Cytochrome b data in Penhallurick and Wink (2004) were unable to establish the closest relatives of the Pachyptila-Halobaena group, and left it as incertae sedis.
Broad-billed, Salvin's, and Antarctic Prions are often considered separate species due to differences in bill structure, coloration, and biology (Harper 1980; Sibley and Monroe 1990; Bretagnolle et al 1990), but some authors (Harrison 1983, Cox 1980) believe Salvin's to be intermediate between the other 2, with both of which it interbreeds, and also that Broad-billed and Slender-billed are conspecific due to interbreeding where their ranges overlap. Cox (1980) noted interbreeding between Fairy and Fulmar Prions, suggesting conspecificity (Harrison 1983). Penhallurick and Wink (2004) concluded from cytochrome b data that Fairy and Fulmar Prions are best considered conspecific and separate at the species level from the remaining 4 taxa, which they considered conspecific also, thus leaving only 2 species within Pachyptila. Thus various treatments indicate as few as 2 (Penhallurick and Wink 2004) or as many as 6 species (Harper 1980; HANZAB). Herein 6 species are listed, based in part on conclusions reached by Tennyson and Bartle (2005) regarding status of Fulmar Prions, and OSNZ (2010).
Halobaena caerulea Blue Petrel
Pterodroma axillaris Chatham Island Petrel
Breeds Chatham Is (Rangatira I 100 prs, total 500-1000 inds; 55 chicks per year transferred to predator-proof area Pitt I, first returnees expected 2004-2005, Aikman and Miskelly 2004; transferred to Sweetwater Conservation Covenant 2008-2011 (Miskelly and Powlesland 2013). Eggs Dec-Jan. At sea in vicinity Dec- May, possibly mostly to south: 11 were observed off Bounty Is Jan 2000 (Shirihai 2002). Absent breeding location Jun-Nov, apparently to eastern tropical Pacific, as one photographed 820 miles w of Peru 11 Oct 2006 (Force et al 2009).
P. nigripennis Black-winged Petrel
Breeds New Caledonia (Walpole, Matthew, Barre and Dutson 2000; 1000 prs Southern Lagoon, Benoit and Bretagnolle 2002); Lord Howe I 1000 prs (Baker et al 2002), Norfolk I (Phillip I "a few hundred" prs, Norfolk I "a few", Baker et al 2002), NZ (NI: Three Kings, Motuopao, Motupia, Simmonds, Motukokako, East, Portland, OSNZ 2010; Mokohinau Is: Burgess, Ismar et al 2012), Kermadec Is (2.5 million prs Macauley, 300,000 prs Curtis, 10,000+ prs Cheeseman, 1000+ prs Herald, 200 prs L'Esperance, extirp Raoul, Veitch et al 2004), Chatham Is (Rangatira, Mangere, poss Pitt, Forty-fours, Star Keys, Jenkins and Cheshire 1982), Tonga, Cook Is (Rarotonga), Austral Is (Rapa, Bass Rocks). Eggs Kermadec Is Dec-Jan, Phillip I Dec-Jan, Lord Howe I Jan-Feb (McAllan et al 2004). At sea Oct-May vicinity of breeding locations (Jenkins and Cheshire 1982; but 2 seen se Norfolk I 21 Jul, Barnard), Apr-Dec to 30N in c Pacific, incl near Japan, Mariana Is (Pagan, Asuncion, Reichel and Glass 1991), Hawaiian Is (SE Is only, numerous year-round but most May-Dec with peak Oct-Nov, Pyle and Pyle 2009), Kiribati, Marshall Is, Fiji (incl 3 in May, Pym and Hadoram; "expected at least in s. Fijian waters Nov-Jun" Jenkins and Cheshire 1982), Tonga, Cook Is, Society Is, Marquesas Is, Easter I (Jaramillo), near Baja California and s to Peru.
P. occulta Vanuatu Petrel
Breeds Vanuatu (?Banks Is- northern Vanuatu, Imber and Tennyson 2001; Vanua Lava, Totterman 2009, Mt. Suretamatai considered "the only known breeding site", Totterman, 2012; 6 specimens collected Mere Lava Jan 1927; Bregulla 1992). At sea in vicinity (Shirihai and Bretagnolle 2010) and to Australia (Imber and Tennyson 2001); winter possibly to north Pacific (Imber and Tennyson 2001). Breeds Jan-May (Totterman 2009).
P. cervicalis White-necked (White-naped) Petrel
Breeds Kermadec Is (Macauley I 50,000 prs, extirp Raoul I, Veitch et al 2004), Norfolk I (Phillip I, 5 prs Baker et al 2002; increasing- 10-100 prs 2006, Priddel et al 2010). At sea Oct-Jun vicinity of breeding locations sw Pacific poss n as far as s Tonga, and s to NZ (Jan-Apr NI, mostly East Cape area); May-Oct n to 30N in nw Pacific (Fiji and Tonga mostly May-Jul, 6 recs Japan Jul-Sep, well offshore Mariana Is Reichel and Glass 1991, but unrecorded Palau, Caroline Is, Pyle and Engbring 1985), e to 110E incl Hawaiian Is, also Kiribati, Fiji, Tonga, Samoa, Cook Is (Holyoak 1980). Cas Dec New Caledonia (Barre and Dutson 2000; poss P. occulta?, Dutson 2011), Jan-Mar Lord Howe I (McAllan et al 2004). Hypo Marshall Is (Pyle and Engbring 1985). Eggs Kermadec Is Dec-Jan (Veitch et al 2004).
P. externa Juan Fernandez Petrel
Breeds Juan Fernandez Is (Mas Afuera I 1,000,000 prs). Eggs Dec-Jan. At sea May-Nov e Pacific, from 90W to 170W, incl Hawaiian Is May-Sep (Pyle and Pyle 2009) and n Jul-Sep to 20N incl Clipperton I and Revillagigedo Is. Cas NZ (Oct 1971, Jun 2005, OSNZ 2010); present at Chatham Is (Rangatira I, Mangere I) Oct-Mar 1984-1999, including one in burrow Rangatira I Mar 1997 (Miskelly et al 2006). Acc Japan (Tokyo) Sep (Brazil 1991).
P. inexpectata Mottled Petrel
Breeds Snares Is 30,000-40,000 prs (Miskelly et al 2001),NZ (Codfish I 300,000-400,000 prs- Miskelly et al 2001; Stewart I: Big South Cape I 10,000 prs; SI: island in L Hauroko, Shag I, Front I; Solander Is). Eggs Dec. At sea c Pacific Mar-Nov (absent Snares Is Jun-Oct; non- and failed breeders leave Feb-Mar), Jun-Sep n to Alaska and Aleutians; Feb, Apr, Nov-Dec off California (McGrath and Feenstra 2005); pass through tropics Mar-May and late Sep-Nov (first seen Johnston Atoll area late Sep, good numbers early Oct, Force and Webb), incl May (south of New Caledonia) and Oct (110 birds between Grande Terre and Loyalty Is) New Caledonia (Barre and Dutson 2000), Lord Howe I Nov and Jan (McAllan et al 2004), Norfolk I May (R. Clarke), Hawaiian Is (almost all records Oct and Apr, Pyle and Pyle 2009), e Kiribati, Fiji-Tonga Mar-May and Oct (Jenkins 1986), but a few follow S. American coast s to Humboldt Current. Acc Oct-Nov Galapagos Is, Dec-Mar Macquarie I where may begin breeding, incl 25 on Jan 22, 2003 (R. Clarke, M. Carter).
P. hypoleuca Bonin Petrel
Breeds Ogasawara Is, Iwo Is, w Hawaiian Is (Kure e to French Frigate 1,300,000 inds, 400,000 prs, Pyle and Pyle 2009). Eggs Nov-Feb. At sea Oct-Apr nw and c Pacific (May-Aug n to 40N in Japan area), incl Mariana Is (Reichel and Glass 1991), Caroline Is (Dixon and Starrett 1952), Marshall Is (Pratt et al 1987), nothern Kiribati (Pratt et al 1987).
P. leucoptera Gould's Petrel