Justification This species qualifies as Critically Endangered for several reasons. It has undergone a an extremely rapid historical decline over three generations (60 years). It has an extremely small population and, although the long-term reduction in numbers may have begun to stabilise, it is premature to assume that there is not a continuing decline. Furthermore, it is restricted to just one extremely small location.

Family/Sub-family Procellariidae

Species name author (Giglioli & Salvadori, 1869)

Taxonomic source(s) Brooke (2004), Sibley and Monroe (1990, 1993), Turbott (1990)

Identification 38 cm. Medium-sized, dark brownish-grey and white petrel. Mostly uniform brownish-grey head, neck, upper breast, upperparts, upperwing, tail. White lower breast, belly, undertail. Brown underwing, paler under primaries. Black bill. Pink legs. Feet pink proximally, black distally. Similar spp. Phoenix Petrel P. alba is smaller, more brown. Atlantic Petrel P. incerta is bulkier with brown undertail. Voice Calls or-wik, si, si, si and orr.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

120 - 150

decreasing

1,960,000 km²

Yes

Range & population Pterodroma magentae was rediscovered in 1978 in the south-east corner of Chatham Island, New Zealand, 111 years after it was first collected at sea¹. Its prevalence in Moriori middens suggests it was once common and has undergone a massive historical decline¹². In 1994, only four breeding pairs were known, although it was suspected that others remained undetected, and that the population was still declining at this time. In 2004, surveys indicated a population of 120 individuals, including 15 breeding pairs^9,10,11. Just 16 chicks were known to have fledged from 1987-1988 to 2000⁶, but in 2002 a total of seven chicks were fledged⁷. By 2006, there were 35 active burrows, c.25 breeding pairs, and 11 known chicks, taking the total number of chicks fledged since 1987 to 63¹⁴, and in 2008 15 pairs hatched a record 13 eggs²⁰. Inshore waters (1-2 km offshore from the colony) around Otawae Point are thought to be important for non-breeders visiting the colony and during courtship at night¹². Its range at sea is probably eastwards into the Pacific Ocean to waters off western South America¹³ and south of the island, with one bird seen at sea in December 2004 between the Chatham Islands and the Bounty Islands^6,13. In 2007, eight chicks were successfully moved from the Tuku Nature Reserve in the south of Chatham Island to the nearby Sweetwater Conservation Covenant, where they successfully fledged¹⁷, and the process was repeated for all 13 chicks in 2008²⁰.

Ecology: It breeds in a fragmented colony under dense forest³, 4-6 km inland. Burrows are up to 5 m long and breeding takes place from September to May²⁰. Males occupy burrows for 1-3 years before pair formation and breeding; non-breeding females rarely visit the colony¹². Its diet is not well known, but includes squid³. Recent ringing returns show that males return to the colony aged 4-5 years, females at 6-9 years, and first breeding is attempted at around 10 years^{2, 12}. The pairs form a life-long bond, one egg is laid per year, incubated by both parents, and fledging chicks climb trees from which they launch themselves to fly out to sea²⁰.

Threats Introduced species (particularly three rat species, pigs, cats, Weka, possums and stray dogs^12,16) take eggs, chicks and adults, or compete for, destroy or cause the desertion of burrows. Flooding of burrows may also lower breeding success⁶. Loss of forest habitat from accidental fire represents a threat⁸. Historically, the pastoralisation of Chatham Island probably caused the final destruction of the major colonies. Prior to 1900, local Moriori and Maori caught thousands of chicks for food^1,14.. Molecular analysis has found that, while the sex-ratio is approximately even in petrel chicks and breeding adults, 95% of non-breeding adults are male. This suggests that low population levels may be causing unpaired male birds difficulty in attracting a mate, as their calls are too spread out to attract the infrequent females which pass by¹⁹.

Conservation measures underway Ten years of intensive searching led to its rediscovery in 1978, but no burrows were found¹. In 1987, radio-transmitters attached to the tail-feathers of birds finally led to the discovery of three burrows⁵, and trapping for predators was immediately commenced⁴. Ongoing searches located only three more burrows, but in 1999, at least 17 new burrows were discovered⁶. Breeding areas have been protected by the Tuku Nature Reserve¹⁵. Predator control was intensified in 1996¹². All burrows are monitored for breeding attempts^2,4 and infra-red cameras are deployed at each nest to monitor activity and identify predators¹⁶. Egg- and chick-rearing trials have been undertaken on the closely-related Grey-faced Petrel P. macroptera, and its diet analysed, to develop methods for captive rearing of P. magentae⁶. In 2006, a 3 ha safe colony with predator-proof fence, wooden burrows, and playback sound system was established at the Sweetwater Secure Breeding Site, and chicks transferred here prior to fledging to form a new colony^{6 14}. Eight chicks were successfully moved and fledged here in April-May 2007, as were a further 13 in 2008, and all known chicks will be moved there over the next three years to form a nucleus of a new population¹⁷. The Chatham Island Taiko Trust was established in 1998 to provide legal status to the continuing work¹⁷. The 1200 hectare South Chatham Covenant, adjacent to the Tuku Nature Reserve and containing one known cluster of burrows, is now fenced, and is currently being surveyed to determine its actual area: as at Sweetwater ownership will remain with the existing landowners but the Covenant will ensure protection in perpetuity²⁰. The 2011 target is to establish a self-sustaining population of at least 250 individuals.

Conservation measures proposed Continue ground searches and telemetry to locate further burrows. Continue night surveys for prospecting birds and to collect data on survival. Continue to use study holes at all active nest burrows to enable active intervention if chicks are undernourished or abandoned. Continue sustained predator and herbivore control. Continue to study the species's ecology, including at-sea distribution (with use of satellite tags), to identify threats. Consider maintenance of genetic diversity when planning future conservation actions¹⁸.

References 1. Crockett (1994). 2. Department of Conservation (1999). 3. Heather and Robertson (1997). 4. Imber et al. (1994a). 5. Imber et al. (1994b). 6. Taylor (2000). 7. M. Ogle in litt. (2002). 8. Aikman et al. (2001). 9. Hilhorst (2000). 10. Brooke (2004). 11. G. Taylor in litt. (2005). 12. Imber et al. (2005). 13. Howell (2005). 14. Stephenson (2006b). 15. Stephenson (2006a). 16. Johnston et al. (2003). 17. Department of Conservation (2007). 18. Lawrence et al. (2008a). 19. Lawrence et al. (2008b). 20. C. Miskelly in litt. (2008).

Further web sources of information

Alliance for Zero Extinction (AZE) species/site profile. This species has been identified as an AZE trigger due to its IUCN Red List status and limited range.

New Zealand Govt - Dept of Conservation - Recovery Plan

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Ben Lascelles (BirdLife International), Rachel McClellan (BirdLife International), John Pilgrim (BirdLife International), Andy Symes (BirdLife International)

Contributors Colin Miskelly (Department of Conservation), Mike Ogle (Department of Conservation), Graeme A. Taylor (Department of Conservation)

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

Recommended citation BirdLife International (2009) Species factsheet: Pterodroma magentae. Downloaded from http://www.birdlife.org on 9/2/2010

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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