Black-bellied Storm-Petrel Fregetta tropica Scientific name definitions

The Black-bellied Storm-Petrel is very closely related to the White-bellied Storm-Petrel (Fregetta grallaria), but as the name implies, their belly color is different (though this does depend on subspecies). In addition to differing in plumage, the two species also differ in habitat preference, with Black-bellied Storm-Petrel preferring colder waters and breeding to the south of White-bellied Storm-Petrel, making it is a true sub-Antarctic breeder. Fregetta storm-petrels are generally grayish or blackish above, with a black hood, dark upperwings and tail with a pale carpal bar and white wing linings as well as largely white underparts below the hood. Black-bellied Storm-Petrel shows a bold black central belly stripe, although in the field this can be difficult to see in profile with dark water as a background. Black-bellied Storm-Petrel also has longer legs (which project beyond the tip of the tail in flight), and darker upperparts than White-bellied Storm-Petrel. Members of the genus Fregetta all forage in an unusual manner, skipping off waves using one leg, in an asymmetrical skip. Black-bellied Storm-Petrel occurs in the Pacific, Indian, and Atlantic Ocean basins. When not breeding, it migrates north, although its nonbreeding distribution is not well known.