Moa are an extinct group of flightless birds formerly endemic to New Zealand. During the Late Pleistocene-Holocene, there were nine species. The two largest species, Dinornis robustus and Dinornis novaezelandiae, reached about 3.6 metres (12 ft) in height with neck outstretched, and weighed about 230 kilograms (510 lb) while the smallest, the bush moa, was around the size of a turkey. Estimates of the moa population when Polynesians settled New Zealand circa 1300 vary between 58,000 and approximately 2.5 million.
Moa
A comparison of a kiwi (l), ostrich (c), and Dinornis (r), each with its egg
Anomalopteryx didiformis skeleton
Fossil skeleton of the heavy-footed moa (Pachyornis elephantopus)
Flightless birds are birds that, through evolution, lost the ability to fly. There are over 60 extant species, including the well-known ratites and penguins. The smallest flightless bird is the Inaccessible Island rail. The largest flightless bird, which is also the largest living bird in general, is the common ostrich.
King penguins (Aptenodytes patagonicus). Penguins are a well-known example of flightless birds.
An Okarito kiwi (Apteryx rowi), also known as the rowi
Common ostrich (Struthio camelus). Ostriches are the largest extant flightless birds as well as the largest extant birds in general.
An extinct moa. Until the arrival of humans, New Zealand's only mammals were bats and seals, resulting in many bird species evolving to fill the open niches. While many of New Zealand's flightless birds are now extinct, some, such as the kiwi, kākāpō, weka, and takahē have survived to the present day.