The deadly H5N1 bird flu has been confirmed in New Zealand for the first time, sparking alarm that some of the country’s most beloved and vulnerable native birds could be wiped out if it spreads.

A single ocean-going seabird, a brown skua, returned a confirmed positive test on Wednesday, after it was found on Petone beach in Wellington on 10 July, said Andrew Hoggard, the biosecurity minister.

In New Zealand, where birds hold a significant place in the culture and ecosystem, the virus has the potential to be catastrophic. However, New Zealand has been preparing for the possible arrival of bird flu for years and a vaccination programme is under way for five species of endangered birds in captive breeding programmes, including the charismatic kākāpō and takahē. The ministry for primary industries said it has a well-established surveillance programme that spans wildlife sanctuaries, zoos, the poultry industry, vets and the public.

“Bird flu is an unwelcome threat to our bird species who are already under more extreme and multiple pressures than ever before,” said James Russell, professor of conservation biology at the University of Auckland.

“Ultimately, there will be little we can do to stop this virus impacting our wild bird populations, but through taking meaningful actions which reduce other pressures, we can set up our bird populations as strongly as possible to recover after the virus has swept through.”

Hoggard said: “There is no evidence of any mass mortality in wildlife or transmission between wild birds in New Zealand.” However he urged the public to be vigilant.

“We are continuing to act early and prepare carefully, while asking the community to remain watchful and report three or more sick or dead birds in a group to the pest and disease hotline.”

The deadly bird flu strain started in Asia, and has been spreading across Europe and the Americas since 2021, arriving in Antarctica during the 2023-24 summer. Australia recorded its first confirmed cases on the mainland in early July.

The virus has killed millions of birds worldwide and in some areas, reduced bird populations by 75%. Signs of disease include weakness and seizures, head twisting, and breathing distress.

New Zealand’s only endemic mammal species are bats and marine mammals. Consequently, its birds evolved in unusual and idiosyncratic ways. The country is home to more species of flightless birds, both living and extinct, than any other place in the world and has the most diverse population of seabirds globally.

About 80% of native birds are already considered endangered, with more than a dozen on the verge of extinction.

Jemma Geoghegan, a virologist at the University of Otago, said New Zealand had an advantage because it was “not facing this blindly”.

“We can draw on several years of international experience, including the recent Australian response, to guide surveillance, wildlife monitoring and outbreak management.”

However, the virus presented a “big unknown” because not all species are equally susceptible, said Nigel French, distinguished professor of infectious disease epidemiology and public health at Massey University.

Species that tend to gather in large colonies, particularly shorebirds and other scavenging species, are likely most at risk, French said. Many of these are types of birds that are already endangered, including the fairy tern – population 50.

Marine mammals, such as New Zealand’s nationally endangered sea lions, were also at risk of catching the virus.

“It could be really devastating for some of our taonga [treasured] species of birds and some of the rarer native species.”

Because New Zealand’s bird populations have such huge cultural significance and are particularly vulnerable, it was important the country pulled out all the stops with vaccination and containment, French said.

“It is a deep cultural concern for New Zealand as a whole.”