Puffinus Puffinus Puffinus is a genus of seabirds in the order Procellariiformes. It comprises about 20 small to medium-sized shearwaters. Two other shearwater genera are named: "Calonectris", which comprises three or four large shearwaters, and "Ardenna" with another seven species (formerly often included within "Puffinus"). "Puffinus" is a New Latin loanword based on the English "puffin". The original Latin term for shearwaters was usually the catchall name for sea-birds, "mergus". "Puffin" and its variants, such as poffin, pophyn and puffing, referred to the cured carcass of the fat nestling of the shearwater, a former delicacy. The original usage dates from at
Christmas shearwater subalaris"). The Christmas shearwater is a slender-bodied shearwater, about 36 cm long, with a wingspan of around 75 cm, and weighs around 350 g. It has dark plumage all over, generally blackish-grey with a rusty-brown tinge, slightly paler on the underside of the bird, and with some small edging of white under the chin and pale fringes to the upperwing coverts. It has brown-grey feet and a dark bill and eyes. Both sexes are alike, as are the young after fledging. Nestlings are covered in dark grey down feathers. The species closely resembles the sooty ("Puffinus griseus") and short-tailed shearwaters