A subantarctic seabird has brought the first case of potentially deadly H5 bird flu strain to the country – so here's what we know about the brown skua.
The subantarctic skua is a large, heavy-set brown gull-like bird with 1.5m broad pointed wings and a distinctive white outer-wing patch.
Yesterday, Biosecurity Minister Andrew Hoggard said the the highly infectious bird flu variant H5N1 that recently reached Australia was confirmed in New Zealand after a brown skua found on Petone Beach in Wellington tested positive.
Hoggard said H5 bird flu was a low health risk to the public as it rarely affected humans unless there was direct, close, and prolonged contact with large numbers of sick birds.
In an update today, Wellington Zoo confirmed to 1News the bird has since been euthanised.
Here's what to know about the brown skua:
As a highly infectious strain of H5N1 bird flu spreads around the world, natives such as the kākapō and takahē are being protected. (Source: 1News)
How might it have been infected?
Brown skuas were known to eat live animals and scavenge dead carcasses, according to the Department of Conservation's action plan for seabird conservation in New Zealand report.
"Because skuas are scavengers of carcasses, and are known to consume poison baits, care must be taken to prevent poisoning skua populations during future pest eradication operations," the DOC report said.
At sea, subantarctic skuas feed opportunistically on prey and debris on or just below sea-surface, but also force albatross and petrels to disgorge by high speed pursuit and strikes from above, according to online bird encyclopaedia New Zealand Birds Online.
"During the breeding season, subantarctic skuas generally specialise on one or a few avian prey species – variously penguins (eggs and chicks rather than adults), adults and fledgling petrels (particularly prions, storm petrels, diving petrels) and opportunistically other birds up to and including southern black-backed gulls."
Some brown skua associate with seal or sea lion colonies, feeding on dead pups, placentas, regurgitations and faeces.
Birds in non-migratory populations feed on goose barnacles and other marine invertebrates, when vertebrate prey are scarce or absent.
Where do they live, and how far do they fly?
The report said the birds were mostly found on offshore and outlying islands, and were dispersed widely over the Southern Ocean from the pack ice to 30C South. There were an estimated 7000 pairs of brown skua were living around the Southern Ocean.
Subantarctic skuas in the New Zealand subantarctic, like skua populations elsewhere, were present on their breeding grounds only during the summer, because their prey largely depart during the severe winters.
What preys on skuas?
"There is little evidence that adult skuas are vulnerable to mammalian predators except dogs and feral pigs," the DOC report noted.
At sea, there is the possible risk from fisheries "by-catch", particularly in areas beyond New Zealand Exclusive Economic Zone where pirate fishing may occur without mitigation techniques.
In the Chatham Islands and at locations around Stewart Island, the birds were most at risk of being shot by farmers.
What about other NZ birds or animals?
DOC said it had already begun vaccinating 300 core breeding birds from five of the country's most endangered birds – kākāpō, takahē, tchūriwat'/tūturuatu/shore plover, kakī/black stilt and kākāriki karaka/orange-fronted parakeet.
Animals including sealions were also at risk, French said, pointing to examples overseas where 90% of some populations had died.
Capital Kiwi Project Founder, Paul Ward, said the arrival of the H5 Avian Flu in New Zealand was not a surprise and no impact on the project’s wild kiwi was currently expected.
Hoggard warned pet owners not to allow their dogs or cats to come into contact with sick or dead birds.
"So if you’re taking your dog for a walk on the beach, don’t let it eat the dead seagull," he said.
Anyone who came across three or more sick or dead wild birds in a group should report this immediately to the exotic pest and disease hotline on 0800 80 99 66.
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