Another rare and famous bird from New Zealand for our Lost Zoo – The Giant moa

Only very few birds are more famous than the flightless moa. The altogether 9 species (in 3 families and 6 genera) of this endemic New Zealand bird look similar to an ostrich, but moa are the only real wingless birds, lacking even the vestigial wings which all other ostriches, nandus, emus, cassowaries and kiwis have. Most of the moa species had the size of a large turkey. They measured with an outstretched neck 67-150 cm and weighted 30-75 kg. But two species were much larger and real gigantic, namely the Giant moa Dinornis robustus on South Island and Dinornis novaezelandiae on North Island. They reached about 3.6 m in height with neck outstretched and weighed about 230 kg. To create an impressive height and appearance, in museums moa skeletons are traditionally mounted in an upright position, but a detailed analysis of the skeleton and the head indicates that in fact the moa normally carried their head forward like the kiwis and used the long neck only to pick leaves in the higher bushes.

Moa were the largest and dominant herbivores in New Zealand's forest, shrub land and subalpine ecosystems. Although the Broad-billed moa (Euryapteryx curtus) and the Bush moa (Anomalopteryx didiformis) lived on the North Island as well as on the South Island, most other moa species were exclusive to only one island. The North Island giant moa (Dinornis novaezealandiae) and the Bush moa dominated on North Island in high rainfall forest habitat, which was similar to the South Island’s habitat. The other species on North Island preferred to inhabit drier forest and shrub land habitats and the Broad-billed moa (Euryapteryx curtus) have been found only in coastal sites around the southern half of the North Island.

The South Island has two main faunas, the high rainfall west coast beech forests that included the Bush moa and the South Island giant moa (Dinornis robustus) and the dry rain shadow forest and shrub land east of the Southern Alps that included the Heavy-footed moa (Pachyornis elephantopus), the Broad-billed moa, the Small moa (Emeus crassus) and the South Island giant moa. The two other moa species that existed on South Island, namely the Highland moa (Pachyornis australis) and the Forest or Upland moa (Megalapteryx didinus) might be included in a subalpine fauna, along with the widespread South Island giant moa.

Moa fed on a range of plant species and plant parts, including twigs and leaves taken from low trees and shrubs. The beak of the Heavy-footed moa was analogous to a pair of secateurs, and was able to clip the fibrous leaves and twigs up to at least 8 mm in diameter. Like many other birds, moa swallowed stones (gastroliths), which were retained in their muscular gizzards, providing a grinding action that allowed them to eat coarse plant material. These stones were commonly smooth, rounded quartz pebbles, but stones over 11 cm in length have been found too. The gastroliths of Giant moa could often contain several kilograms of stones.

Until the arrival of the Maoris in New Zealand at about 1280 the moa were the largest herbivores on the islands and their only natural enemy was the Haast's eagle (Harpagornis moorei). But the new invaders started immediately with the clearance of the dense forests and hunted the slow and flightless moa as food. Due to this overhunting and habitat destruction by the Maoris the moa were soon driven to extinction. At about 1445 all moa had become extinct, along with the Haast's eagle which had relied on them for food. But some scientists think that the Upland moa could survive in some remote areas perhaps until the end of the 18th century or even until 1887. However since that time definitely no moa has been again and it is hard to imagine that such a large bird could live hidden for such a long time.

Therefore we are extremely happy and proud that we could acquire one pair of this Giant moa for our Lost Zoo. Our visitors can see these birds near to the Auckland merganser. Observing these birds, most surprising is probably the large sexual dimorphism between the male and the female Giant moa. Females are 150% larger and 280% heavier than the males. Because of this large sexual dimorphism female and male birds were formerly classified as separate species until 2003. We hope that once in the future they will breed too. Their white egg measures up to 24x18 cm, has a volume of about 4.300 cm³ and is significant larger than an ostrich egg and about 90 times of a chicken egg. Instead of its large size it is very thin-shelled and therefore the most fragile of all avian eggs.

Executive Curator
JURGEN LANGE