• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Justification of Red List category
This species is categorised as Vulnerable on the basis that it is estimated to have a very small population and breeding range. However, there are very few data on this species and on the potentially threatening processes operating at breeding colonies; were more information available this might lead to a category change.

Population justification
The population size is estimated not to be above a few hundred by BirdLife International (2000), based on analyses of recent records and surveys. It is placed in the band 250-999 mature individuals here, equating to 375-1,499 individuals in total, rounded here to 350-1,500 individuals.

Trend justification
There are no data; however, there is little reason to suspect a decline.

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.

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

The species is poorly known and due to limited data on nesting range, the potential impacts of current and future threats are not readily assessed. At present, introduced non-native mammals are thought to pose the greatest threat to the species. Despite breeding on high, inaccessible mountains, all of the relevant islands in the species’s suspected breeding range host rats Rattus spp., cats Felis catus and dogs Canis familiaris. Rats have been recorded to at least 900m altitude on Kolombangara and potentially pose a serious threat to this burrow-nesting species (Buckingham et al. 1995). Cats have been identified as an even greater threat, and are present in the mountains where the species is believed to breed, and while their true extent is unknown, predation on adults is likely to be severe where ranges overlap (G. Dutson in litt. 2007). The impact of dogs is understudied and the smaller range of this invasive species is unlikely to have as severe an effect as cats and rats. Another long-term threat is posed by the ongoing logging of areas where the species is suspected to nest (C. Collins in litt. 2011). On Bougainville, where the species is believed to breed, commercially viable deposits of metals occur, however no mining has taken place for nearly three decades due to political conflict and local opposition. However, plans for independence from Papua New Guinea apparently include the intent to recommence extractive industries to expand the economy. 

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.

27 cm. Small, dark brown, rather fluttering shearwater. Often entirely sooty-brown except narrow, silvery underwing bar. Some have white bellies. Long, slender bill is notable. Similar spp. Plumage similar to Short-tailed Shearwater P. tenuirostris but it has short, stubby wings, weak flight and longer bill. Differs from Audubon's Shearwater P. lherminieri in its browner plumage, dark body and less white on underwing. Voice Silent at sea, unknown on breeding grounds. Hints Frequently seen from inshore boat journeys around the islands of Kolombangara and Bougainville, often in mixed-species fishing flocks.

Text account compilers
Bennett, S., Dutson, G., Fjagesund, T., Calvert, R., O'Brien, A., Stattersfield, A., Symes, A., Taylor, J.

Contributors
Dutson, G., Mahood, S., Collins, C., Scofield, P., Bourne, W., Brooke, M.

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Recommended citation
BirdLife International (2024) Species factsheet: Heinroth's Shearwater Puffinus heinrothi. Downloaded from https://datazone.birdlife.org/species/factsheet/heinroths-shearwater-puffinus-heinrothi on 23/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 23/11/2024.