Moa

How big were moa?

Some moa were enormous. The giant moa was one of the biggest birds ever known. It was more than three metres tall and weighed about 250 kilograms, (as big as Big Bird from Sesame Street!)

There were smaller moa too, some only half a metre tall and about as big as turkeys. Female birds were much bigger than male birds which makes it hard to work out exactly how many different species there were. Currently it is thought there were 10 species of moa.

Why did moa become extinct?

Moa were the biggest land animals in New Zealand and would have been a very useful food for maori. Because they couldn’t fly they were easy to catch, especially the chicks which dogs (kuri) would have eaten. Scientists think that moa were eaten to extinction by 1500.

They aren’t the only extinct New Zealand birds. There are many others - rails, adzebill, wrens, eagle, etc.

Why were moa flightless?

Like their relations, the flightless emu, ostrich and kiwi, the moa evolved from birds that could fly. Flying has lots of advantages but it has disadvantages too: it uses heaps of energy, you can’t grow too big and heavy (or you wouldn’t get off the ground!) and it’s harder for little animals to stay warm than it is for bigger animals.

Moa ate leaves, shoots and berries and there were lots of these near the ground. They didn’t need to fly to find food and on the forest floor they were safer from their only enemy, the gigantic Haast’s eagle. So over millions of years, the moa’s wings became smaller, their bodies bigger and heavier and they strode through the forest instead of flying.

But when people and dogs arrived the moa had new enemies that they couldn’t escape, enemies who would drive them to extinction in a few hundred years.

How do we know about moa?

Scientists have found their bones buried in swamps, sand dunes and in maori middens (rubbish heaps).Some moa had accidents. They fell into holes in limestone country and their skeletons lie there, waiting to be discovered by cavers.