The story
Moa were wingless birds of New Zealand, with nine known species in the order Dinornithiformes. The largest, Dinornis, stood about 2 metres at the back and up to 3.6 metres with its neck raised, and females were heavier than males, up to about 230 kilograms. Moa had no wings at all, not even tiny bones, which makes them unique among birds. They browsed on shrubs and leaves, and the only predator that could take an adult was Haast's eagle, a bird with a wingspan of about 3 metres. Despite their size, moa were most closely related to the small tinamous of South America, not to ostriches.
Polynesians reached New Zealand around 1250 to 1300 CE and hunted the moa. Radiocarbon dating of bone and eggshell by Richard Holdaway and colleagues in 2014 and by Perry and colleagues the same year indicates that all species were gone within about 100 to 150 years of settlement, by about 1400 CE or soon after. Moa had slow growth and breeding, so overhunting, along with forest burning and predation by introduced dogs and rats, was enough to end them. Haast's eagle disappeared soon after, since it lost its prey. The extinction is one of the best-documented human-caused ones, and it happened in the recent past.
Why it mattered
- The moa case shows how quickly people could eliminate large, slow-breeding birds on an isolated island.
- It left forests without their largest browser, and some tangled New Zealand shrubs may owe their form to browsing by moa, a hypothesis.
- Moa bones from swamps and caves record an island fauna that evolved with no land mammals at all.
Sources
- South Island giant moa New Zealand Birds Online
- Second study confirms moa's rapid extinction caused by early settlers Science Media Centre NZ
- An extremely low-density human population exterminated New Zealand moa Nature Communications (PMC)
Community notes
Loading notes…