are seabirds in the bird
order Procellariiformes. They occur in three families within that group, which also includes the Albatross
family, Diomedeidae. Having a fossil
record that extends back at least 60 million years, it is among the older bird groupings, other than the ratites
, with distant ties to penguins
and loons. However, recent research shows that the Galliformes
and relatives), and Anseriformes
) are older.
All the members of the order are exclusively pelagic in distribution -- returning to land only to breed.
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 prionss, 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
- Bulwer's Petrel, Bulweria bulwerii
- Jouanin's Petrel, Bulweria fallax
- 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.