Sambalpur: The Hirakud Wildlife Division officials have started the annual bird census at the Hirakud Dam site spread over 500 square kilometers. The census began at 5 am in the morning and will continue till 5 pm in the evening. The entire area has been divided into 21 sectors that will be surveyed by 32 teams. Officials from Sambalpur, Bargarh and Jharsuguda districts will join the census operations. About 30 Forest Department officials and 78 experts will also be part of the teams. According to sources, last year the dam area had attracted more than 3.16 akh migratory birds and the number is likely to rise this year.