Room 2 of Omakau School, Central Otago, asks :-
We have bones and a letter re a moa called Dinornis torosus. What is known of this species of moa?
John Darby, a retired zoologist now at Wanaka and the principal editor and a contributor to the “Natural History of Southern NZ” responded.
Sometime in 1969 the McNight family of Cairnhill Station in Becks in Central Otago found some Moa bones and took them to the Otago Museum for identification. I wrote to the McNights in October 1969 and suggested that the bones were of a Moa species then known as Dinornis torosus. It appears that my letter was framed by the McNights and it together with the Moa bones was presented to the Omakau School and now, in a rather nice touch, almost 43 years later, students of room 2 would like to know more about D torosus.
Back then; scientists considered that there were 23 species of Moa, a great improvement on estimates made in the late 1800s and early 1900s of sixty-four species. Since 1969 things in the Moa world have changed dramatically. Using ancient DNA extracted from bones, scientists have made some startling discoveries the most significant being that instead of the males and females being the same or very similar size, female Moa of the same species as the male were up to 2-3 times bigger than the male. And that has changed things dramatically. Now there are only nine species, 2 of which are only found in the North Island, 2 that are found in both north and South Islands and five species found only in the South Island.
My original identification of D torosus suggests that it would now be called Dinornis robustus or the South Island Giant Moa. It is this species that is considered to be the largest bird that ever lived with females standing close to 2 metres high and weighing up to 242kg and males up to 85kg. We believe moa lived to about 50 years of age.
D robustus was widespread throughout the South Island, (the largest moa egg 240 x 178mm was laid by this species and was found at Kaikoura). Research by Dr Jamie Wood on the diet of this moa from a crop found at Scaifes Swamp close to Glendu Bay near Wanaka indicated that D robustus browsed on twigs, leaves of trees, shrubs, fruits, herbs and lianes and these included miro, putaputaweta, swamp lawyer, kaikomota and cabbage tree. Robustus would have travelled widely, through dense beech forest and particularly on forest edges. It, with all the other species of Moa died about 500 years ago, mostly due to hunting and the loss of much of their habitat due to fires.