 The Bonin petrel is currently thought to be closely related to the mottled petrel and white-necked petrel in the subgenus "Proaestrelata", based on a review of the whole genus "Pterodroma" looking at morphology, calls, breeding biology, diet and parasitic lice.Despite the species having two remote and separate breeding localities the species is monotypic and no subspecies are recognised.995,000 individuals, about 99% of the total population, breed on the Northwestern Hawaiian Islands, while 5,000 individuals (1% of the population) breed off the coast of Japan on the Ogasawara and Volcano Islands.