The kiwi's closest relative may not be an emu after all; new research suggests the creature is more closely-related to a Madagascan elephant bird.

Researchers have solved 150-year-old evolutionary mystery about the origins of flightless birds such as the ostrich and emu, a University of Adelaide news release reported.

The research suggests these types of birds may have had the ability to fly at once point in history. 

DNA extracted from the bones of two elephant birds showed a close genetic link with the kiwi, despite glaring differences in their "geography, morphology and ecology," the news release reported. 

"This result was about as unexpected as you could get," Kieren Mitchell, PhD candidate with ACAD, who performed the work, said in the news release. "New Zealand and Madagascar were only ever distantly physically joined via Antarctica and Australia, so this result shows the ratites must have dispersed around the world by flight."

The finding contradicts past research that linked the birds to the Australian emu and cassowary. 

"It's great to finally set the record straight, as New Zealanders were shocked and dismayed to find that the national bird appeared to be an Australian immigrant," ACAD Director Professor Alan Cooper, said in the news release. "I can only [apologize] it has taken so long!"

The researchers believe the ratite ancestors moved around the globe right after the extinction of the dinosaurs. 

"We think the ratites exploited that narrow window of opportunity to become large herbivores, but once mammals also got large, about 50 million years ago, no other bird could try that idea again unless they were on a mammal free island - like the Dodo," Cooper said. 

We recently found fossils of small kiwi ancestors, which we suggested might have had the power of flight not too long ago," co-author Flinders University's Dr Trevor Worthy, said in the news release. "The genetic results back up this interpretation, and confirm that kiwis were flying when they arrived in New Zealand.