Biogeographic Theory and the Number and Habitat of Moas
From the relationship of the number of bird species to land area in New Zealand, the expected number of moa species is about 8 to 12. Of these, half should have lived in forest and half in open habitats. This may help to explain the uneasiness biogeographers have felt with 28 described species of moas, and the question of whether they were forest birds or not.