Family: Hydrobatidae, Storm-Petrels view all from this family

Description 7.5 - 9" (19-23 cm). W. 16 1/2-18" (42-45 cm). Intermediate in many respects between Wilson's and Leach's storm-petrels. Blackish-brown overall with pale wing bars and a clear, curved white band across rump; white on rump more extensive than on Leach's but less than on Wilson's (where white extends fully onto undertail coverts). Tail slightly forked, but this feature is difficult to discern at sea; legs do not extend beyond tail in flight. Wings thinner and more angular than Wilson's, but thicker and less angular than Leach's. Larger than Wilson's. Difficult to identify reliably at sea.

Habitat Open oceans in our area, especially warm water currents, such as Gulf Stream, well offshore.

Nesting 1 blunt oval egg, flat white with occasional pale red spots, in burrows on tropical islands. To maximize use of scarce nesting sites, some populations breed in sequential cycles, making alternate use of the same burrows. Breeding occurs throughout the year in various populations.

Range Breeds on tropical islands in Atlantic and Pacific oceans (incl. Hawaii, Galapagos, Cape Verde, Ascension, St. Helena, Madeira). Fairly wide pelagic dispersal in the Atlantic; in our coverage area, seen most regularly in Gulf Stream off North Carolina.

Voice Usually silent at sea.

Discussion Little known in North American waters until the 1980s, when pelagic bird expeditions ventured into deeper Gulf Stream waters off North Carolina; now seen annually in this area. Flight pattern of Band-rumped differs both from the swooping swallowlike flight of Wilson's Storm-Petrel and from the buoyant, Nighthawklike flight of Leach's; Band-rumped flies with alternating quick wing beats and long horizontal zig-zag glides, reminiscent of a shearwater. Commonly feeds with wings held horizontal; seldom follows ships.