The Hawaiian petrel or ʻuaʻu is a large, dark grey-brown and white petrel that is endemic to Hawaiʻi.
Region
Central North Pacific
Typical Environment
Outside the breeding season this species ranges widely over the open ocean around and far beyond the Hawaiian Archipelago, often reaching productive offshore waters such as the California Current. During breeding it is tied to high-elevation colonies on islands including Maui, Hawaiʻi (Big Island), Kauaʻi, and Molokaʻi. It nests in burrows on steep volcanic slopes, alpine shrublands, and subalpine grasslands with sparse vegetation. At sea it forages over deep pelagic waters, often along frontal zones and upwellings where prey is concentrated.
Altitude Range
Sea level to 3000 m
Climate Zone
Tropical
Ease of Keeping
Beginner friendly: 1/5
The Hawaiian petrel, or ʻuaʻu, is a large gadfly petrel that nests in burrows high on Hawaiian volcanoes and forages far across the North Pacific. It is strictly nocturnal at breeding colonies, arriving and departing under cover of darkness to avoid predators. Major threats include introduced mammals, light disorientation, and collisions with power lines. Conservation programs use predator control and shielding of lights to protect colonies.
Temperament
nocturnal and secretive at colonies; solitary to loosely associated at sea
Flight Pattern
soaring glider with stiff wings, using dynamic soaring and rapid arcing turns
Social Behavior
Breeds colonially in burrows, with pairs forming long-term monogamous bonds. Adults arrive after dusk and depart before dawn to reduce predation. A single egg is laid, and both parents share incubation and chick-rearing, feeding the chick by regurgitation. Fledglings depart to sea on their own after several months.
Migratory Pattern
Seasonal migrant
Song Description
At colonies it gives eerie, moaning and wailing calls, the source of its Hawaiian name ʻuaʻu. Vocalizations carry over long distances at night and include rising and falling whistles and groans. Generally silent at sea.
Plumage
Dark gray-brown upperparts with a contrasting white belly and underwing, bordered by a narrow dark edge; dark cap and nape form a hooded look. Underwings appear mostly white with thin dark margins and a faint carpal bar; tail is dark and wedge-shaped.
Diet
Feeds primarily on squid and small fish, with some crustaceans. Often targets prey associated with diel vertical migration, taking them near the surface at night. Captures food by surface-seizing and shallow plunge-dives, sometimes following predatory fishes or marine mammals that drive prey upward. Opportunistic, concentrating foraging over productive fronts and upwelling areas.
Preferred Environment
Pelagic waters far offshore, typically beyond the continental shelf. Frequently forages along oceanic fronts, eddies, and the edges of upwellings where prey is aggregated.
