Nunulu – Bonin Petrel
Pterodroma hypoleuca
| Stated-recognized | Indigenous |
| North American Waterbird Conservation Plan |
Moderate concern |
| Regional Seabird Conservation Plan |
USFWS 2005 |
The Nunulu, also known as the Bonin Petrel, is a small, nocturnal bird from the gadfly petrel family (Procellariidae). It breeds farther north than any of its Pacific relatives. Like many pelagic seabirds, Bonin Petrels have dark upperparts and light underparts, with both sexes having a similar appearance. They are known for their fast and highly maneuverable flight compared to other petrel species.
Bonin Petrels typically forage far offshore and catch prey while resting on the water or hovering. They usually forage alone but may join mixed-species flocks. Unlike most other species in the same genus, Bonin Petrels primarily feed on fish, including lantern fishes (Myctophidae) and hatchetfishes (Sternoptychidae). However, squid (Ommastrephidae) is also an essential part of their diet.
These birds are winter breeders, in contrast to the only other gadfly petrel that breeds in Hawai‘i, known as ‘ua‘u or Hawaiian Petrel (P. phaeopygia), which nests in the summer. Like most seabirds, Bonin Petrels breed in their natal colonies, form long-term pair bonds, and show high site fidelity. They lay only one egg per season, and both parents are involved in all aspects of raising their young.
Bonin Petrels nest in burrows that they dig in sandy soils. In Hawai‘i, eggs are usually laid in mid-January, and chicks fledge by June. They compete with the larger ‘ua‘u kani, or Wedge-tailed Shearwater (Puffinus pacificus), for burrows. Unfortunately, late-fledging petrel chicks are sometimes killed by returning shearwaters.
Bonin petrels breed in the Northwestern Hawaiian Islands from French Frigate Shoals to Kure Atoll. Historically bred on the Main Hawaiian Islands. Outside of Hawai‘i, breeding populations are restricted to Bonin and Volcano islands off of Japan. Outside the breeding season, a few individuals remain in the waters surrounding the Hawaiian Islands, but most disperse widely, mainly between Hawai‘i and Japan.
The following management goals are essential to Pacific seabird conservation: maintain, protect, and enhance habitat; eradicate or control non-natives; minimize bycatch and other adverse effects of fishing; improve the effectiveness of oil spill response efforts; identify contaminants and hazardous substances; and minimize the impact of powerlines, towers, wind turbines, and lights (USFWS 2005). The goal of these management actions is not only to protect seabird populations and their breeding colonies, but also to re-establish former breeding colonies, thereby reducing the risk of extinction.
Introduced Predators: Like all seabirds, adults and their nests are vulnerable to predation by rats (Rattus spp.) and feral cats (Felis silvestris). Fortunately, all sites in the Northwestern Hawaiian Islands (NWHI) are free from both rats and cats.
Invasive Species: On Lisianski and Laysan Islands, rabbits (Oryctolagus cuniculus) have severely reduced suitable nesting locations by denuding the vegetation. Additionally, Golden Crown-beard (Verbesina encelioides) further degrades these crucial nesting habitats. At Kure, introduced Big-headed Ants (Pheidole megacephala) may contribute to nestling mortality and facilitate the destruction of native vegetation by supporting a non-native scale insect.
Nunulu Name Press Release
Nunulu is the name chosen for the bonin petrel. Nunulu means growling, warbling, or reverberating. The word nunulu can be found within the chant Nā ʻAumākua; specifically “Nunulu i ka lani.” This line refers to a sky that is immensely filled with activity, causing it to reverberate. Nunulu was chosen because of the annual migratory return flight home of the bonin petrels to the islands where on the first couple days of their return, the skies are so filled with birds that it blackens the sky. This imagery was an important aspect to preserve with this species, as the birds’ habitat is threatened by climate change. The nunulu is one of several birds being actively translocated to the James Campbell National Widlife Refuge in Kahuku, Oʻahu, from PMNM to help combat this threat.
What’s in a Name?
A webinar related to the research of the Papahānaumokuākea Native Hawaiian Cultural Working Group tasked with giving Hawaiian names to numerous other bird, plant, limu, and coral species unique to PMNM
