The shearwaters form part of the family Procellariidae, a widespread group containing nearly 100 species of medium to large seabirds.

[2] Although it was considered a monotypic species, recently an endemic subspecies for the Canary Islands has been proposed P. puffinus canariensis.

[4][11] The current scientific name Puffinus derives from "puffin" and its variants, such as poffin, pophyn, and puffing,[12] which referred to the cured carcass of the fat nestling of the shearwater, a former delicacy.

The vocalisations largely consists of a raucous series of croons, howls, and screams, typically in groups of a few syllables, which become weaker and throatier.

The male has some clear ringing and shrieking tones absent from the harsher repertoire of the female, the difference being obvious when a pair duets.

The nocturnal vocalisations of Manx shearwater are notorious for their eerie character and the alarm they might arouse in uninitiated hearers.

Anecdotally: "the diabolical shrieks and cackles of this species have earned it, in various parts of the world and various languages, the local nickname 'Devil Bird'".

The shorter focal length of shearwater eyes give them a smaller, but brighter, image than is the case for pigeons.

Although the Manx shearwater has adaptations for night vision, the effect is small, and these birds likely also use smell and hearing to locate their nests.

The northeast of North America has recently been colonised from Newfoundland and Labrador to Massachusetts; although breeding was first recorded in 1973, populations remain small.

[24] For example, adult Manx shearwaters rearing their chick on the west coast of Ireland have been observed to travel all the way to the Mid-Atlantic Ridge to feed when the conditions are right.

Although shearwaters return to the breeding colonies from March onwards, the females often then leave again for 2–3 weeks before egg-laying in early May.

[32] The Manx shearwater feeds on small fish (herrings, sprats, and sand eels), crustaceans, cephalopods, and surface offal.

[33] Manx shearwaters engage in a behaviour termed "rafting", where birds sit, often in large groups of more than 10,000, on the water adjacent to their Skomer Island breeding colony before and after visiting their chicks.

These day-night cycles of rafting distributions are prominent for Manx shearwaters around Skomer Island and might provide a way of waiting for dusk that reduces predation risk.

[40] Manx shearwaters frequently carry feather lice (Mallophaga) most of which are either the feather-eaters in the groups Ischnocera, or Amblycera, which also consume blood.

[45] The European population of the Manx shearwater has been estimated at 350,000–390,000 breeding pairs or 1,050,000–1,700,000 individual birds, and makes up 95% of the world total numbers.

Although this species' population now appears to be declining, the decrease is not rapid or large enough to trigger conservation vulnerability criteria.

The moon cycle and strong onshore winds largely influence grounding events in west Scotland, and visibility conditions to a lesser extent.

[4] The large chicks of the Manx shearwater are very rich in oil from their fish diet and have been eaten since prehistoric times.

The breeding colonies at Trollaval on Rùm and Trøllanes and Trøllhøvdi in the Faroe Islands are believed to have acquired their troll associations from the night-time clamour.