New Zealand’s fight to protect its most vulnerable bird species has entered a critical stage as scientists prepare for the potential arrival of highly pathogenic avian influenza (H5N1), a virus that has devastated bird populations worldwide.
Among the species at greatest risk is the kākāpō, a critically endangered, nocturnal, flightless parrot sometimes dubbed the world’s fattest bird. With fewer than 250 individuals left, the species could be pushed to extinction if the virus reaches New Zealand’s shores.
So far, Oceania has remained free from H5N1, but conservationists fear this could change as spring migration season brings thousands of seabirds from infected regions. A single carrier could be enough to unleash a crisis.
In response, New Zealand’s Department of Conservation (DOC) has completed a world-first vaccination trial on five of its rarest bird species, all with populations under 500. Using a licensed H5N3 poultry vaccine, scientists inoculated captive individuals of the kākāpō, takahē, kakī (black stilt), tūturuatu (shore plover), and a kākāriki species. Four of the five developed strong antibody responses lasting at least six months.
“This is about protecting core breeding populations that are vital to keeping these species alive,” said Kate McInnes, DOC wildlife veterinarian and senior science adviser. Captive breeding programmes are seen as lifelines for species already on the brink.
New Zealand now faces the challenge of designing a deployment strategy before migratory birds return. Vaccinating free-living wild populations remains logistically near-impossible, but managed populations on offshore islands or in aviaries could be protected.
Other countries are watching closely. Australia has invested A$100m (£48m) to prepare for bird flu, including A$2.8m for safeguarding threatened species, while running parallel vaccine trials on stand-in bird species. “It’s not a matter of if, but when bird flu arrives in Australia,” said Fiona Fraser, Australia’s threatened species commissioner.
Globally, vaccination of wildlife has been rare but not unprecedented. California condors in the US were given emergency jabs after 21 birds died of H5N1 in 2023, and other conservation programmes have experimented with vaccines for koalas, Ethiopian wolves, and Hawaiian birds.
However, experts caution that vaccination is no silver bullet. Outdated vaccines may struggle against evolving virus strains, and incomplete coverage could even encourage stronger viral variants. There are also ethical and logistical challenges in capturing endangered birds for repeated doses.
For now, New Zealand conservationists are racing against time, weighing when to launch vaccinations for maximum impact. “If we start too soon, we’ll lose that antibody protection. If we start too late, we may miss the crucial moment,” McInnes said.
The stakes are enormous: for the kākāpō and other critically endangered species, the arrival of bird flu could mean the difference between survival and extinction.
