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
Calonectris Calonectris Calonectris is a genus of seabirds. The genus name comes from Ancient Greek "kalos", "good" and "nectris", "swimmer". The genus comprises three large shearwaters. There are two other shearwater genera. "Puffinus", which comprises about twenty small to medium-sized shearwaters, and "Procellaria "with another four large species. The latter are usually named as "petrels", although they are thought to be more closely related to the shearwaters than to the other petrels. The taxonomy of this group is the cause of some debate, and it is only recently that the Cape Verde shearwater has been split from Cory's shearwater. The species