This small black-and-white shearwater is an endemic breeder to the Galapagos Islands, and a regular visitor to waters offshore north to Oaxaca, western Mexico, and Central America. It also has been reported a few times off the coasts of mainland Ecuador, Colombia and Peru, but those records are generally unsubstantiated by verifiable documentation. The Galapagos Shearwater only recently has been recognized as a full species; previously it was regarded as a distinctive, isolated subspecies of Audubon’s Shearwater Puffinus lherminieri.
Breeding on the islets off Santa Cruz, Española, Santa Cruz, Champion and Wolf Islands in the Galapagos archipelago, Galapagos Shearwaters are commonly encountered close to shore, where they may be seen foraging with boobies, terns and other species of shearwater. Within its breeding range, it is unlikely to be mistaken for any other species. As with many other species of tubenoses, the "field marks" for identification at sea away from the breeding sites depend as much (or more) on factors such as flight style than on details of the plumage. Like other species in the "small black-and-white" shearwater complex, Galapagos Shearwaters fly low and quickly, with very fast wing-beats interspersed with short glides. Separating this species from Black-vented (Puffinus opisthomelas) and Townsend’s (Puffinus auricularis) shearwaters, the two other species most-likely to be confused with it within its non-breeding range off Mexico and Central America, requires care, as all three species are quite similar.
Threats to this species are the standard ones for island-nesting seabirds unused to land-based predators: introduced cats and rats eat nestlings and adults in burrows; pigs uproot and destroy nesting sites; and goats consume any native vegetation that might provide cover for nesting sites. Fortunately, mammal control programs on its native nesting islands have successfully controlled populations of non-native predators, and nesting populations of the Galapagos Shearwater have stabilized. There is no information about at-sea threats to this species.