change Department, Government of Bihar, said the tracking record of a tagged bar-headed goose will help researchers and conservationists to understand the flight paths and behaviours of migratory birds.
The bar-headed goose is the highest-flying migratory bird in the world.
Arvind Mishra, a Bihar-based bird expert, said such hi-tech tracking of a bar-headed goose, had never been conducted before in the state. “It will strengthen the conservation of mainly migratory birds in the state.”
Gagan, along with another bar-headed goose named ‘Vayu’, was tagged with a solar-powered GSM-GPS transmitter and released in February this year at the Nagi Dam Bird Sanctuary in the state’s Jamui district.
The tagging operation was conducted under the supervision of Sathyaselvam, a scientist at the Bombay Natural History Society. The non-profit, along with the Environment, Forest and Climate Change Department, supervised the study. Sathyaselvam affixed the transmitter to Gagan and Vayu, monitored satellite data and analysed it to chart their migration journey.
Gagan returned to the sanctuary in the first week of December 2025, having completed its migration journey of over nine months. “It was spotted on December 6 at the sanctuary by field officials and researchers.”
Last year, the Nagi and Nakti Bird Sanctuaries were recognised as ‘wetlands of international importance’ under the Ramsar Convention.
In 1984, the human-made wetlands were designated as bird sanctuaries, highlighting their importance as wintering habitats for several migratory species. Over 20,000 birds congregate at the sites during the winter months. This includes one of the largest congregations of red-crested pochard (Netta rufina) on the Indo-Gangetic Plain.
According to the Asiatic Waterbird Census (AWC) 2023, the Nakti Bird Sanctuary is the wetland with the highest number of birds reported, with a count of 7,844 birds. It is followed by the Nagi Bird Sanctuary with 6,938 birds.
Thousands of migratory birds visit different wetlands of Bihar during the winter season.