# Petrel

Petrels are tube-nosed seabirds in the phylogenetic order Procellariiformes.

## Description

Petrels are a monophyletic group of marine seabirds, sharing a characteristic of a nostril arrangement that results in the name "tubenoses". Petrels encompass three of the four extant families within the Procellariiformes order, namely Procellariidae (fulmarine petrels, gadfly petrels, diving petrels, prions, and shearwaters), Hydrobatidae (northern storm petrels), and Oceanitidae (austral storm petrels). The remaining family in Procellariiformes is the albatross family, Diomedeidae.
Procellariiformes
Diomedeidae – albatrosses (21 species)
Oceanitidae – austral storm petrels (10 species)
Hydrobatidae – northern storm petrels (18 species)
Procellariidae – petrels and shearwaters (100 species) :
Phylogeny of the extant procellariforms based on a study by Richard Prum and colleagues published in 2015. Petrels (Procellariidae, Hydrobatidae, and Oceanitidae) form a monophyletic group according to this cladogram. :

## Etymology

The word petrel (first recorded in that spelling 1703) comes from earlier (ca. 1670) pitteral; the English explorer William Dampier wrote the bird was so called from its way of flying with its feet just skimming the surface of the water, recalling Saint Peter's walk on the sea of Galilee (Matthew xiv.28); if so, it likely was formed in English as a diminutive of Peter (< Old French: Peterelle (?) < Late Latin: Peterellus < Late Latin: Petrus < Ancient Greek: Πέτρος, romanized: Petros < Ancient Greek: πέτρα, romanized: petra = "stone").

## Known species

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 feather. It is dominant in the Southern Oceans, but not so in the Northern Hemisphere.
It includes a number of petrel groups, the relationships between which have finally been resolved to satisfaction.
* The fulmarine petrels: seven species of surface predators and filter feeders, breed in high latitudes but migrate along cool currents to the north. All but Fulmarus are essentially confined to the south, Fulmarus apparently colonised the Northern Hemisphere during the Early Miocene.
** The huge giant petrels, genus Macronectes, which are convergent with the albatrosses
** The true fulmars, genus Fulmarus
** Antarctic petrel Thalassoica antarctica
** Cape petrel Daption capense
** Snow petrel Pagodroma nivea
* The prions: A specialised group of a few very numerous species, all southern. They have a small, fulmar-like form and mostly filter-feed on zooplankton.
** Pachyptila, the prions proper
* The procellariine petrels, larger or mid-sized species feeding on fish and molluscs which are fairly close to the prions:
** Procellaria
** Bulweria
* Shearwaters: There are numerous species in several genera with a medium number of species.
** Calonectris
** Puffinus, which is two rather distinct groups of larger and smaller species
** Pseudobulweria
** Kerguelen petrel Lugensa brevirostris
* The gadfly petrels: These are a considerable number of agile short-billed petrels in the genus Pterodroma which include the endangered Bermuda petrel (or cahow) and a considerable number of forms rendered extinct by human activity.
* The diving petrels: These are the four species of auk-like small petrels of the southern oceans in the genus Pelacanoides.
The family Oceanitidae is the austral (or southern) storm petrels, and the family Hydrobatidae is the northern storm petrels. Collectively, they are known as the storm petrels, small pelagic petrels with a fluttering flight which often follow ships.

## In culture

Petrels are culturally significant, and well-known poems have been written about the bird. One such example is given here.
   Up and down! - up and down! From the base of the wave to the billow’s crown, And amidst the flashing and feathery foam The stormy petrel finds a home, -
   A home, if such a place may be For her who lives on the wide, wide sea.
   O’er the deep! - o’er the deep! Where the whale and the shark and the sword-fish sleep, - Outflying the blast and the driving rain, The petrel telleth her tale — in vain!