The Bonin petrel or nunulu is a seabird in the family Procellariidae. It is a small gadfly petrel that is found in the northwest Pacific Ocean. Its secretive habits, remote breeding colonies and limited range have resulted in few studies and many aspects of the species' biology are poorly known.
Region
Northwest Pacific Ocean
Typical Environment
Breeds mainly on remote oceanic islands, including the Northwestern Hawaiian Islands and parts of the Ogasawara archipelago. At sea it occupies pelagic waters far from land, ranging over subtropical and tropical currents. Nesting occurs on low coral atolls and volcanic islands with friable soil suitable for burrowing, often under grass or low shrubs. Foraging typically occurs over deep waters where prey ascends toward the surface at night. It is rarely seen close to mainland coasts except during storms.
Altitude Range
Sea level to 300 m
Climate Zone
Subtropical
Ease of Keeping
Beginner friendly: 1/5
The Bonin petrel is a small gadfly petrel that nests in burrows and visits colonies only at night, likely to avoid aerial predators like frigatebirds. Many colonies suffered historic declines from introduced rats and cats, but predator control and island restoration have led to notable recoveries. Outside the breeding season it ranges widely over the northwest Pacific. Its tubenose helps it excrete excess salt, allowing long periods at sea.
A Bonin petrel trapped in the sand on Midway Atoll by the 2011 Tōhoku earthquake and tsunami, before being rescued.
Bonin petrel chick
Temperament
secretive and nocturnal around colonies
Flight Pattern
soaring glider with agile shearing arcs and quick, stiff wingbeats
Social Behavior
Breeds in dense colonies, nesting in burrows that may be reused year after year. Pairs are generally monogamous, sharing incubation and chick-rearing duties. Colony activity peaks at night, with birds arriving and departing under cover of darkness. Chicks are fed oily regurgitations until fledging.
Migratory Pattern
Seasonal migrant
Song Description
Around colonies it gives soft moans, chatters, and wailing calls, most often at night. At sea it is usually silent. Vocal exchanges help pairs locate each other and maintain burrow ownership in darkness.
