Santragachhi Jheel in Howrah, Purbashtali in East Burdwan, Rani Pukur near Haldia, Jhaugheria and Kanaichatta in East Midnapore, Amlamethi Char in the Sunderbans and Bilkurul Jheel in Murshidabad have all recorded far fewer bird arrivals by the November-end than in the past.
“In two-and-a-half decades of tracking birds, I have never seen so few numbers arrive at the lakes and jheels in south Bengal. Though the peak season for arrival of migratory birds in this region is between mid-December and mid-February with the maximum bird count being recorded around mid-January, usually a fair number of birds start arriving from early November when the temperature begins to dip. But this year, it is still fairly warm and it has rained till very late,” recounted Arjan Basu Roy of Nature Mates that helps nurture bird habitats.
Raja Chatterjee of wildlife conservation organisation Junglee, who has been associated with bird habitat conservation for nearly three-and-ahalf decades, says he cannot remember so many extreme events in a year.
“South Bengal has experienced four cyclones and over six depressions. If the rainy season gets prolonged, the winter gets delayed. Hence, their delayed arrival. The migration of local birds like lesser whistling duck has been badly affected,” said Chatterjee, who in 1988 discovered Purbasthali was a hotspot for migratory birds.
One of the major effects of climate change is the loss of habitats that migratory birds depend on along the migration route.
Global warming also influences the routes of many migratory birds and their annual migration rhythm. A lot of migratory birds change their routes, shorten or completely cancel their journey as a result of changing temperatures.
Also, mild winters help resident birds to survive and they start to use food resources and breeding places of long distance migrants. This increases the competition between the species for food and breeding grounds.
Birders like Suvrajyoti Chatterjee are hoping the climate change is not drastic enough to alter the route of trans-Himalayan birds that arrive from mid-December and bring joy to several hundred passionate bird lovers who eagerly wait for the winter.
“We are keeping our fingers crossed,” he said.