Pterodroma pycrofti 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Procellariiformes Procellariidae

Scientific Name: Pterodroma pycrofti Falla, 1933
Common Name(s):
English Pycroft's Petrel
Spanish Petrel de Pycroft
Taxonomic Source(s): Turbott, E.G. 1990. Checklist of the Birds of New Zealand. Ornithological Society of New Zealand, Wellington.
Identification information: 26 cm. Small, grey-and-white petrel. White forehead merging into grey crown. Grey neck, back, uppertail-coverts, tail. Darker patch around eye. Darker grey wings showing "M" in flight. White underparts with indistinct grey half-collar. White underwing with dark tip, dark line along leading edge, extending indistinctly from carpal joint towards body. Similar spp. Separated from most other small gadfly petrels by whiter underwing. Stejneger's Petrel P. longirostris has more extensive, dark eye-patch. Cook's Petrel P. cookii generally appears lighter with lighter crown and eye patch. Pycroft's Petrel P. pycrofti may not be separable from de Fillipi's Petrel P. defilippiana, but ranges may not overlap.

Assessment Information [top]

Red List Category & Criteria: Vulnerable D2 ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Miskelly, C., Pierce, R., Rayner, M. & Taylor, G.A.
Facilitator/Compiler(s): Anderson, O., Benstead, P., Calvert, R., McClellan, R., Moreno, R. & Taylor, J.
This species is classified as Vulnerable because it has a very small range when breeding, being restricted to five tiny island groups, with the majority of the population on one island. It has a small population, but numbers are apparently increasing at one site and likely to be stable or possibly increasing elsewhere.

Previously published Red List assessments:

Geographic Range [top]

Range Description:Pterodroma pycrofti breeds under forest on 12 offshore islands along the east coast of New Zealand, in the Poor Knights Islands, the Hen and Chicken Islands, the Mercury Islands, and Ririwha (= Stephenson). Chick translocations to Cuvier Island in 2001-2003 have resulted in a small breeding population (numbering 14 pairs in 2012 and 20 pairs in 2015) (G. Taylor and Rob Chappell in litt. 2016). Subfossils indicate that the species once bred on Norfolk and Lord Howe Islands (to Australia) (Heather and Robertson 1997). Red Mercury Island (c.80% of total) supported 1,000-2,000 pairs in 1989-1991, and 2,000-3,000 in 1998. Surveys in 2010 indicate that this population has expanded to 5,000-10,000 pairs and is the dominant seabird on the island (G. Taylor in litt. 2012). The population at the Hen and Chickens is probably less than 500 pairs. Other populations are tiny. The total breeding population is estimated at c.10,000 pairs, with a total population of 30,000-40,000 birds (G. Taylor in litt. 2012). A translocation of Pycroft’s petrel chicks to Motuora Island started in March 2013 and two returned birds were seen ashore in Dec 2015 (J. Stewart pers.comm.) . A banded adult found 5 May 2005 offshore Lelehudi Village, Milne Bay Province, Papua New Guinea, may indicate some birds spend the non-breeding season in the Papua New Guinea region. The timing of the recovery does not rule out the possibility of a passing migrant (Pierce 2009). Studies utilising geolocators have shown that, when not breeding, birds disperse to the central and eastern tropical Pacific (G. Taylor in litt. 2012; Rayner et al. 2016).

Countries occurrence:
New Zealand; United States; United States Minor Outlying Islands; Wallis and Futuna
Present - origin uncertain:
Fiji; Kiribati; Marshall Islands; Micronesia, Federated States of ; Nauru; New Caledonia; Solomon Islands; Tonga; Tuvalu; Vanuatu
Additional data:
Estimated area of occupancy (AOO) - km2:31Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:98900000
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:5Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:No
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The total breeding population is estimated at 5,000-10,000 pairs, equating to 12,000-22,000 mature individuals, within a total population of 30,000-40,000 individuals (G. Taylor in litt. 2012). There has been no population monitoring at any breeding colony (except the two translocation sites) since 2012 (G.Taylor in litt. 2016).

Trend Justification:  The population is increasing in response to rat eradication.

Current Population Trend:Increasing
Additional data:
Number of mature individuals:12000-22000Continuing decline of mature individuals:Unknown
Extreme fluctuations:NoPopulation severely fragmented:No
No. of subpopulations:5Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

Habitat and Ecology [top]

Habitat and Ecology:It digs burrows on flat to steep coastal slopes below 150 m, often interspersed with other petrel colonies (Marchant and Higgins 1990, Heather and Robertson 1997). Adults return in Oct to clean out burrows, with egg-laying occurring in Nov-Dec, and young departing in Mar-Apr (Pierce 2009). Its diet is not well known, although it is known to take squid (Heather and Robertson 1997) and crustaceans (G. Taylor in litt. 2012).

Systems:Terrestrial; Marine
Continuing decline in area, extent and/or quality of habitat:Unknown
Generation Length (years):11
Movement patterns:Full Migrant
Congregatory:Congregatory (and dispersive)

Threats [top]

Major Threat(s): Pacific rat Rattus exulans has a significant impact on breeding success, taking eggs and chicks (Heather and Robertson 1997, Pierce 1998). The threatened endemic reptile tuatara Sphenodon punctatus is also a natural predator of eggs and chicks, but appears to have no major effect on populations (Marchant and Higgins 1990, Pierce 1998). Little Shearwaters Puffinus assimilis compete for nesting sites, and generally dominate when their populations are large (R. Pierce in litt. 1999). Although they presently have little effect on breeding success (Pierce 1998), competition may become problematic in the future as populations increase in response to a release from predator pressure (R. Pierce in litt. 1999, Taylor 2000)

Conservation Actions [top]

Conservation Actions:

Conservation Actions Underway

Between 1987 and 1997, eradications of R. exulans were completed on Korapuki, Double, Stanley, Red Mercury, Lady Alice, Whatupuke and Coppermine Islands (Taylor 2000). As a result, breeding success has improved (as has that of P. assimilis [R. Pierce in litt. 1999]). Study populations have been established on Red Mercury and Stanley Islands. Populations on the Chicken Islands group  were studied in the 1990s (Taylor 2000). Chick translocations to Cuvier Island in 2001-2003 have resulted in a small breeding population (G. Taylor in litt. 2012). Hen Island (500 ha) was cleared of R. exulans in 2011 (G. Taylor in litt. 2016). Pycroft’s Petrels were still present on Aorangi Island in 2013 but numbers seem very low (G.Taylor pers. comm. 2016). All NZ Department of Conservation managed breeding sites get a biosecurity audit (using trained pest detection dogs) every 1-2 years (G. Taylor pers. comm.).

Conservation Actions Proposed

Survey Ririwha and Aorangi Islands to confirm breeding status and population size, and survey Fanal, Three Kings and Ohinau Islands for new colonies. Eradicate R. exulans from Ririwha Island if owners consent. Check all islands at least every five years to ensure that introduced predators have not established (Taylor 2000). 

Citation: BirdLife International. 2016. Pterodroma pycrofti. The IUCN Red List of Threatened Species 2016: e.T22697984A93651498. . Downloaded on 20 August 2018.
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