Excellent guided walks company on Rakiura-Stewart Island who run several guided walks around Rakiura-Stewart Island and Ulva.
I did the 3 hour walk on Ulva Island with Angie (the company founder). Wow! Angie knew so much from so many different aspects. She talked to me about me the island's (1) history, (2) flora, (3) fauna and (4) geology all the while keeping her super-tuned eyes and ears open to point out both the shy and cheeky birds floating around in the bush. I had thought of going on the self-guided tour which I'm sure would have been fun but also pretty sure I would not have seen 80% of the birds I saw with Angie. Highlights were seeing a very shy, very well-camouflaged Morepork, several Saddlebacks and jelly-like ferns (weirdly beautiful). Also fascinating to hear about Angie's experience being a member of the team that worked over several years to clear Ulva of predator animals to make it a safe haven for NZ's endangered birds. Highly recommend.