An interesting question you might ask, but one that lends itself to so many ideas and concepts.
NZ was once a place thriving with birds. Moa, as tall as modern houses once stomped around the forests and swamps that NZ once was. Haasts Eagle, with a huge wingspan of up to 8 metres once flew the skies.
Adzebill’s and other prehistoric birds used to live on the forests floors, much like the Kiwi still do. Huia filled the trees with beautiful music.
These birds are all extinct, but could you imagine if they still survived today? What would NZ be like if Moa still roamed the countryside? Haast’s Eagle’s flew away with screaming unattended babies? Adzebills taking huge chunks out of sleeping sheep…
What would NZ have looked like prior to European migration, even Maori migration? Who were the Maoriori and where are they now? Did anyone else discover NZ before the Maoriori or Maori did?
Is there still moose in the southwestern most corner of the South Island? Deer can swim across Tory Channel, surely Moose can swim across to the outer islands… Has anyone checked those?
What about the volcano’s that created a lot of NZ’s landscape? Was there anyone present when the first one went up? Would Auckland survive if the volcano’s became active again (would anyone south of the Bombay Hills care???).
NZ just lends itself to Speculative Fiction. I hope that I have given you food for thought.