Pterodroma cervicalis 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Procellariiformes Procellariidae

Scientific Name: Pterodroma cervicalis
Species Authority: (Salvin, 1891)
Common Name(s):
English White-necked Petrel, White-naped Petrel
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Lynx Edicions BirdLife International.
Taxonomic Notes: Pterodroma cervicalis (Sibley and Monroe 1990, 1993, Brooks 2004) was split into P. cervicalis and P. occulta by Imber and Tennyson (2001) and Christidis and Boles (2008), largely on the basis of the latter's smaller size and relatively longer tail, but this treatment is not followed by the BirdLife Taxonomic Working Group because athough there are a few other minor plumage differences, occulta is not known to differ vocally or in the timing of its breeding season from cervicalis, and it is therefore felt premature to accord occulta specific status.

Identification information: 43 cm. Large, grey-and-white petrel with distinctive white hindneck. Black cap extends to below eyes. White band extends from throat around hindneck. Grey upperparts, upperwing, with black "M" across wings. May have grey half-collar across upper breast. White underparts. White underwing with narrow, black trailing edge, black tip, wider black leading edge distal to carpal joint, short, bolder black bar extending towards centre of wing from joint. Similar spp. Distinguished from Juan Fernandez Petrel P. externa by stronger cap contrast, bolder black marking at leading edge of underwing distal to carpal joint. P. externa has grey nape, but some individuals become almost as white-necked as P. cervicalis.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Carlile, N., Garnett, S., MacAllan, I., Taylor, G. & Tennyson, A.
Facilitator/Compiler(s): Anderson, O., Benstead, P., Calvert, R., McClellan, R., Taylor, J. & Temple, H.
This species qualifies as Vulnerable because it has a very small range, on two or three very small islands, and it is therefore susceptible to stochastic events and human impacts.

Previously published Red List assessments:
2010 Vulnerable (VU)
2008 Vulnerable (VU)
2006 Vulnerable (VU)
2004 Vulnerable (VU)
2000 Vulnerable (VU)
1996 Vulnerable (VU)
1994 Vulnerable (VU)
1988 Lower Risk/least concern (LR/lc)

Geographic Range [top]

Range Description: Pterodroma cervicalis breeds on Macauley Island in the Kermadec Islands, New Zealand (c.50,000 pairs in 1988, possibly increasing), with a second small colony recently established on Phillip Island, off Norfolk Island (to Australia) with nests increasing from six in 1994 to 20 in 2005 (Priddel et al. 2010). It bred on Raoul Island, also in the Kermadec Islands, early in the 20th century (Taylor 2000). The rare subspecies occulta breeds in small numbers on Vanua Lava, Vanuatu (Totterman 2009). It migrates to the tropical and sub-tropical north and southwest Pacific Ocean (Heather and Robertson 1997, J. Hobbs in litt. 2009), with a recent sighting off Gau Island, Fiji (Pym in litt. 2008). In February 2010, the rare sub-species P. occulta was photographed, 60 miles from the site of the original specimens, and only the second documented sighting since 1927; a total of 21 individuals were sighted over a three-day period, nine seen rafting before dusk (P. Harrison in litt. 2010).

Countries occurrence:
American Samoa (American Samoa); Australia; Cook Islands; Fiji; French Polynesia; Guam; Japan; Mexico; Micronesia, Federated States of ; New Caledonia; New Zealand; Niue; Norfolk Island; Northern Mariana Islands; United States; United States Minor Outlying Islands; Vanuatu; Wallis and Futuna
Present - origin uncertain:
French Southern Territories; Kiribati; Marshall Islands; Nauru; Papua New Guinea; Samoa; Solomon Islands; Tokelau; Tonga; Tuvalu
Estimated area of occupancy (AOO) - km2: 1
Continuing decline in area of occupancy (AOO): Unknown
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 67200000
Continuing decline in extent of occurrence (EOO): Unknown
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 3
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Upper elevation limit (metres): 50
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The total population has been estimated at c.100,000 mature individuals, roughly equivalent to 150,000 total individuals.

Trend Justification:  The population is thought to be increasing (Brooke 2004).

Current Population Trend: Increasing
Additional data:
Number of mature individuals: 100000 Continuing decline of mature individuals: Unknown
Extreme fluctuations: No Population severely fragmented: No
No. of subpopulations: 1 Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: Yes
No. of individuals in largest subpopulation: 100

Habitat and Ecology [top]

Habitat and Ecology: On Macauley Island it nests in burrows, generally on high, gently sloping areas with sedges and grass. On Raoul, it nested below 300 m on high-altitude ridges (Marchant and Higgins 1990). On Phillip Island, it is a summer breeder, birds coming ashore as early as 11 November, but laying in January (Priddel et al. 2010), differing from the Macauley population by nesting among boulders and in crevices in rocky habitat with sparse understorey, below a canopy of mature white oaks that provide concealment from avian predators (Priddel et al. 2010). It has also been known to nest in artificial cavities. On Phillip, the only known nests are at the top of Long Valley, but other areas have potential nest sites (Priddel et al. 2010). It feeds mainly on squid (Heather and Robertson 1997). Little is known of the breeding biology.

Systems: Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat: Unknown
Generation Length (years): 15.6
Movement patterns: Full Migrant
Congregatory: Congregatory (and dispersive)

Threats [top]

Major Threat(s): The population on Raoul was probably destroyed by feral cats and brown rat Rattus norvegicus (Taylor 2000). The Pacific rat R. exulans was formerly present on Macauley (eradicated in 2006), but does not apparently attack eggs or chicks (Marchant and Higgins 1990). Feral goats were present on both Raoul and Macauley and trampled burrows. Rabbits were formerly present on Phillip, and extensive grazing and burrowing caused large-scale erosion (Taylor 2000). It remains vulnerable to the introduction of further mammalian predators, and also to fire and disturbance by visitors (Marchant and Higgins 1990). The most recent visits to Macauley Island indicate that a dense successional stage of fern-dominated vegetation appears to be displacing the species from some colonies; however, population level impacts are not currently known (G. Taylor in litt. 2012). The species is potentially threatened by climate change because it has a geographically bounded distribution: it is restricted to an island or islands with a maximum altitude of 238 m (BirdLife International unpublished data).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Goats were removed from Raoul and Macauley in 1984 and 1970, respectively. The eradication of rabbits from Phillip in 1985 may have resulted in the species colonising the island in the following years. Pacific rates were eradicated from Macauley in 2006 and cats and rats were eradicated from Raoul Island between 2002 and 2006 (G. Taylor in litt. 2012). Since 2009, automated sound attraction units have been installed on Raoul Island in an attempt to lure the species, although there is no evidence so far that this has worked (G. Taylor in litt. 2012). A study area on Macauley was established in 1988 (G. Taylor in litt. 1999). The Kermadec Islands are nature reserves with access by permit only. Extensive searches were conducted for incubating birds of this species in the upper reaches of Long Valley, the main water catchment of Phillip Island (N. Carlile in litt. 2012).

Conservation Actions Proposed
Map populations on Macauley Island and complete a census. Monitor Macauley every five years to ensure that no establishment of predators has occurred. Monitor the recovery of vegetation on Macauley and any negative effects on the species. Recapture birds in study area to determine data on survival and longevity every five years. Re-establish colony on Raoul (Taylor 2000). Survey Vanua Lava and assess threats.

Citation: BirdLife International. 2012. Pterodroma cervicalis. The IUCN Red List of Threatened Species 2012: e.T22697957A40185605. . Downloaded on 27 November 2015.
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