Kendrapara: With the onset of winter, the chirps of overseas winged guests have livened up the picturesque marshy wetlands in the Bhitarkanika national park here.

Birds of central Asian origin have begun arriving at the wetland spots of the national park which was recently inspected by a team of the International Union of Conservation of Nature (IUCN) for its likely conferment of UNESCO's World Heritage status.

"Over 75,000 birds have already arrived. Their number would swell considerably by December end as they keep coming daily. As the wetlands in Bhitarkanika are free from human-interference, birds fly their way from cool northern hemispheres to the park in large numbers," said Divisional Forest Officer, Rajnagar Mangrove (wildlife) Forest Division, Bimal Prasanna Acharya.

The migratory birds will roost here till March end. A majority of them will fly back then to the original habitat.

Some species may stay back if cold conditions prevail.

Since the past one week, flocks of these winter guests have been crowding the Raipatia and Satabhaya water bodies and creeks.

The habitat of these birds extends around a km stretch. There is ample food for the birds as the place is crisscrossed by innumerable water inlets and nullahs, Acharya said.

Prominent among the visitors this time are Indian Skimmers, Grey Pelicans and White-backed vultures, Lesser adjutant, Grater spotted eagles. All of these sighted species are given endangered status under IUCN s Red Book Data containing the list of highly threatened animals worldwide, he said.

These apart, other delicate and prominent birds sighted this time are Black-tailed godwit, Northern pin-tail, Lesser whistling duck, Grey plover, Egret spotted bills, Oriental darter, White belley seagull and black-necked stork.

These species barring the white-backed vultures are winter migrant avian creatures from northern hemisphere and cool places like Ladakh and they used to prefer the Bhitarkanika wetland for its unique eco-system and cool and serene environment, conducive for their winter habitation, he said.

Unbearable cold during winter months forces these migrant species to temporarily leave their original habitat.

Chilka and Bhitarkanika wetlands in Odisha are favoured destination of these migratory birds, he said.