Pterodroma pycrofti


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Pterodroma pycrofti
Species Authority: Falla, 1933
Common Name/s:
English Pycroft's Petrel

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: Miskelly, C., Pierce, R., Rayner, M. & Taylor, G.
Facilitator/s: Anderson, O., Benstead, P., Calvert, R., McClellan, 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.

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) (G. Taylor in litt. 2012). 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). However, 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 (M. Rayner in litt. 2012, G. Taylor in litt. 2012).

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
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).
Population Trend: Increasing

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

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). 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 150 m (Birdlife International unpublished data).

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 have been studied since 1992 (Taylor 2000). Chick translocations to Cuvier Island in 2001-2003 has resulted in a small breeding population (G. Taylor in litt. 2012). Hen Island (500 ha) was cleared of R. exulans in 2011 (to be confirmed in 2013) (G. Taylor in litt. 2012).

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. Continue monitoring study burrows on Lady Alice, and monitor breeding density and burrow competition. 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 2012. Pterodroma pycrofti. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <>. Downloaded on 19 April 2014.
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