Bird flu follows avian flyways

Deadly H5N1 influenza travels with migrating wildfowl

Ruddy shelducks

ON THE WING  Ruddy shelducks (Tadorna ferruginea) and other wild birds may spread the deadly H5N1 virus along their migration routes in Asia.

Courtesy of Chao Zhao

Wild geese may fly with the flu on their wings, new research suggests.