Moa
Dinornithiformes — nine species including Dinornis robustus
Moa were nine species of flightless birds endemic to New Zealand, the largest standing 3.6 m tall, driven to extinction around 1445 — approximately 150 years after Polynesian settlers arrived, making it one of the fastest megafaunal extinctions ever documented.
Updated 25 July 2026
- Number of species
- Nine, in six genera
- Largest species height
- About 3.6 m with neck extended
- Largest species weight
- Around 230 kg
- Wings
- None — no wing bones at all, unique among birds
- Human arrival in New Zealand
- Around 1280 CE
- Extinction
- Around 1445 CE — roughly 150 years later
Moa were New Zealand's answer to a continent with no mammals: nine species of flightless birds occupying the roles that deer, cattle and antelope fill elsewhere, ranging from turkey-sized to the giant moa, which reached 3.6 metres with its neck extended and weighed around 230 kg. They had no wings at all — not reduced wings, no wing bones whatsoever, unique among birds. They evolved alongside one predator, the enormous Haast's eagle. Polynesian settlers arrived around 1280 CE. Within roughly 150 years every moa species was gone, and the eagle that depended on them followed.
Key facts at a glance
- Nine moa species existed, from turkey-sized bush moa to the giant moa at 3.6 m tall and around 230 kg.
- Moa are the only birds known to have had no wing bones at all — total wing loss, beyond even the kiwi or ostrich.
- Females of the largest species were up to 150% taller and 280% heavier than males, one of the most extreme size differences known in birds.
- Extinction took roughly 150 years from human arrival — among the fastest megafaunal extinctions on record.
- Haast's eagle, the largest eagle ever known at up to 15 kg, preyed on moa and went extinct with them.
- New Zealand's remaining flightless birds — kiwi, kākāpō, takahē — face the same threat that finished the moa, in the form of introduced stoats, rats and possums.
How were nine species eliminated in 150 years?
Moa had every characteristic that makes a species vulnerable to a new predator, and they met an efficient one. They were large, providing enormous quantities of meat for relatively little effort. They were flightless and could not escape. They had no experience of ground-based predators, since Haast's eagle attacked from above and generated no useful defensive behaviour against hunters on foot. And they reproduced very slowly, laying small clutches with long incubation and taking years to reach breeding age. Archaeological middens from early Polynesian settlement contain moa bone in enormous quantity, along with vast numbers of eggshell fragments. Pacific rats arrived with the settlers and ate eggs and chicks. Forest was burned to clear land and drive game, destroying habitat across large areas of both islands. Modelling by Richard Holdaway and Chris Jacomb concluded that a founding human population of around 400 people could have eliminated all nine species within 150 years through hunting and egg predation alone.
The eagle that fell with them
Haast's eagle (Hieraaetus moorei) was the largest eagle that has ever lived, with females reaching around 15 kg and a wingspan of up to 3 metres, and it evolved specifically to kill moa. It struck from above at speeds estimated near 80 km/h, using talons the size of a tiger's claws to grip the pelvis and skull of prey many times its own weight. Māori oral tradition preserves accounts of a giant bird called the pouākai that could carry off people, and the eagle was certainly capable of killing a human. When the moa disappeared, Haast's eagle had no prey base — no other animal in New Zealand approached the size it was built to hunt — and it went extinct within the same window. It is one of the clearest documented cases of coextinction: remove a prey species and its specialist predator follows, whether or not anyone touches the predator.
Where it lived
New Zealand
What caused it
- 1 Hunting by the first Polynesian settlers
- 2 Egg predation by introduced Pacific rats
- 3 Forest clearance by burning
What this extinction teaches
A small human population with simple technology eliminated nine species in 150 years, and took a specialist predator with them. Extinction cascades through food webs — which is why protecting a keystone prey species protects a set of predators nobody is counting.
Still here — for now
Still facing the same pressure: Kākāpō
New Zealand's surviving flightless giant — the world's heaviest parrot, flightless, slow-breeding, ground-nesting, and defenceless against the introduced stoats and rats that replaced human hunters. It survives only because every single bird is individually monitored on predator-free islands.
IUCN status: Critically Endangered
Did you know
Moa gizzard stones — smooth quartz pebbles the birds swallowed to grind food — are still found in New Zealand today, sometimes several kilograms of them in a single spot marking where a bird died 600 years ago.
Moa: frequently asked questions
When did moa go extinct?
How big were moa?
What killed the moa?
What is the moa's closest living relative?
Did moa really have no wings?
Sources
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