A greater crested tern found on Sydney's Northern Beaches has tested positive for H5 bird flu, drawing Australia's largest city into an outbreak that has now touched nearly every major population centre since the virus arrived on the continent in June. With 468 documented events across Adelaide, Melbourne, Brisbane, Perth, Hobart, and now Sydney, Australia has become the last continent to confront this particular strain — a distinction that carries both scientific weight and ecological urgency. Authorities are candid that wild bird populations cannot be shielded by policy alone, and so the wor