South Korea on Monday confirmed the presence of avian influenza (AI) in a group of migratory birds found dead last week, suggesting a possible cause for the recent infection of poultry at farms and raising concern that the infection may spread further. Tests were conducted after some 100 migratory birds were found dead at a reservoir in North Jeolla Province in the country's southwest over the weekend, following an outbreak of AI at several duck farms. The bird flu cases have been reported at poultry farms in Gochang and Buan, all in the vicinity of the reservoir.