The wedge-rumped storm petrel is a storm petrel. It breeds in the Galápagos Islands and on the coast of Peru. It was formerly defined in the genus Oceanodroma before that genus was synonymized with Hydrobates.
Region
Eastern Tropical Pacific
Typical Environment
Occurs over warm, productive waters from the Galápagos and Peruvian upwelling zones across the eastern tropical Pacific. Strongly pelagic and typically far offshore except during the breeding season. Breeds on arid islands and coastal headlands, using burrows and rock crevices in lava or soft soils. Forages along current edges and upwelling fronts where zooplankton concentrates.
Altitude Range
Sea level to 500 m
Climate Zone
Tropical
Ease of Keeping
Beginner friendly: 1/5
A small, highly pelagic seabird, the wedge-rumped storm petrel is best recognized by its bright, wedge-shaped white rump against otherwise dark plumage. It breeds mainly in the Galápagos Islands and along the Peruvian coast, nesting in burrows or rock crevices and visiting colonies only at night. Formerly placed in Oceanodroma, it is now classified in Hydrobates. Threats include introduced predators at colonies and attraction to artificial lights.
Temperament
social and active at sea, secretive at colonies
Flight Pattern
short rapid wingbeats with brief glides; often patters on the water surface while feeding
Social Behavior
Nests in dense colonies, typically in burrows or crevices. Mostly nocturnal at breeding sites to avoid predators. Pairs are generally monogamous, laying a single egg; both sexes incubate and feed the chick by regurgitation.
Migratory Pattern
Partial migrant
Song Description
At sea it is usually silent. At colonies it gives chattering trills, purrs, and squeaky calls, most often under cover of darkness.
Plumage
Mostly sooty-brown to blackish with a crisp, wedge-shaped white rump; slender wings and a shallowly forked tail.
Diet
Takes small fish, squid, and abundant planktonic crustaceans such as copepods. Feeds by picking prey from the surface and by pattering while hovering. Often associates with predatory fish and marine mammals that drive prey to the surface and may follow fishing vessels. Likely uses olfactory cues, including dimethyl sulfide, to locate productive areas.
Preferred Environment
Open ocean over upwelling zones, fronts, and current lines where prey aggregates. Generally far offshore, approaching coastal waters mainly near colonies. Frequently forages around convergence lines and floating debris where plankton concentrates.
