Along the windswept shores of South Australia's Limestone Coast, seven greater crested terns have fallen ill or died in what may signal a new chapter in Australia's encounter with H5 bird flu — not a virus arriving on the wings of distant migrants, but one that may now be passing between birds on home soil. With twenty confirmed cases spread across four states and urgent laboratory work underway at CSIRO, the nation watches a familiar tension unfold: the slow, careful work of science racing against the unpredictable movements of nature. Human health risk remains low, and poultry systems appear