The park, listed by UNESCO as a World Heritage site, is home to 375 species of birds of which, says Prasad, about 100 species migrate annually from Europe, Siberia, China and Tibet.
"We get around 20,000 waterfowls coming here for the winter," Prasad said, adding that though the main migratory period is in December, already some 5,000 birds — mainly Chinese coots and pintail ducks — have already arrived.
Those expected in the next weeks include common cranes from Siberia; ducks such as teal, ruddy shelduck, mallard, shoveler, red-crested pochard and gadwall; and bar-headed and graylag geese.
As at wetlands across India, a strict watch is being kept by staff for signs of illness among birds in the park, which is very popular with tourists.
"There has been no sign of anything so far," said Prasad, adding that veterinary officials would soon start taking blood samples from migratory birds.
Pritam Singh, who has spent every winter for the past 12 years guiding tourists around Keoladeo in his cycle rickshaw, is convinced all the birds that have arrived so far for the winter are healthy.
"I know their calls. They arrive at three or four in the morning. They have been making their familiar 'quack, quack' sounds. Nothing is wrong," Singh told AFP.
Precautions, meanwhile, are being taken, according to wildlife and veterinary officials amid concerns that migratory birds could spread the deadly H5N1 strain of avian flu, which has already jumped from Asia to Europe.
The fear is that the more the virus spreads the greater chance it has to mutate, picking up genes from ordinary flu that could make it highly contagious from human to human.
