About 500 kilometres south of Bluff, in a group of islands where the wind operates without apology and the vegetation grows sideways, a small flightless duck forages along the coastline after dark. The Auckland Island teal has no particular reason to fly. It has nowhere it would be safer, and several directions in which it would be considerably less so. Tētē kākāriki is one of three brown-plumaged teals endemic to the New Zealand region and the smallest of the group. Males show a green iridescence on the head and a dark chestnut breast. Females are uniformly dark brown. Both sexes carry white eye-rings that give them a look of permanent mild alertness. The wings are small and entirely useless for flight, reduced across generations in a population that evolved without mammalian ground predators and had no practical use for the metabolic cost of keeping wings functional. This is how island evolution tends to proceed: structures that cost energy and serve no purpose tend not to persist. On the islands where it survives, Adams, Enderby, Disappointment, and a few smaller islets, the teal forages along rocky coastlines and in peaty streams, moving into dense tussock and Olearia forest inland when the tide is out and the rocky platforms are exposed. The diet is opportunistic and coastal: amphipods, marine invertebrates, insects, and carrion from the petrel and mollymawk colonies that nest across the islands. Those seabird colonies provide a reliable supplement of organic material throughout the breeding season, which a bird with no means of leaving the island makes good use of. The main Auckland Island, far larger than any of the satellite islets, has no teal. Introduced cats and pigs eliminated the population there before any conservation response was possible. The remaining birds survive on islands where those introductions did not occur or have been subsequently removed, and where the terrain and weather are inhospitable enough to reduce human disturbance to near zero. The birds have no awareness of any of this, which is perhaps the most useful thing about them from a management perspective. Fewer than 600 birds are estimated across all surviving populations. The word stable appears in the current assessments, and on these particular islands at this particular moment it is probably accurate. What stability means for a flightless duck confined to a handful of subantarctic islets, in a group that includes a large island it cannot reach because predators are still there, is a kind of stability that requires very careful handling.