Subantarctic bird flu devastates seal pups on Heard Island, scientists say

A deadly H5N1 bird flu outbreak has hit Heard Island and McDonald Islands, killing an estimated 13,000 seal pups and hundreds of adult king penguins. Drone surveys showed about 76% pup mortality across 17,000 pups, with one area at 97%. Genetic data suggest the virus arrived from the Crozet Islands around August 2025, marking the virus’s eastward spread to Australian external territory; the impact on breeding adults is still unclear and the study (BioRxiv) has not been peer reviewed. As of February, the Australian mainland and New Zealand had no reported H5N1 cases.