Procellariiformes, a group that includes species covering a wider range of body mass than any other order. In spite of this, the Procellariiformes are quite a uniform group in many aspects of their biology. As regards their flight, all are pelagic, coming ashore only to breed, and all depend for successful breeding on making foraging excursions to feeding areas at sea, both during incubation and when rearing their young. This order can at once be distinguished from all existing birds by the character of the nostrils, which terminate in tubes, parallel to the line of the beak, sometimes united, but generally double when viewed from in front. The size is varied ; the smallest forms are about the size of a starling, while the largest albatross, though not very bulky in body, has a spread of wing exceeding that of any other bird. The order is purely pelagic in habits and extends over the whole globe. It reaches, however, its maximum development in the south temperate and sub-Antarctic zones, and its members are relatively scarce in the equatorial tropics. One egg is laid-or at most two-generally in burrows, on islands, or sometimes on the summits of mountains near the sea, and the young are helpless until nearly full-grown. The Procellariiformes contains some of the most globally threatened species of birds in the world. Of 129 living species, fully 47% (60) species have been accorded a formal threatened status by BirdLife International.

The order of Procellariiformes consists of 4 families, 24 genera and 129 species. This order is commonly known as the "tubenoses". (named for the tubular-shaped nostrils), Albatrosses, Shearwaters, Petrels, Fulmars, Stormpetrels, Diving-petrels and Prions. Found in the oceans of the world, they are foremost pelagic (far out at sea, only come to land if necessary). The are highly adapted to living in salt arter. They are able to excrete salt from their glands in the nostrils, which allows them to drink sea water. The diet consists of fish, squid, other marine animals and sometimes carrion. Albatrosses are accomplished gliders; diving-petrels swim under water propelled by wings (like penguins) while the Petrels resort to plung-diving. Some species discharge a musky, stinky stomach oil from their nostrils and mouth when disturbed. Many of the species have an excellent sense of smell, which is used to find the nest at night. The nest is a hollow, crack, or crevice; sometimes lined; often on isolated islands. Tese birdd re commonly burrow-breedersith a slow birth rate. Usualy the clutch is one egg; incubation and care of nidicolous young is done by both parents. Thought to be related most closely to penguins, secondarily to loonsAn alarming two-thirds of the species is cureently listed on Red lists, threatened foremost by habitat destruction and disturbance and long fishing lines and nets.