Interesting. A 65,000 year isolated population. We can assume the Moa would go pretty quickly, followed by the Kiwi, the Tuatara, and any vulnerable or accessible bird population. After the first thousand years, any remaining birds would be the small agile flyers, skilled at avoiding humans.
So what are people eating? Fish, seals, and seabirds - sea protein. I expect that the seabirds would all be hunted out - from accessing their rookeries. Would the seals last? Maybe, maybe not.
It would be a feast and famine situation, with probably a thinly distributed population concentrating and descending on haul outs during breeding season. The key would be some way of storing the meat surplus.
Would there be an impetus to develop agriculture from the very meager botanical resources? Would any of the botanical resources be productive enough, regular enough and adaptable enough for agriculture?
Distinctive ethnic groups can emerge after only a few thousand years.
What sort of ethnicity would emerge with 65,000 years of isolation? Would we see pygmies? Would we see tall, slender, elfin giants with slow but incredibly long lives? Cattlemen with thick teeth, pot bellies, endlessly chewing their way through barely nutritious greens?