Along the coastlines and enclosures of New South Wales, a quiet but consequential experiment has begun — one that asks whether human ingenuity can outpace a virus threatening some of Australia's most irreplaceable birds. Taronga Zoo this week initiated H5N1 vaccinations across 70 animals from 18 species, as state authorities confirmed 16 infections and began planning an expansion to wild populations. The effort reflects a broader reckoning with avian influenza's reach, and the fragile line between a species' survival and its disappearance.