In a first-of-its-kind happenstance, two bar-headed geese tagged with solar-powered GSM-GPS transmitters in Bihar's Nagi Dam Bird Sanctuary have winged their way to the wetlands of Tibet after around a month-long journey, it was learnt.
The Bombay Natural History Society (BNHS) fixed solar-powered GPS-GSM tags (transmitters) on these two geese — Gagan and Vayu — at Nagi Dam Bird Sanctuary in Jamui district on February 22, 2025.
It was the first time the GPS-GSM technology was used to track the bar-headed geese, known to attain the highest altitude in flight for migratory bird, to track their precise movement. “The two geese will provide critical data on migration routes, stopover sites, and their behavioural patterns. It will help us in further strengthening wetland conservation strategies. It is the first ever instance of tag use on migratory birds in Bihar,” said Sunil Kumar, Bihar Environment, Forest and Climate Change (BEFCC) Minister.
As per the latest update, both geese are moving separately but are present in the Tibet wetlands. While Gagan is in the northwest side of the wetland complex — Nagarze county and Yamzho Yumco, Vayu is in South Tibet. Officials involved in the project said the data will also help in understanding the geese's journey from non-breeding areas to breeding grounds in the Central Asian Flyway.
“As these bar-headed geese follow the Central Asian Flyway (CAF), it was decided to track the movement of this specific goose species. Also, the local movement of this species, in and around the Nagi Dam, will be known. This information will play a vital role in strengthening wetland strategies,” the Minister said. The Nagi Bird Sanctuary is a 200-hectare wetland, a prime location for migrating birds in the winter season from October to April. It was declared a bird sanctuary in 1984. It has also been designated an Important Bird Area (IBA) by Birdlife International. Migratory birds like Bar-headed Goose, Greylag Goose, Northern Pintail, Red-crested Pochard, Steppe Eagle, Taiga Flycatcher etc flock to the sanctuary after travelling from the faraway Himalayas, Europe, north Asia and even the Arctic Circle.
Apart from migratory birds, a wide variety of resident bird species like the Ashy-crowned Sparrow Lark, also inhabit the sanctuary and its surroundings throughout the year.
Explaining the route followed by Gagan and Vayu, Principal Chief Conservator of Forest, Prabhat Kumar Gupta, said that bar-headed geese have a breeding range that stretches from Mongolia, through Russia and western China to Tibet and as far west as Kyrgyzstan. They migrate over the Himalayas to spend winters in parts of South Asia (from Assam to as far south as Tamil Nadu). It is one of the species that exclusively migrates along the CAF, Gupta added.
The officer said both Gagan and Vayu left the Nagi Dam and reached Nakti the very next day and were moving between the areas near Bhimbandh and a little westward to the place Naukadih.
“On March 6 at 10.54 am, we monitored Vayu soaring up to an altitude of 4,898 metres as it traversed the Indian border, travelled between Bhutan and Sikkim. The bird entered the Tibetan Plateau, flying at a speed of 59 to 74 km per hour. On March 9, it took a circular route, probably exploring a habitat suitable for its sojourn.
“Between February 22 and March 6, Gagan remained active at Nagi Dam, where it was tagged at 24.81°N, 86.40°E position. On March 7 at 08.28 hours, it left Nagi Dam and reached the sandbars in the Ganges near Bhagalpur, 80 km in aerial distance,” Gupta said.
After spending 36 hours there, in two locations in Ganga river, it took wings to reach Nepal. Unlike Vayu, Gagan took a lower-altitude migration route, maintaining a steady northward movement without climbing extreme heights to reach the Terai region of Nepal. Gagan's highest recorded altitude is 640 metres so far, Also, it has been flying at the speed of 56-57 km, said Gupta.
