Species

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Justification
Previously assumed to have been Extinct following the lack of records since three specimens were collected in the 1800s, this species was spectacularly rediscovered in 2003, with multiple annual records subsequently. Although there is very little information on which to base an assessment, the species has been precautionarily classified as Critically Endangered on the basis of an extremely small population which could be susceptible to the impacts of introduced predators. Further observations and information may well lead to a revision of the criteria triggered, and possibly the category to which it is assigned.

Taxonomic source(s)
Brooke, M. De L. 2004. Albatrosses and petrels across the world. Oxford University Press, Oxford.

Taxonomic note
Oceanites maorianus (Brooke, 2004) endemic to New Zealand, was not listed by Turbott (1990) as previously believed to be extinct.

Identification
17 cm. A medium-sized storm petrel with noticeably large head, long legs and long feet, the latter projecting well beyond the square tail. Head, neck and upperparts blackish-brown except for pale carpal bar, white rump and uppertail coverts. Breast blackish-brown grading into blackish streaks on white belly, flanks and undertail coverts, but the amount of streaking highly variable. On the dark underwing, there is a pale central patch. Bill, eye, legs and feet black. Toes extend well beyond the tail in flight, which is swift-like with alternating flapping and glides. Similar spp. Black-bellied Storm Petrel Fregatta tropica, much larger, lacks the streaked flanks, generally has a black belly stripe and has broader, more rounded wings. White-bellied Storm Petrel Fregetta grallaria lacks any streaking on the normally white upper breast and belly (some populations have dark bellied forms) and also has broader, more rounded wings, and toes do not project beyond tail. Wilson's Storm Petrel Oceanites oceanicus is all dark ventrally, but does have a similar, but not the same, flight progression.

Distribution and population
Oceanites maorianus was known only from putative fossil material (Holdaway 1999), and from three specimens collected in the 19th century, two from the East Coast of the North Island New Zealand (Bourne et al. 2004), and one of unknown provenance, but suggested to be Banks Peninsula, South Island (Medway et al. 2004). However, one individual was observed and photographed off the Mercury Islands, North Island in January 2003 (Saville et al. 2003), and subsequently a flock of 10-20 was observed and photographed north of Little Barrier Island, North Island in November 2003 (Flood 2003). Since then birds have been observed in the Hauraki Gulf each summer (October to April) (Gaskin and Baird 2005). It is thought to be a summer-breeding visitor to the Hauraki Gulf, although a nest site has yet to be found (Gaskin and Baird 2005). Up to three were reported on pelagic trips off New South Wales, Australia in March and April 2010 (Ramsay 2010). In 2005-2006, four birds were caught at sea, with DNA samples collected and transmitters attached, although this has not yet led to the discovery of breeding sites (Anon. 2006, Stephenson 2006a,b). A further three birds were caught and banded in late 2007 but these were not fitted with transmitters as they were not in breeding condition (Stephenson 2008). A review of previous petrel sightings and specimens suggests the New Zealand Storm-petrel may have been present in the Hauraki Gulf for at least the past four decades (Stephenson et al. 2008).

Population justification
The population is assumed to be tiny (fewer than 50 individuals and mature individuals) based on the small number of records since 2003. Most have been of small numbers, but flocks of 10-20, 11 and 10-30 birds have been recorded.

Trend justification
The population may well be decreasing owing to the impacts of alien invasive predators, but this remains speculation until the breeding grounds are discovered.

Ecology
The species seems to occupy warmer waters which move into the Hauraki Gulf during summer. It probably feeds on small crustaceans and plankton associated with this water, and it is readily attracted to chum slicks (Gaskin and Baird 2005). The breeding season is possibly late November (egg-laying) through to May (fledging). It is thought to be migratory owing to its absence from Hauraki Gulf from June to September each year (Gaskin and Baird 2005).

Threats
No immediate threats are known, but the species could conceivably be impacted by introduced predators.

Conservation actions underway
The species may have already benefited from rat-eradication programmes on offshore islands. In the summer of 2005-2006, four birds were captured, and attempts made to follow them to their breeding grounds with the aid of radio telemetry. This was unsuccessful, and further attempts to capture birds in November and December 2006 failed (Anon. 2006, Stephenson 2006a,b). Three birds captured in October-November 2007 were not fitted with transmitters as they did not appear to be in breeding condition (Stephenson 2008). Location of the breeding grounds of this species is critical in determining population size and providing protection for the site, and searches are underway.

Conservation actions proposed
Continue on-going work to clarify the taxonomic position of this taxon. Carry out further surveys at sea in the vicinity of the recent observations and elsewhere, and continue searches for the breeding grounds, adopting a variety of suitable methods. If it is found to breed on an island with introduced predators, eradicate these as an urgent priority.

References
Oliver, W. R. B. 1955. New Zealand birds. Reed, Wellington, New Zealand.

Turbott, E. G. 1990. Checklist of the birds of New Zealand. Ornithological Society of New Zealand, Wellington.

Holdaway, R. N. 1999. Introduced predators and avifaunal extinction in New Zealand. In: MacPhee, R.D.E. (ed.), Extinctions in near time: causes, contexts and consequences, pp. 189-238. Plenum Press, New York.

Bourne, W. R. P.; Jouanin, C. 2004. The origin of specimens of New Zealand Storm Petrel (Paeleornis maoriana Mathews, 1932). Notornis: 57-58.

Gaskin, C.; Baird, K. 2005. Observations of black and white storm petrels in the Hauraki Gulf, November 2003 - June 2005: were they of New Zealand Storm Petrels? Notornis 52(4): 181-194.

Anon. 2006. New Zealand Storm-petrel - in the hand! Birding World 19: 44.

Stephenson, B. 2006. New Zealand Storm-petrels captured in the Hauraki Gulf. Forest and Bird 319: 7.

Stephenson, B. 2006. First transmitters fitted to New Zealand Storm Petrels. Southern Bird: 8-9.

Bourne, W. R. P.; Jouanin, C.; Catto, J. V. F. 2004. The original specimens of the New Zealand Storm-petrel. Notornis 51: 191.

Medway, D. G. 2004. The place of collection of the original specimens of Pealeornis maoriana Mathews, 1932. Notornis 51: 58-59.

Stephenson, B. 2008. Ghost birds. Forest and Bird: 38-39.

Howell, S. N. G.; Collins, C. 2008. A possible New Zealand Storm Petrel off New Caledonia, southwest Pacific. Birding World 21(5): 207-209.

Stephenson, B. M.; Flood, R.; Thomas, B.; Saville, S. 2008. Rediscovery of the New Zealand Storm Petrel (Pealeornis maoriana Mathews 1932): two sightings that revised our knowledge of storm petrels. Notornis 55(2): 77-83.

Flood, B. 2003. The New Zealand storm-petrel is not extinct. Birding World 16(11): 479-482.

Saville, S., Stephenson, B., Southey, I. 2003. A possible sighting of an 'extinct' bird - the New Zealand storm-petrel. Birding World 16(4): 173-175.

Text account compilers
Anderson, O., Benstead, P., Bird, J., Brooks, T., Butchart, S., Calvert, R., Lascelles, B., Symes, A., Taylor, J.

Contributors
Baird, K., Gaskin, C., Hitchmough, R., Saville, S., Scofield, P., Stahl, J., Stephenson, B., Szabo, M., Weeber, B.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2013) Species factsheet: Oceanites maorianus. Downloaded from http://www.birdlife.org on 19/06/2013. Recommended citation for factsheets for more than one species: BirdLife International (2013) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 19/06/2013.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

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