The Juan Fernandez Petrel is named for the Juan Fernandez Archipelago, its only breeding site. Specifically this petrel breeds on the outer island, Alejandro Selkirk but it is highly migratory during the non-breeding season, ranging north to the Eastern Tropical Pacific. This is a large and long-winged Pterodroma petrel with grayish brown upperparts, extensively white underparts and a contrasting dark cap. At sea it overlaps broadly with the Galapagos Petrel (Pterodroma phaeopygia), which is similar in shape and size, although the Galapagos is darker above, more extensively black on the head and with a bolder dark stripe on the underwing. The IUCN lists this petrel as Vulnerable, the population is estimated at a sizeable 3 million birds, but there are various threats to the single nesting island such as feral goats, cats, dogs, and it is thought the population has declined in recent years, although a thorough study is needed to confirm this.