We can ID this gallinule as a South Island Takahe by its large size, mainly purplish-blue color, red frontal shield that extends to the forehead, huge conical red bill and stout red legs.
The South Island Takahe is a flightless bird that is endemic to New Zealand. It is the largest rail in the world. This bird was thought to be extinct. See the story in the next to last photo about how it was rediscovered.
The South Island Takahe is a new species to our Photographic Life List, which now stands at 739.