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.

Family/Sub-family Hydrobatidae

Species name author (Mathews, 1932)

Taxonomic source(s) Brooke (2004)

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.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

<50

unset

-

Yes

Range & population Oceanites maorianus was known only from putative fossil material¹, and from three specimens collected in the 19th century, two from the East Coast of the North Island New Zealand¹³, and one of unknown provenance, but suggested to be Banks Peninsula, South Island¹⁴, until one was observed and photographed off the Mercury Islands, North Island in January 2003⁴, and subsequently a flock of 10-20 were observed and photographed north of Little Barrier Island, North Island in November 2003⁵. Since then birds have been observed in the Hauraki Gulf each summer (October to April)¹⁰. It is thought to be a summer-breeding visitor to the Hauraki Gulf, although a nest site has yet to be found¹⁰. An bird apparently of this species was seen well and photographed off the southern end of New Caledonia in April 2008, which may represent a bird in, or migrating to its non-breeding range¹⁵. 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^7,8,9. A further three birds were caught and banded in late 2007 but these were not fitted with transmitters as they were not in breeding condition¹⁶.

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 slicks¹⁰. 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 year¹⁰.

Threats None are known, but the species could conceivably be impacted by introduced predators.

Conservation measures 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. Three birds captured in October-November 2007 were not fitted with transmitters as they did not appear to be in breeding condition. 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 measures proposed Continue ongoing work to clarify the taxonomic position of this taxon. Carry out further surveys at sea in the vicinity of the recent observations and elsewhere. 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 1. Holdaway (1999). 2. Oliver (1955). 3. Turbott (1990). 4. Saville et al. (2003). 5. Flood (2003). 7. Stephenson (2006). 8. Anon. (2006). 9. Stephenson (2006a). 10. Gaskin and Baird (2005). 11. Bourne and Jouanin (2004). 12. K. Baird and C. Gaskin in litt. (2004). 13. Bourne et al. (2004). 14. Medway et al. (2004). 15. Howell & Collins (2008). 16. Stephenson (2008).

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Tom Brooks (Conservation International), Stuart Butchart (BirdLife International), Ben Lascelles (BirdLife International), Andy Symes (BirdLife International)

Contributors Karen Baird (Kiwi Wildlife Tours), Chris Gaskin (Kiwi Wildlife Tours), Rod Hitchmough (Department of Conservation), Sav Saville (Wrybill Birding Tours), Paul Scofield (Canterbury Museum), Jean-Claud Stahl (National Museum of New Zealand), Brent Stephenson (Wrybill Birding Tours), Michael Szabo (Forest and Bird), Barry Weeber (Forest and Bird)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Andy Symes (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Oceanites maorianus. Downloaded from http://www.birdlife.org on 10/2/2010

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.

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