The ashy storm petrel is a small, scarce seabird of the storm petrel family Hydrobatidae. It breeds colonially on islands off the coasts of California and Mexico, and is one of six species of storm petrel that live and feed in the rich California Current system.
Region
California Current, Eastern North Pacific
Typical Environment
Breeds on offshore islands off California and northern Baja California, including the Farallon Islands, Channel Islands, and Coronado Islands. At sea it ranges over shelf and slope waters within the California Current, usually remaining relatively close to the breeding region year-round. It forages over upwelling zones, offshore fronts, and eddies where krill and small fish concentrate. Nests are placed in rock crevices, talus slopes, and occasionally in burrows or artificial cavities on predator-free islets.
Altitude Range
Sea level to 300 m
Climate Zone
Temperate
Ease of Keeping
Beginner friendly: 1/5
This small, smoky-gray storm-petrel is largely confined year-round to the productive California Current. It breeds at night in rock crevices and talus on offshore islands, laying a single egg and raising one chick per season. Populations are vulnerable to light pollution, ocean-warming events, and predation by gulls and Burrowing Owls at colonies. Individuals are long-lived for their size, often surviving two decades or more.
Egg (coll.MHNT)
Temperament
pelagic and wary; social at breeding colonies
Flight Pattern
buoyant with short rapid wingbeats and brief glides, skimming low over waves
Social Behavior
Highly colonial, nesting in dense aggregations on small rocky islands. Strictly nocturnal around colonies, arriving and departing under cover of darkness to avoid predators. Monogamous pairs lay a single egg and share long incubation and chick-rearing duties.
Migratory Pattern
Resident
Song Description
At colonies delivers soft, purring trills and chattering calls from within crevices. Vocal activity peaks at night, aiding pair contact and territory maintenance in the dark.
Plumage
Uniform sooty to ashy gray with slightly paler underwing coverts; overall smooth, matte appearance with no contrasty rump patch.
Diet
Feeds mainly on zooplankton such as krill, along with small fish, squid, and other pelagic invertebrates. Takes prey from the surface by picking while on the wing and occasionally by pattering on the water. Often concentrates where upwelling brings nutrients to the surface, and may associate with marine mammals or schools of predatory fish that drive prey upward.
Preferred Environment
Typically forages over continental shelf and slope waters within the California Current, especially along fronts and eddies. Most common in areas of strong upwelling and convergences where prey is concentrated.
