Buller's shearwater  (Puffinus bulleri)

Amazingly, the estimated population of some 2,500,000 birds breeds on just one small island group (Poor Knights Islands) off New Zealand, where it is restricted to two main islands, Aorangi and Tawhiti Rahi, and five other islets and stacks. In the non-breeding season, these masses migrate to the north Pacific Ocean, from Japan to North America, and are occasionally found off South America (6).

This marine, pelagic bird comes to shore only to breed (2), nesting in burrows, rock-crevices and ledges, often under dense vegetation (6).