Now is probably not a good time to watch Alfred Hitchcock’s The Birds. The U.N. is warning that the bird-flu virus may return, on reports that a mutant strain has emerged in Asia. This mutant H5N1 avian virus is not vulnerable to currently used vaccines. So far, eight people have died this year, and 331 since 2003. The mutation has been seen in Vietnam and China, but may also threaten Thailand, Malaysia, Japan, South Korea, and Cambodia. Scientists believe the virus could spread across the world by wild-bird migration.