A long-nosed fur seal has died from H5 bird flu at Beachport on South Australia's Limestone Coast, marking the first confirmed mammal fatality from the virus on the Australian mainland. The death comes days after South Australian authorities reported mass mortality events affecting more than 1,000 greater crested terns on offshore islands, and follows a little penguin testing positive on Kangaroo Island and 51 penguin deaths attributed to the virus on Tasmania's King Island. Federal agriculture minister Julie Collins called the seal's death "not unexpected," warning that significant wildlife losses cannot be avoided, while the Invasive Species Council cautioned that if the virus reaches Australia's endangered sea lion population it could constitute an "extinction level event."