The only observations of this species ashore, and a comparison with closely-related species, suggest that it breeds in high mountains.

Puffinus heinrothi is known from the Bismarck Archipelago and the seas around Bougainville in Papua New Guinea and Kolombangara in the Solomon Islands (Coates 1985, 1990, Buckingham et al. 1995). The few historic specimens are from Watom near New Britain suggesting breeding there, but there have been no recent records from this island and only a few records of up to 20 birds in the Bismarck seas, ranging to Madang on the north coast of New Guinea (Coates 1985, 1990, Bailey 1992, Clay 1994, Hornbuckle 1999a). Two individuals, one recently fledged, caught inland on Bougainville indicate it may be breeding there (Hadden 1981). This is supported by a number of recent observations in the seas around Bougainville, including one flock of 250 birds between Buka and Kieta (Coates 1985, 1990), and a recent sighting of 11 birds off Central Bougainville. It undoubtedly breeds on Kolombangara, where small groups form in the evening offshore before flying inland (P. Scofield in litt. 1994, Buckingham et al. 1995, Gibbs 1996, Onley and Scofield 2007). It presumably also breeds on the nearby island of Rendova where one bird was seen flying out of the mountains at dawn (M. Iles verbally 1998). It is believed to be a relatively sedentary species and its total population may not be above a few hundred. The population trends are unclear; the only suggestion of any decline is the absence of recent records around Watom.

Conservation Actions Underway
None is known.

Conservation Actions Proposed
Assess the timing of breeding seasons and best survey techniques at Kolombangara. Survey all mountainous islands within its range at dawn and dusk for breeding birds. Survey numbers at sea off Bougainville. Monitor numbers off Kolombangara. Assess the presence of introduced mammals in suspected breeding grounds. Investigate breeding grounds for dead birds and other evidence of predation. If appropriate, initiate control measures against introduced mammalian predators.