New Zealand’s endangered flightless birds are retreating to ‘moa graveyards’ – and it could save them from extinction

A new study has revealed striking and potentially ominous similarities between New Zealand’s endangered flightless birds and species that have already gone extinct.

Using computer simulations, scientists from the University of Adelaide have succeeded in reconstructing with some certainty the geographical range of extinct moa birds, and in particular their last habitats.

These so-called ‘moa graveyards’ are also home to the islands’ last flightless birds, including the iconic kiwi, as revealed in a new paper published by Nature Ecology and Evolution.

What happened to New Zealand’s moa?

New Zealand was once home to many more unique animals than it is today, including the moa.

These large, wingless birds grew up to 3.5 metres tall and were once found throughout New Zealand in a variety of habitats from forests to coastal dunes.

However, the arrival of human colonisation of the islands in the mid-13th century proved disastrous for moa, with the fossil record revealing that most of them were driven to extinction within two centuries of first human contact. This was due to a combination of habitat change, introduced species and hunting. The later arrival of Europeans only exacerbated these problems.

The flightless birds that survived these waves of human colonization still face similar threats today, with many of them considered endangered or critically endangered.

Mountain huts

This new study mapped the last habitats of six species of moa across New Zealand, using a combination of fossil evidence and precise computer simulations. It found that the last populations of these birds lived in the high, cold mountainous regions of the islands. These were far from ideal habitats, but they were the areas least affected by humans.

Interestingly, it is precisely in these suboptimal mountain areas that endangered but still surviving ratite species were found before large-scale modern conservation measures were introduced.

This similarity between extinct and current species is especially true for the most endangered species, such as the kākāpō and the takahē.

Repetitive patterns: living birds follow extinct moa

Evidence suggests that moas probably disappeared from higher quality lowland habitats first and that their population decline slows with increasing elevation and distance from the coast.

A similar pattern appears to apply to those species that have survived, with their once extensive ranges now restricted to the same small and suboptimal areas.

Even the most common of New Zealand’s eight remaining endemic flightless bird species, the weka and the North Island brown kiwi, have been recorded most frequently around these last moa reserves.

What does this mean for living ratites?

However, these findings are not necessarily a cause for despair about the fate of New Zealand’s ratites.

Thanks to intensive conservation efforts, some of the islands’ most iconic species, including the kākāpō, have been rescued from the brink of extinction. The situation for New Zealand’s birds now looks much better than ever.

A better understanding of historical extinctions, such as this research has provided, can only support and inform such conservation efforts by providing insight into the dynamics and forces behind such extinctions.

Knowing more about the behavior of the missing flightless birds may help scientists use better tools to help the remaining birds.

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