DNA confirms it: the New Zealand storm petrel is officially back from the dead.

The tiny, enigmatic seabird was considered extinct for more than 150 years, meaning its comeback eclipses that of other "extinct" birds such as the takahe and Chatham Islands taiko.

It was rediscovered by birdwatchers Ian Saville and Brent Stephenson, near the Mercury Islands in the Hauraki Gulf.

SUPPLIED RESURRECTION: The tiny Storm Petrel bird is believed to have been extinct for 150 years.

"It was a complete fluke," Saville said. "We'd seen heaps and heaps of the common storm petrels, the white-faced storm petrels, and then I just saw this little black and white thing. It raced toward the boat, did a quick circle, raced off again and that was it."

That sighting was in January 2003. Since then the birds, in flocks of up to 40, have been seen every summer in the gulf, "almost within sight of the Sky Tower", Saville said.

But there has been confusion in the scientific community as to how and where the bird survived, and whether it is in fact a separate species, or just a more common species of storm petrel, with odd colouring.

Bruce Robertson of the University of Otago has just matched DNA from birds caught and released in the gulf, to tissue fragments from three museum specimens in England and France.

That confirms that the birds in the gulf are the same as those last seen in the 1800s, and that the New Zealand storm petrel is a distinct species. "I think that's pretty huge," Robertson said. He hopes this breakthrough will trigger official conservation funding. But the Department of Conservation says the bird will stay in the "data deficient" category – which receives relatively little funding – until scientists know where it breeds and how big the population is.

A group of bird enthusiasts from universities, Forest & Bird and DoC has been trying to answer those questions since the bird was first spotted. This month global conservation body BirdLife International gave the group $20,000 to continue the search.

The bird is thought to nest either in burrows, which would be as small as rat holes, or on cliffs. It comes ashore only during the breeding season, at night. So from January the group will be out on the water, using homemade net-guns to catch the birds and check them for "brood patches" – areas of plucked down, used to warm eggs – which would indicate they are breeding nearby.

TWO OTHER GREAT COMEBACKS

Takahe



"Extinct" for 50 years. Rediscovered in 1948 near Lake Te Anau, by Invercargill doctor and tramper Dr Geoffrey Orbell, who followed a set of strange footprints until he spotted four of the enormous blue birds.



There are still in the critically endangered category, with a population of about 250, including 110 in the Murchison Mountains.



Island taiko



Presumed extinct for nearly a century, the taiko (another kind of petrel) was rediscovered on the islands in 1978 by a team who spent more than a decade searching.

There are now thought to be fewer than 150 taiko left, including at least 15 breeding pairs.