This species breeds on small, vegetated islands and rock stacks. It nests in colonies in burrows under grass, scrub or coastal forest, but occasionally breeds in rocky cavities (Marchant and Higgins 1990). The breeding biology of the species is very poorly known, but laying of eggs is believed to begin in early September, and chicks fledge from late January (Powlesland and Rickard 1992). Birds feed mostly on fish and some coastal krill (Marchant and Higgins 1990).

This species is a common and widespread species endemic to New Zealand. The largest colonies are found in the Three Kings group, Moturoa group, Motuharakeke (Cavalli Islands), north-west Chickens, Bream Islands, Mokohinau group, Channel Island, Mercury group, Ruamahuanui (Aldermen group) and Trio Islands, as well as on several other islands in the Cook Strait. Fledglings, and possibly some adults, move towards the east and south of Australia in February, but most remain near to breeding colonies throughout the year (Marchant and Higgins 1990, Powlesland and Rickard 1992).

Conservation Actions Underway
Polynesian Rat Rattus exulans has been eradicated from at least 14 island colonies in the last 15 years, as well as rabbits, goats and cats. A long-term experiment to establish a new breeding colony by the translocation of chicks was commenced in 1991 (Bell 1995). Pairs have since become established there, and breeding has occurred in consecutive breeding seasons since 1996 (Powlesland and Rickard 1992, B. D. and D. Bell in litt. 1999).