Belongs within: Lari.
The Stercorariidae, skuas, are gull-like pelagic birds with a bipolar distribution. They are distinguished from gulls by the presence of a distinctive sheath at the base of their hooked bills. Those species breeding in the Northern Hemisphere, also known as jaegers, have central tail feathers extending well beyond the remainder of the tail. Authors have differed on whether all living skuas should be included in a single genus Stercorarius or whether this genus should be restricted with the smaller jaegers, with the larger skuas of the Southern Hemisphere treated as a distinct genus Catharacta. The jaegers also show variation in plumage patterns between dark and pale morphs, with dark morphs being entirely dark brown whereas pale morphs have yellow and white areas on the sides of the head and underparts.
<==Stercorariidae [Catharactinae, Lestridinae, Stercorariinae]
| i. s.: ‘Larus’ desnoyersii Milne-Edwards 1863M02
`--Stercorarius Brisson 1760 (see below for synonymy)CC10
| i. s.: S. cepphus (Brünn. 1764) (see below for synonymy)S05
| S. lonnbergi (Mathews 1912)CC10, JT12, CC10 (see below for synonymy)
| S. shufeldtiFP64
|--S. longicaudus Vieillot 1819BKB15, CC10 [=Lestris longicaudusCC10]
| |--S. l. longicaudusCC10
| `--S. l. pallescens Løppenthin 1932CC10
`--+--*S. parasiticus (Linnaeus 1758)CC10, BKB15, CC10 (see below for synonymy)
`--+--S. skua (Brünnich 1764)BKB15, WH02 (see below for synonymy)
`--+--S. pomarinus (Temminck 1815)BKB15, CC10 (see below for synonymy)
`--+--S. maccormicki Saunders 1893CC10 (see below for synonymy)
`--+--S. antarcticus (Lesson 1831)BKB15, CC10 (see below for synonymy)
| |--C. a. antarcticaCC10
| `--C. a. hamiltoni Hagen 1952CC10
`--S. chilensisAP21 [=Catharacta chilensisJT12, Megalestris chilensisHD09]
Stercorarius Brisson 1760 [=Lestris Illiger 1811; incl. Catharacta Brünnich 1764, Coprotheres Reichenbach 1850, Megalestris Bonaparte 1856]CC10
Stercorarius antarcticus (Lesson 1831)BKB15, CC10 [=Lestris antarcticusCC10, Catharacta antarcticaCC10, Megalestris antarcticaCC10]
Stercorarius cepphus (Brünn. 1764) [=Catharacta cepphus, Lestris cepphus; incl. Stercorarius buffoni Kumlien 1879, L. buffoni, S. richardsoni Seebohm 1888]S05
Stercorarius lonnbergi (Mathews 1912)CC10, JT12, CC10 [=Catharacta antarctica lonnbergiCC10, C. skua lonnbergiCC10, Stercorarius skua lonnbergiCC10; incl. S. antarcticus madagascariensis Bonaparte 1856 (nom. rej.)CC10]
Stercorarius maccormicki Saunders 1893CC10 [=Catharacta skua maccormickiCC10, JT12, Megalestris maccormickiCC10, Stercorarius skua maccormickiCC10; incl. Catharacta maccormicki wilsoni Mathews 1913CC10]
*Stercorarius parasiticus (Linnaeus 1758)CC10, BKB15, CC10 [=Larus parasiticusCC10, Catharacta parasiticaCC10, *Lestris parasiticusCC10; incl. Larus crepidatus Banks 1773CC10, Lestris crepidataS05, Stercorarius crepidatusCC10, S. parasiticus visitori Mathews 1915CC10]
Stercorarius pomarinus (Temminck 1815)BKB15, CC10 [=Lestris pomarinusCC10, Catharacta pomarinaCC10, *Coprotheres pomarinusCC10, Larus pomarinusS05, Lestris pomatorhinusS05, Stercorarius pomatorhinusS05; incl. Coprotheres pomarinus nutcheri Mathews 1917CC10, S. pomarinus philippi Mourer-Chauviré 1975M02]
Stercorarius skua (Brünnich 1764)BKB15, WH02 [=*Catharacta skuaCC10, Buphagus skuaS05, Megalestris skuaS05; incl. Larus catarractes Linnaeus 1766CC10, Lestris catarractesCC10, *Megalestris catarractesCC10, Stercorarius catarractesCC10, Cataracta fuscaF17]
*Type species of generic name indicated
References
[AP21] Arlott, N., & B. van Perlo. 2021. Collins Birds of the World. William Collins.
[BKB15] Burleigh, J. G., R. T. Kimball & E. L. Braun. 2015. Building the avian tree of life using a large-scale, sparse supermatrix. Molecular Phylogenetics and Evolution 84: 53–63.
[CC10] Checklist Committee (OSNZ). 2010. Checklist of the Birds of New Zealand, Norfolk and Macquarie Islands, and the Ross Dependency, Antarctica 4th ed. Ornithological Society of New Zealand and Te Papa Press: Wellington.
[FP64] Fisher, J., & R. T. Peterson. 1964. The World of Birds: A comprehensive guide to general ornithology. Macdonald: London.
[F17] Forster, T. 1817. A synoptical catalogue of British birds; intended to identify the species mentioned by different names in several catalogues already extant. Forming a book of reference to observations on British ornithology. Nichols, Son, and Bentley: London.
[HD09] Hutton, F. W., & J. Drummond. 1909. The Animals of New Zealand: An account of the Dominion’s air-breathing vertebrates 3rd ed. Whitcombe and Tombs Limited.
[JT12] Jetz, W., G. H. Thomas, J. B. Joy, K. Hartmann & A. Ø. Mooers. 2012. The global diversity of birds in space and time. Nature 491: 444–448.
[M02] Mlíkovský, J. 2002. Cenozoic Birds of the World. Part 1: Europe. Ninox Press: Praha.
[S05] Schalow, H. 1905. Die Vögel der Arktis. In: Römer, F., & F. Schaudinn (eds) Fauna Arctica. Eine Zusammenstellun der arktischen Tierformen, mit besonder Berücksichtigung des Spitzbergen-Gebietes auf Grund der Ergebnisse der Deutschen Expedition in das Nördliche Eismeer im Jahre 1898 vol. 4 pp. 79–288. Gustav Fischer: Jena.
[WH02] Worthy, T. H., & R. N. Holdaway. 2002. The Lost World of the Moa: Prehistoric life of New Zealand. Indiana University Press: Bloomington (Indiana).