While domestic animals, sheep, deer and cattle abounded, the only animals we saw on the trail were birds. Isolated by the breakup of the primitive continent of Gowanaland, a jigsaw puzzle of South America, Africa, India, Antarctica, and Australia, and lacking natural predators, a bat the only native New Zealand mammal, birds rose to the top of the food chain.
Prehistoric birds larger than a human were abundant. Without predators they were free to forage on the forest floor and many lost the ability to fly ... a distinct disadvantage when the first settlers from Polynesia arrived. More destructive was the introduction of rabbits by early European settlers. They that did what rabbits do and in increasing numbers ate every blade of grass in sight. Ranchers were not happy ... introducing stoats, weasels on steroids, to eat rabbits. They also found ground dwelling birds a tasty diversion and proceeded to drive many toward extinction.
To date no one has suggested introducing anything to eat the stotes and feral cats and dogs that are also preying on ground dwellers. Perhaps there's hope for us after all :-)