Pet dogs pose the biggest threat to our iconic national bird.

Fears our iconic national bird the Kiwi could be extinct within 50 years is worrying conservationists.

Kiwi numbers have been plummeting since the arrival of Europeans 200 years ago and the animal pests that came with them. But even in the past 20 years numbers have been dropping; declining from around 100,000 birds in 1998 to 73,000 in 2008 and just 67,550 in 2015.

Researchers estimate a decline of around two per cent a year - or 20 birds a week - is occurring and Ross Halpin of conservation charity Kiwis for Kiwi says at this rate the Kiwi could become extinct in the wild in 50 years.

He says while numbers of some species have stabilised and are even growing in sanctuaries and managed forests, wild populations are still highly at risk. Only about half of kiwi eggs hatch, and of those that do, about 90 per cent of chicks die in the first six months. Of the remaining 10 per cent, only about half make it to adulthood.

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"At current rates of decline, kiwi in the wild could become extinct in the next fifty years - but we won't let that happen," Halpin says. "The bulk of the population is now in the wild, but because we have island sanctuaries and predator-proof environments we wouldn't lose all of them. But basically that's the state of play."

It raises an interesting question: Would we still call ourselves Kiwis if the bird becomes extinct?

Halpin says there are some positive trends. Little spotted kiwi, once the most common subspecies, are now extinct on the mainland, but a managed population on Kapiti and other offshore islands is now growing, and its numbers are predicted to continue to increase over the next 15 years.

Active management, including 'creching' of baby kiwi, has led to increases in the numbers of rowi (the rarest species of Kiwi), the Haast tokoeka (a species found only in the South Island) and the Coromandel brown kiwi. But populations of the great spotted kiwi, and those found in Fiordland and Stewart Island are predicted to decline unless greater conservation measures are taken.
"The great spotted kiwi is the hardest for us in terms of management because we don't really know the true state of affairs - they live in such rugged terrain, in sparse populations over a vast area."

Halpin says the biggest problem is fewer than a quarter of New Zealand kiwi live in places where predators are controlled:"More than three-quarters of kiwi do not enjoy this level of protection and many populations continue to decline," he says.

While introduced predators are the biggest threat to young birds, dogs are actually killing the greatest number of adult kiwi. In an effort to overcome this problem Kiwis for Kiwi has partnered with the Real Pet Food Company, through its Natures Goodness brand, to educate dog owners about the risk they pose to kiwi - and how to mitigate it.

"Dogs are the biggest threat to adult kiwi, but there is something we can do about it which is the good news part of the bad news story," Halpin says. "Basically, if you keep your dog on a lead and have them aversion-trained, we can build wild kiwi populations."

Halpin says dogs are naturally inquisitive, and kiwi give off a scent which canines find particularly attractive. The combination of a curious dog and a flightless bird without a breastbone and prone to crushing is nearly always fatal.

"For New Zealanders who live in an urban environment it's not a worry - unless you go on holiday or go into the bush area where there are kiwi and let your dog run free. If you're going to a location like that keep your dog on a lead and consider aversion training.

"If you're a visitor to an area that's one thing, but if you live somewhere like Kerikeri, where you can hear the kiwi calling at night, you should be aware of this and do the responsible thing."