[3] Moa are grouped together with emus, ostriches, kiwi, cassowaries, rheas, and tinamous in the clade Palaeognathae.

[3] The crested moa was endemic to the South Island of New Zealand, where it occupied the high altitude sub-alpine forests in the North West, particularly in the Nelson area.

While their remains have occasionally been found together, the heavy-footed moa generally preferred warmer and drier lowland areas.

[8][10] The robust beak with a pointed tip, sturdy jaws, together with large numbers of gizzard stones suggests the diet of Pachyornis was high in fibrous plant material such as branches of trees and shrubs.

[8][11] In 2012 however radiocarbon dating of crested moa remains from Bulmer Cavern showed that the specimen died between 1396 and 1442 AD, over 100 years after humans first settled on the Island.