Black-billed gull

You may have read reports from around the world about a new and very concerning strain of the avian flu virus since 2020, starting in Europe, spreading across the USA, then to South America and then Antarctica, Africa and Asia.  Working with seabirds as we do and while acknowledging that the risk of it arriving in New Zealand is low, it is important for the Trust to be prepared and to play our part in minimising any risk of spreading avian influenza, should it arrive here.

One thing we can do is share information with you.


First a bit of background.

Avian influenza was first described way back in 1878 when a contagious disease of poultry was described in northern Italy.  In 1955, it was found to be a type A influenza virus and from 1981, it has been known as highly pathogenic avian influenza or HPAI.  Highly pathogenic avian influenza viruses cause severe disease and can cause high mortality in infected birds, especially in poultry.  Ducks can be infected without signs of illness.  Some HPAI virus infections in poultry can spill back into wild birds, resulting in significant geographic spread of the virus as those birds migrate.  Again, some wild birds can be infected without appearing sick but others through some virus subtypes can suffer severe disease and mortality.  The US Centers for Disease Control has this information about bird flu if you would like more details.

Wild aquatic birds, including gulls, terns, and shorebirds, and wild waterfowl, such as ducks, geese and swans are considered reservoirs or hosts for avian influenza A viruses.

Avian influenza is mainly spread by close contact between infected birds and healthy birds.  It can also be transmitted when birds come in contact with environments, equipment or materials (including water and feed) that have been contaminated with faeces or secretions from the nostrils or beak of infected birds.  If you have travelled overseas in the past two or three years, you may have seen warning signs such as that below from Cornwall, England.

bird flu sign, UK
Avian influenza sign, Cornwall, England 2022

This highly contagious viral infection can affect all species of birds both wild and domestic.  Cases have also been seen in mammals associated with bird mortality events including seals and sea lions.  What sets the most recent strain apart is the rapidity with which it spreads and the severity of the disease it causes among wild birds and mammals.

Avian influenza A viruses rarely infect people.  However, you may also have read about a human case of the current avian influenza A(H5N1) reported in Victoria, Australia recently.  The case was in a child who had returned to Australia from overseas in March.  There was a severe infection but the child has made a full recovery and there is no evidence of transmission in Victoria.  The chance of additional human cases is very low as avian influenza does not easily spread between people.


Current situation in New Zealand

Biosecurity New Zealand, a branch of the Ministry for Primary Industries, is responsible for assessing the risk, ensuring preparedness, and investigating and responding to any new pests and diseases arriving in New Zealand.

Biosecurity NZ have assessed the risk of HPAI arriving in New Zealand as low, being isolated from other land masses and does not have waterfowl (swans, geese, ducks and sometimes coots and grebes) migratory pathways, and New Zealand has never had a case of HPAI.

The DOC website has the following and much more information:

A variety of migratory shorebirds do return here and could bring avian influenza. The most numerous shorebirds are the bar-tailed godwit, red knot, ruddy turnstone and Pacific golden plover. The bar-tailed godwit flies directly from Alaska to New Zealand without stopovers.

Other species may visit estuaries along the Asian coastline, the Philippines and Australia on their annual migrations south from arctic Russia.

Seabirds such as Arctic and pomarine skuas arrive every spring and summer from the Arctic region. Arctic tern, little terns and common terns are also regular annual visitors to New Zealand, and many species of pelagic seabirds breed here after spending winter feeding in the Pacific and Southern Oceans.

DOC is working closely with Biosecurity NZ to ensure they are prepared to manage the effects on native species should the virus arrive.  They believe that HPAI could “affect colony nesting birds such as red and black-billed gulls, gannets, terns and other seabirds”, presumably including penguins, petrels, shearwaters, shags and prions, all found in colonies on the West Coast mainland or offshore islands.


What to look for and how to report possible cases of HPAI

Early detection is critical.  Signs of HPAI vary but indicators include: sudden death, tremors, weakness, paralysis, difficulty breathing and diarrhoea.

Do not touch or attempt to move any dead or dying wildlife.

Report groups of three or more sick or dying birds, marine mammals or other wildlife to the Biosecurity New Zealand Exotic Pest and Disease hotline: 0800 80 99 66.

Biosecurity New Zealand will take details and an incursion investigator will be in contact with you. Provide as much detail as you can, including:

Record a GPS reading or other precise location information.

Take photographs and/or videos of sick and dead birds.

Identify the species and estimate the numbers affected.

Note how many sick or freshly dead are present as well as total number present.

Follow Biosecurity New Zealand instructions for handling of sick or dead birds.


Other information

New Zealand’s main approach will be supporting strong, healthy populations of native wildlife at multiple locations as well as strong biosecurity and quarantine practices.  Vaccination may be a way to protect some core breeding populations and DOC is trailing a new vaccine that has been shown to be safe and effective in zoos in Europe.  Find out more about the trial here.

The spread of the virus is overlapping with environmental changes due to climate change, and the latter could increase the problem of the former.  In Chile, for example, the El Niño weather phenomenon had a strong impact last year on fish that birds rely on for food, placing more stress on animals and likely making them more susceptible to the virus.

For now, we must all have a watching brief, and be absolutely prepared.    The Trust is reviewing hygiene and other field protocols to ensure that we could not pick up or transmit the virus should we encounter it and has been acutely aware of the risk for some time, sharing this story in December 2022.  DOC is developing regional plans to be as prepared as they can be.

You can help by sharing this information with friends and family who walk our beaches.  Thank you.

Black-billed gull
Black-billed gulls, the most threatened gull on the planet. Photo: Steve Attwood