Everything we know about stoats shows that they are remarkably resistant to eradication. Any new tool effective enough to exterminate them at national scale would be expensive and difficult to develop. Official attempts to fund the research needed started in 1999 with a grant to the Department of Conservation of NZ$6.6 million. It produced a new humane trap but no advances in fertility control. PFNZ2050 was launched in 2016, a hugely expensive programme with a much larger budget and a stated vision of restoring the dawn chorus that galvanised hundreds of community groups. They are now achieving impressive results at the local and temporary level, by routine and widespread deployment of conventional technology. Their work is essential to protect what biodiversity we have left until we can think of better ways to save it. Killing stoats is not as difficult now as preventing them from reinvading. Offshore islands are safe if >5 km from shore; the best mainland equivalents are fenced sanctuaries. By 2019 there were 14 of these, half ring fences, half on peninsulas. National implementation of these would cost about the same as PFNZ2050 and provide the best permanent protection for deeply endemic species available to date. Fence damage and unexpected incursions are possible but uncommon, and monitored 24/7.