The prions are small and typically eat just zooplankton;[2] however as a member of the Procellariiformes, they share certain identifying features.

[3] Finally, they also have a salt gland that is situated above the nasal passage and helps desalinate their bodies, due to the high amount of ocean water that they imbibe.

Also from the Greek language, prion comes from the word priōn meaning "a saw", which is in reference to its serrated edges of its bill.

Salvin's prion is a small 29 cm (11 in) petrel with grey and white plumage,[citation needed] and a blue bill.

[citation needed] This small prion breeds colonially on a number of subantarctic islands in the southern Indian Ocean.

The colonies of medium-billed prions are attended nocturnally in order to avoid predation by skuas.

Although numbers have declined on some islands where rats and feral cats have been introduced,[citation needed] the world population is estimated at around 12 million birds.