Bhubaneswar, Jan 12 (IANS) More than 4.5 lakh migratory birds belonging to 101 species from as far as Siberia, Iran, Iraq, Afghanistan and the Himalayas have arrived at the Chilika Lake in Orissa for their winter, an official said Wednesday.

Around 269,000 migratory birds were sighted in the 15.53 sq km-Nalabana bird sanctuary - an island in the lake. The remaining birds were spotted outside the sanctuary area.

"It was a rough estimate," B.P. Acharya, divisional forest officer of the Chilika wildlife division told IANS, adding that the exact number of birds visiting the lake would be known after the annual bird census was completed.

"The latest figure was generated on the basis of the feedback we received from the field staffs at 21 camps set up to protect birds around the lake," he said.

He said the two-day bird census at the lake, spread across the districts of Puri, Khurdha and Ganjam along the east coast, would be carried out Jan 18-19.

Chilika, about 100 km from state capital Bhubaneswar, is the largest brackish water lake in Asia covering an area of over 1,100 sq km.

It is considered one of the hotspots of biodiversity in the country and a great attraction for the tourists for fishing, bird watching and boating.

The lake is considered as the largest wintering ground for migratory waterfowl found anywhere on the Indian sub-continent. About 10 lakh migratory birds visit the lake in October and return in March.

About 9.24 lakh domestic and migratory birds were sighted at the lake during the census conducted Jan 10-11 last year. The birds which were spotted in the lake included flamingos, grey and purple herons, egrets, spoonbills and storks.