Yelkouan shearwater Menorca. A study of these birds recommended that a combination of morphological characteristics and DNA sequence data should be required at least for scientific purposes to assign individual birds to either species. It was formerly considered a subspecies of the Manx shearwater (see there for more on the "Puffinus puffinus" superspecies). After the first split, it was the nominate subspecies of the so-called "Mediterranean shearwater" for nearly ten more years; it is considered a monotypic species now, as the Balearic form "mauretanicus" has been separated as the Balearic shearwater. The yelkouan shearwater appears to belong to a group of Mediterranean
Shearwater Shearwater Shearwaters are medium-sized long-winged seabirds. There are more than 30 species of shearwaters, a few larger ones in the genus "Calonectris" and many smaller species in the genus "Puffinus". The "Procellaria" petrels and "Bulweria" were believed to belong to this group, but are only distantly related based on more recent studies, while the "Pseudobulweria" and "Lugensa" "petrels" are more closely related. The genus "Puffinus" can be divided into a group of small species close to "Calonectris" and a few larger ones more distantly related to both. These birds are most common in temperate and cold waters. They are pelagic