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
Audubon's shearwater likely, as yet another synonym of "dichrous". The case of the more distinct "bannermani", the range of which is parapatric to that of the Pacific "dichrous", is more complicated. It has for some time been proposed as a distinct species, Bannerman's shearwater ("P. bannermani"). In the absence of more recent data to investigate this claim, its status continues to be altogether unresolved, though the case for it being at least a distinct subspecies in the "bailloni" clade seems good. Audubon's shearwater The Audubon's shearwater ("Puffinus lherminieri") is a common tropical seabird in the petrel family. Sometimes known as the dusky-backed