Presently, we determined the pathogenicity and transmissibility of the three different clades H5 viruses in mandarin ducks to compare the potential of wild bird infection. None of mandarin ducks with H5N8 and H5N1 viruses caused severe clinical signs and mortality and the gross lesions were only observed in a few tissues of mandarin ducks; viral replication and shedding were greater in H5N8-infected ducks than in H5N1-infected ducks.