A  Moa were nine species of now-extinct flightless birds endemic to New Zealand. The two largest species, reached about 3.6m in height with neck outstretched, and weighed about 230 kg. It is estimated that, when Polynesians settled New Zealand circa 1280, the moa population was about 58,000.

B  Moa belong to the order Dinornithiformes, traditionally placed in the ratite group. The nine species of moa were the only wingless birds lacking even the vestigial wings that all other ratites have. They were the dominant herbivores in New Zealand's forest, shrubland, and subalpine ecosystems for thousands of years, and until the arrival of the Māori, were hunted only by Haast's eagle. Moa extinction occurred around 1300–1440 ±20 years, primarily due to overhunting by the Māori.

C  Although moa skeletons were traditionally reconstructed in an upright position to create impressive height, analysis of their backbone structure indicates that they probably carried their heads forward in the manner of a kiwi. The spine was attached to the rear of the head rather than the base, indicating the horizontal alignment. This would have allowed them to graze on low vegetation, while being able to lift their heads and browse trees when necessary. This has resulted in a reconsideration of the height of larger moa.

D  Although no records survive of what sounds moa made, some idea of their calls can be gained from fossil evidence. The trachea (windpipe) of moa were supported by many small rings of bone known as tracheal rings. Excavation of these rings from articulated skeletons has shown that some moa exhibited tracheal elongation, that is, their trachea were up to 1 m long and formed a large loop within the body cavity. They are the only ratites known to exhibit this feature, which is also present in several other bird groups, including swans, cranes, and guinea fowl. The feature is associated with deep, resonant vocalisations that can travel long distances.