How Kiwi Arrived

Research into the kiwi’s DNA suggests the species are more closely related to the Australian emu rather than the now extinct moa.  

This suggests that kiwi developed outside New Zealand, after it separated from Gondwana, and migrated here later.  It is thought their ancestors arrived about 60 million years ago.

Just how that journey was made remains a mystery. Fossil records are a useful tool to help decipher what happened, but the oldest kiwi fossil (a leg bone found on the coast near Bulls) is only one million years old.  That is a mere blip in time compared with the 50- to 80-million year-old fossils needed to tell the story.

Two possible explanations for kiwi’s arrival are...

Walking to New Zealand

As tectonic plates in the earth’s crust move, islands are pushed up above the sea and submerged. Over the eons, a string of islands have come and gone between New Caledonia and Northland, and this may have provided a route from Australia to New Zealand

Flying here

Of all today’s ratites, none can fly. Those who support the view that ratites share a common flightless ancestor, argue that means kiwi could not have flown here.

Another argument against kiwi flying here is the theory that its ancestor was much bigger than today’s bird. It is based on the size of the kiwi egg, which should theoretically be laid by a bird two or three times larger – closer to a cassowary in size.  A bird that size would have been much too big to fly across the Tasman Sea, even millions of years ago when it was much narrower.