HONG KONG, Jan 6 (Reuters) - A wild bird found dead in a shopping district in Hong Kong has tested positive for H5N1 avian influenza, the government said on Saturday. The bird, a scaly-breasted Munia, was found in the Causeway Bay district on Dec. 31. Government experts said it might have been infected by migratory birds flocking south. The H5N1 virus made its first known jump to humans in Hong Kong in 1997, killing six people. So far, it cannot be passed easily from human to human, but experts fear the virus could mutate and cause a pandemic, killing millions.