Migration windows highlighted in new research

Transcript

New research suggests changing wind patterns played a crucial role in helping sea-faring Polynesians colonise New Zealand.

The study out of Macquarie University in Sydney used evidence such as Pacific Ocean coral cores which indicate past sea surface temperatures to build a climate model looking back thousands of years.

The lead researcher Ian Goodwin told Mary Wilson that showed regular shifts in wind patterns that mean for periods of time it would have been much easier and faster to travel long distances in a canoe.

IAN GOODWIN:  The big difference here is if we compare this to the modern climate, if we were up in the Cook Islands and we want to make a passage back to in our yacht, in the modern era we've got access to weather information and weather forecasts out to almost ten days in some instances. So we can pick and chose the weather window to make these voyages. But if we go back a thousand years, Polynesians weren't as fortunate. And so they made these windows of opportunity for downwind sailing between central-east Polynesia and New Zealand. Where when there was prolonged  la nina like shifts in the climate where the trade winds extended further south and the westerly winds that are over New Zealand and particularly during the spring and winter, they were actually tracking further south towards Antarctica. And that meant that in fact voyaging canoes could in fact make downwind passages from central-east Polynesia down into New Zealand.

MARY WILSON: Because you had the wind behind you essentially?

IG: Absolutely and one of the differences between our work and previous notions if you like is that there's been a lot of debate about how these canoes would have had the capacity to sail up wind because if you take the modern climate pattern, you have to develop theories that enable Polynesians to sail against the adverse winds. Whereas we're saying that in fact when we've done this reconstruction, what jumps out at us is that there were these twenty year windows where they didn't need that. So these windows that opened up mean that voyagers could have made the trip to New Zealand in as little as a couple of weeks. Which is entirely plausible when you think that there's women and children, food and pigs and everything that they required for sustaining their society.

MW: It is fascinating stuff isn't it?

IG: It is and the last thing that I think is important is that the reconstruction shows that return voyaging from New Zealand back to central-east Polynesia was also plausible. In fact the windows that we've reconstructed indicate that even three way voyaging was possible. And of course this would be no surprise to any of the Maori in that the oral history accords multiple migrations. And it's entirely plausible that with these wind shifts that return voyages back to the Cooks or the Southern Australs could have been undertaken. But they may have been undertaken by grandchildren who have relied on the oral history of favourable winds and so on.

Ian Goodwin says radio carbon evidence suggests that Polynesians were able to settle on the sub Antarctic Auckland Islands in 1170 but civilisation died out there by 1300 AD due to a worsening climate.