Petrel

The family Procellariidae is the main radiation of medium-sized 'true petrels', characterised by united nostrils with medium septum, and a long outer functional primary. It is dominant in the Southern Oceans, but not so in the Northern Hemisphere.

It includes a number of petrel groups

• The fulmars: 7 species: surface predators and filter feeders, breed in high latitudes but migrate along cool currents to he north. All but Fulmarus essentially confined to the south, Fulmarus apparently colonised the N hemisphere during the Tertiary.
  • The huge giant petrels[?], genus Macronectes, which are convergent with the albatrosses.
  • The true fulmars, genus Fulmaris
  • Antarctic Petrel[?], Thalassoica antarctica
  • Cape Petrel[?], Daption capense
  • Snowy Petrel[?], Pagodroma nivea.
• The prions, genus Pachyptila. A specialised group of six very numerous species, all southern. They have a small, fulmar-like form and filter-feed on zooplankton.
• The gadfly petrels. These are large and agile short-billed petrels in the genus Pterodroma.
• Shearwaters in the genera Calonectris, Puffinus and Procellaria. The three species in the last genus are named as petrels
• Petrels of indeterminate relationships
  • the four Bulweria species
  • Blue Petrel[?], Halobaena caerula
  • Kerguelen Petrel[?] Lugensa brevirostris
  • Tahiti Petrel[?] Pseudobulweria rostrata.

The family Hydrobatidae is the storm-petrels, small pelagic petrels with a fluttering flight which often follow ships.

The family Pelacanoididae is the four species of diving petrels, genus Pelacanoides. These are auk-like small petrels of the southern oceans.

The taxonomy of the petrels is complex, and several genera are intermediate.