The adverse effect of global climate change on the migratory birds coming to Uttarakhand is being marked by the ornithologists and the scientists based the State. They are concerned over the number of these winged guests dwindling fast over the past decade.
Even a decade back, around 70,000 such birds belonging to at least 76 species used to visit the areas swept by the Ganga in the state. But the number has been reduced to nearly 50,000 over the past 10 years. The count of Siberian cranes which are found across the world has become limited to just 3000 and similar observations have been highlighted in a recent study conducted by the scientists of Gurukul Kangri University of Haridwar and H N B Garhwal University of Srinagar Garhwal.
According to the study, a marked change has been observed in the migration pattern of the winged guests which come from far- off lands in the winters and return during ‘Basant’ season over the past one decade.
The climate change has also resulted in the change in the breeding pattern of these birds too.
Take the instance of Pied Fly Catcher which has started coming earlier to Uttarakhand for breeding than their earlier timing of arrival. The same is the case with the winter migratory bird Rajhans (bar headed goose) which has started delaying its flight from the lake Mansarovar. In 2015-16, it was spotted at the end of December whereas this year the flock of this rare Rajhans was seen in the second week of January. It stayed for a short period in the Ganga river plains and returned in the first week of March.
Speaking to The Pioneer, the renowned bird scientist Dinesh Bhatt of Gurukul Kangri University of Haridwar said, “This time eight pairs of Rajhans were seen coming from Mansarovar to Misserpur wetlands of Haridwar and not a single bird was marked in the Bhimgoda barrage and Aasan Barrage of Dehradun.”
It is mention worthy here that the bar- headed goose is the lone such bird which crosses the high altitude Mansarovar lake of Himalayan ranges in nearly 15 days and reaches the plains of Haridwar. This migratory bird takes a flight of 70 to 80 kms per day.
The rich biodiversity of Uttarakhand, the Ganga river wetlands, cool climate in winters and ample sunshine is what attracts these winged guests come to Ganga and Yamuna river valleys. To escape the chilly winters in their native lands, these birds come to Ramnagar wetlands of Nainital, Aasan Barrage of Dehradun, Dakpathar Barrage, Pashulok Barrage of Rishikesh, Bhimgoda Barrage and Misserpur wetlands. They return with the onset of summer in March.
Ramganga water reservoir of Uttarakhand receives the maximum number of migratory birds while Pashulok barrage in Rishikesh get the minimum visitors. These areas receive birds from lands of Northern Siberia, China, Mangolia, Kazakistan and Ukraine. The longest flight is taken by the Eurasian Karlu and Marsh Sand Piper from northern parts of Russia to Uttarakhand while Surkhab species of birds cover 500 km flight from China and Tibet to come to Uttarakhand.
The head of department of Zoology and environmental science Gurukul Kangri University Dinesh Bhatt told The Pioneer that these migratory birds come to Uttarakhand after spending some time in the states of Punjab and Himachal Pradesh. Bar- headed goose comes directly to the plains of Haridwar after crossing Himalayas.
The global warming has affected the Eurasian Karlu the most and has resulted in reduction of their numbers. The species has come to be listed in endangered category.
The head of department of HNB Garhwal University Professor Ramesh Chandra Sharma says that the rising temperatures in the northern parts of the earth have resulted in change in the cycle of the migratory birds and their numbers have reduced. “The delay in onset of winters in Uttarakhand and early summers is affecting the breeding pattern and stay period of these migratory birds. Ten years ago, the winter period started in Ganga Yamuna river regions in the end of October and lasted till April month. These birds thus used to stay longer for the need of their food. But the development in the state leading to deforestation and mining in Ganga has disturbed the entire biodiversity of the region. The food is becoming scarce for them which is why they are returning early.”