Audubon's shearwater ill-resolved clade also including such species as the little shearwater, the Manx shearwater ("P. puffinus") or the black-vented shearwater ("P. opisthomelas"). The little-known Heinroth's shearwater ("P. heinrothi") is sometimes considered a subspecies of either Audubon's or the little shearwater. Though it is likely to be another member of that close-knit group, its actual relationships remain uncertain due to lack of specimens. Audubon's shearwater itself has around 10 subspecies. Several have at one time or another been suggested to constitute separate species. For example, the Galápagos Islands population has turned out to be a very distinct species, the Galápagos shearwater ("P.
Chagos Marine Protected Area Chagos are considered to be of international importance. The archipelago harbours eighteen different species of breeding birds and ten of its islands have been designated as Important Bird Areas (IBAs) by Birdlife International, making the region the most diverse breeding seabird community in this tropical region, though the presence of human-introduced rats on several of the other islands severely hinder seabird nesting on these. Five species are considered to be breeding in internationally significant numbers: the sooty tern ("Sterna fuscata"); the brown and lesser noddy ("Anous stolidus" and "Anous tenuirostris"); the red-footed booby ("Sula sula") and the wedge-tailed shearwater ("Puffinus