Migratory birds at Kanke dam in Ranchi on Friday. Picture by Manik Bose

Ranchi, Dec. 5: The Himalayan visitors, who flock the cool waters of Getalsud, Kanke and Rukka dams every winter, seem to have dropped Jharkhand from their itinerary this time.

Though reasons there may be many, the primary cause behind this change in flight plan of migratory birds is believed to be the sharp two-degree rise in normal temperature.

Experts say this year only 1,500 birds were seen in and around the capital. This is barely 4 per cent of the number of winged guests who had made the state their winter haven last year.

“There were more than 50,000 birds from the Himalayan region last season. They were seen frolicking in the waters of Getalsud, Kanke and Rukka reservoirs. This time it is a sorry figure. Climatic conditions are to be blamed for this sudden change in migratory behaviour,” said professor A.K. Singh, the dean of veterinary science at Birsa Agriculture University (BAU), Kanke.

Chief wildlife warden S.K. Sharma said migratory birds that usually find their favourite perch on the dams are painted stork (though not a Himalayan resident), snake bird, cormorant, common teal, grey teal, shovellers and pochard. This year, however, only a few painted storks, snake birds and cormorants have made the state their winter home.

Weather scientists point out that the region is undergoing a climatic change. There has been a two degree rise in the normal temperature this year. Normally, during the winter, the temperature in the state hovers around 10°C. This time, it is kissing 12°C.

The birds migrate to temperate zones such as Jharkhand and neighbouring Bengal to escape from the Himalayan chill.

But the rise in temperature has made their winter habitat too warm for a long stay.

“The birds usually stay in this region till the end of winter. If on the one hand they cannot stand the biting cold in the Himalayas, on the other, they cannot bear the summer heat. The sharp rise in temperature is the primary reason behind this change in migratory behaviour,” said an expert.

A. Wadood, a weather scientist at BAU, blamed global warming and pollution for the increase in temperature. “Air pollution is one of the major reasons behind global warming. A time may come when the rising level of pollution will force the winged visitors to stay away from Jharkhand forever,” he said.

Experts also fear that scarcity of food and water pollution will compel the birds to change their route of migration in the near future.