In early 2008 I went up to see the release of the Pateke (Brown Teal) at the Tawharanui Sanctuary. This is on a peninsular and the park is managed by the ARC. Part of the end of the peninsular has been cut off with a large pest-proof fence and a wildlife sanctuary established behind this.
This is of critical importance as the pateke has had its numbers crash over the last century. By the mid-90s, numbers had dwindled to less than 2000 birds. The grim fact was wherever there was mustelids (stoats & ferrets) present, pateke would get exterminated by these introduced pests. That meant pretty much the pateke was doomed over its entire range.
A combination of captive breeding, allied to the establishment of these predator-free reserves, has allowed numbers to rebuilt somewhat.
As part of their return to Tawharanui, the local High School's kapa haka group put on a traditional welcoming show for the birds. It's this sort of thing that makes me optimistic about wildlife conservation :)