Black-vented shearwater Black-vented shearwater The black-vented shearwater ("Puffinus opisthomelas") is a species of seabird. The bird is 30–38 cm in size, with a 76–89 cm wingspan. Formerly considered a subspecies of the Manx shearwater, its actual relationships are unresolved. This species is pelagic, occurring in the Pacific Ocean and the Gulf of California. It comes closer to land than most other shearwaters, so it sometimes can be seen from shore. It predominantly nests on offshore islands off north and western Baja California, namely Isla de Guadalupe, Islas San Benito and Isla Natividad. It is fairly common off the United States coast of
Procellariidae with "Pseudobulweria" being phylogenetically closer to the "Puffinus" shearwaters than the "Pterodroma" gadfly petrels, and "Aphrodroma" (the Kerguelen petrel) possibly being closely related to the shearwaters or the fulmars. The prions, according to Nunn and Stanley, were among the larger shearwater group. The "Calonectris" shearwaters were placed close to the two "Puffinus" clades (closer to the Puffinus, or small, clade) and both were distant to the "Procellaria" shearwaters. The relationships between the genera and within the genera are still the subject of debate, with researchers lumping and splitting the species and genera within the family and arguing about the position