Winter is yet to set in Orissa but the winged guests have started thronging Chilika, the biggest waterfowl habitat in the country. Wildlife officials have spotted a number of migratory birds in Nalabana Island, the bird sanctuary inside the 1,100 sq km lake, during their field visit over the weekend as part of a training programme on bird identification. DFO (wildlife division) B P Acharya said, migratory birds including northern pintail, gadwall, yellow wagtail and pratincole were spotted in the 15.59 sq km Nalabana area. He, however, said migratory birds were yet to be spotted in large numbers in other parts of the lake.