Rising temperature levels have been prompting thousands of migratory birds to return to their homeland early this winter. In an indication towards changing pattern of bird migration due to climate change, late arrival and early de-migration of migratory birds have been witnessed at prominent water bodies in the region this season. The study by Asian Waterbird Census (AWC) in the region corroborates the same.
“This winter season observed late arrival of migratory birds and short period of their stay. The migration started sometime around middle of December 2014 and with temperature levels rising from the first week of February 2015, the de-migration has already started. As a result, the region observed late migration trend whereas bird migration usually starts in October onwards and early de-migration, which usually starts in March onward,” said TK Roy, ecologist and AWC Delhi State coordinator while talking to The Pioneer.
He said, “In Punjab, major wetlands including Ramsar sites i.e. Nangal WlS, Ropar Wetland, Kanjli Wetland where water bird census 2015 was carried out by our team with the Punjab Wildlife Department in midwinter i.e. January, recorded fluctuating migratory species diversity (somewhere lesser or increased) with lesser total number in comparison to previous years. Many species of migratory birds have already left from water bodies while many others have started to return to their homeland. The same trend is followed in Haryana and Himachal Pradesh.”
Citing an example, Roy said, “A census at Punjab’s Ranjit Sagar dam recently this month recorded only 16 bird species with total number of 598 in comparison to previous year 20 species with total population of 1132. This time, major species of larger number flocks Barheadd Geese, Graylag Geese, Ruddy Shelduck, Eurasian Coot among others have left early this year.”
Besides rising temperature, there were many reasons which are resulting in early de-migration of the winged guests. This includes less rainfall in last monsoon causing completely dried up catchment area, plunging water level of the wetland and also hunting of migratory like ducks and geese at some places, informed Roy.
Every year, the visit of migratory birds depends on the climatic conditions. And, the birds’ migration is response to the changes in habitat, weather and food availability in a particular area they are living. Generally, the migratory birds reach the region by mid-November from Siberia, Central Asia, and the upper Himalayas and their stay lasts till March or April.
“Birds migration is an indicator of environment and climate change. The global climate change is now immensely impacting the migration trends of birds especially the long distant migratory birds,” added Roy.
The winter 2014 had witnessed change in the protracted trend, as even after the end of November, the migratory birds were found missing from many lakes and reservoirs in Punjab, Haryana and Himachal Pradesh. Some water bodies had witnessed arrival of migratory birds in late November, albeit, the number was very less as compared to the previous years.
The late arrival and early de-migration of the winged guests from far flung areas of Siberia and Central Asia to various parts of northern India has become a major concern for environmentalists and avian aficionados this year. Escaping cold biting conditions in their areas and braving the high snow-laden peaks of Himalayas, more than lakhs of migratory birds reach India every year.