Manx shearwater Morten Thrane Brünnich as "Procellaria puffinus" in 1764. The current scientific name "Puffinus" derives from "puffin" and its variants, such as poffin, pophyn and puffing, which referred to the cured carcass of the fat nestling of the shearwater, a former delicacy. The original usage dates from at least 1337, but from as early as 1678 the term gradually came to be used for another seabird, the Atlantic puffin. The current English name was first recorded in 1835 and refers to the former nesting of this species on the Isle of Man. The Manx shearwater is with a wingspan and weighs
Audubon's shearwater homogeneous north-western Indian Ocean range, but not in the ecologically more diverse and by far larger Pacific range of "dichrous". These unresolved problems notwithstanding, this clade – possibly including the preceding one – has been proposed to constitute a separate species, the tropical shearwater or Baillon's shearwater, "Puffinus bailloni". These taxa could not be included in the most recent studies due to lack of material. The case of "gunax" seems fairly straightforward – as certainly as this can possibly be said in the absence of new data, it belongs to the "bailloni" clade either as a distinct subspecies, or, more