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)
.
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). 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). 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 Chicken Islands is probably less than 500 pairs. Other populations are tiny. The total breeding population is estimated at 5,000-10,000 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 December 2015 (J. Stewart
pers.comm.). A banded adult found in May 2005 offshore Lelehudi Village, Milne Bay Province, Papua New Guinea, may indicate that 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).
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 breeding sites managed by the Department of Conservation of New Zealand 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).
