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.
Giannutri in the northern part which become "garrigue" in the southern. Plants as "arbutus", "Myrtus", "pistacia lentiscus", mock privet, Mediterranean buckthorn, "juniperus phoenicea" and "limonium sommierianum" knew only on Isola del Giglio and Montecristo, grow up on the island. The mild climate has favoured the growth of plants such as "euphorbia", palm trees and wild orchids. The marine flora is abundant in sponges, madreporaria, black coral and red coral. The island, as all that of the Tuscan Archipelago, is a place where the bird migration take a stop along their seasonal movement from North to South. The Audouin's gull, Puffinus yelkouan,