They apprehend that the Siberian Cranes are unlikely to ever come to the Bharatpur region of Rajasthan again as they have apparently changed their centuries-old migratory route from Siberia to India.
"These birds have not been sighted in the famous Keoladeo National Park of Bharatpur or any other place in northern India. It is clear that their route has undergone a change owing to a variety of reasons," said Dilawar Mohammed, ornithologist with the Bombay Natural History Society (BNHS).
The last time a pair of Siberian Cranes (Grus leucogeranus) was spotted in this park was way back in 2001.
"After that it has been a disappointment for bird lovers, ornithologists and tourists who used to go there for a glimpse of these royal birds," Mohammed said.
He explained that the Siberian Cranes' route to India was through Afghanistan. The adult birds stand as tall as 91 inches and can weigh over 10 kg.
Dodging the bombings by US fighter jets which tried to root out the erstwhile Taliban regime in October 2001 and after the 9/11 strikes in the US, the Siberian Cranes managed to reach India for the last time.
According to another bird lover and breeder Nigam Pandya, the Siberian Cranes or the Great White Cranes have not been sighted in this part of the world since 2001, indicating that they have skipped India completely.
"Presently, as per authoritative international estimates, there are barely 3,200 Siberian Cranes left in the world, making them among the most endangered species like the tiger or the Himalayan Pandas," Pandya told IANS.
Depending on their breeding habitats, the Siberian Cranes were classified into central, western and eastern populations.
While the central population, which used to come to India during winters for over two centuries, is now considered extinct, the western population spends its winters in Iran.
Only the eastern population with about 3,000 birds is still strong, but it is also under severe threat owing to changes in their wintering areas in China, one of them the construction of the huge Three Gorges Dam, Mohammed said.
Usually, the Siberian Cranes would start flying towards India in mid-October and stay here till March or April.
At its peak, in 1965, Bharatpur hosted over 200 Siberian Cranes. Less than 30 years later, in 1993, only five were sighted there.
Then, after a gap of three years, four were spotted in 1996. That was reduced to barely a pair of these birds by the late 1990s, following by the last pair seen in 2001.
Besides the loss of natural habitat in most parts where they lived and bred, Mohammed said, there have been reports of hunting of these huge birds in Afghanistan and Pakistan in the recent past.
The Siberian Cranes have always fascinated scientists for their ability to fly distances of over 2,500 km to escape the cold winter of Siberia.
En route, they flew over Russia, Kazakhstan, Uzbekistan, Afghanistan, Pakistan and then to northwestern India. One of their brief halting points was the Abi-I-Istada Lake in Afghanistan. From there it took them around eight weeks to reach Bharatpur.
The US-based International Crane Foundation says the eastern population breeds in northeastern Siberia and spends winters along the central Yangtze river of China.
The sparse Western population spends its winter along the southern coast of the Caspian Sea in Iran and breeds near the south of the Ob river which runs to the east of the Ural Mountains of Russia.
The central population that nested in western Siberia and flew down for warm winters to Bharatpur is no more.