Kiwi's giant lost cousin also loved the night-life

New findings show a close cousin of the kiwi was more like our national bird than researchers first thought. Photo / File

The kiwi's long-lost close cousin – which strangely happens to be an extinct giant bird that lived 11,400km away – loved the night-life as much as our national icon does.

A new study out today has found that, contrary to previous assumptions, Madagascar's three-metre-tall elephant bird didn't roam about in daylight like the moa, but was actually a nocturnal creature like the kiwi.

It marked the latest twist in the colourful but complex history of a group of flightless birds called ratites, which include our kiwi and the extinct moa.

To scientists, the elephant bird represented a dramatic change in the evolutionary history of the kiwi, whose ancestor was long thought to have flown in from Australia.

To the relief of those uncomfortable with the thought of our national bird being an Aussie immigrant, a landmark DNA-based study in 2014 found the kiwi was more closely related to the giant Madagascan native.

That same year, insights gleaned from DNA analysis also revealed how the moa was more closely related to South America's tinamous than its old bushmate, the kiwi, and concluded both moa and kiwi separately evolved to become flightless after their ancestors flew here.

Madagascar's elephant birds were hunted to extinction - just as New Zealand's moa were. Photo / Wikimedia Commons

In the latest study, US scientists were able to digitally reconstruct two elephant bird skeletons to reveal their eyesight was just as poor as the kiwi, making it likely they were also nocturnal.

The researchers, from the University of Texas at Austin, also found that the elephant bird had large olfactory bulbs like emu and kiwi, making it likely they had a heightened sense of smell to offset their poor eyesight.

Otago University palaeoecologist Dr Nic Rawlence said this was important as it demonstrated that decreased visual capacity was exclusively linked with flightless, nocturnal birds on islands where predators were few and far between.

Ultimately, both the moa and the elephant bird shared the same fate – extinction at the hands of human hunters.

Rawlence said the new insights were also another striking example of the "island rule" effect – which drove the evolutionary changes that occurred in birds restricted to islands.

This had also been observed in the extreme elongation of leg bones of an extinct native black swan, the Pouwa, which was only recently described by Rawlence and colleagues.