Tahiti Petrel
Pseudobulweria rostrata
钩嘴圆尾鹱
Introduction
A medium-sized seabird belonging to the family Procellariidae, endemic to the Pacific Ocean. The species comprises two subspecies: P. r. rostrata breeding in the west-central Pacific, and P. r. trouessarti breeding in the tropical and subtropical Pacific. It is the most studied member of the Pseudobulweria genus, which includes three critically endangered species. The bird breeds at high elevations in volcanic island mountains and forages by seizing prey at the water surface rather than diving. Classified as near threatened by the 2018 IUCN Red List, with major threats from introduced predators (rats, cats, pigs, dogs), nickel mining, and coastal light pollution.
Description
A medium-sized petrel weighing 315-506 g with a wingspan averaging 104.5 cm and body length of 38-42 cm. The species has a wedge-shaped tail, long wings held straight and perpendicular to the body, an extended neck, and a small head with a black, stout, bulbous bill and dark brown eyes. The dark elongated body features a white abdomen. Adults are predominantly dark brown with darker hoods and paler rumps, while underwings display a faint white line along the middle with slightly paler flight feathers. Juveniles resemble adults, though females typically have smaller measurements.
Identification
The most reliable field mark is the narrow wings held straight and fully perpendicular to the body, resembling albatross flight behavior. This distinguishes it from the Phoenix petrel, which holds wings more forward and bent. Phoenix petrels also have a larger bill, lack the white underwing line, and possess paler tails. The Atlantic petrel, occasionally confused due to its similar white abdomen, can be identified by its brown undertail, dark eye patch, and plain underwings. At long ranges, identification becomes challenging due to overlap with other petrel species.
Distribution & Habitat
Breeding distribution includes American Samoa, Gambier Islands, Marquesas Islands, and Society Islands for P. r. rostrata, with potential breeding on Rarotonga in the Cook Islands. P. r. trouessarti breeds in New Caledonia and Vanuatu. Non-breeding individuals occur in Australia, Guam, and the Federated States of Micronesia. Vagrants have been recorded across South and Central America, Asia, and Oceania including Chile, Colombia, Costa Rica, Ecuador, Japan, Peru, Philippines, and numerous Pacific islands. The species inhabits shallow and oceanic marine environments with surface temperatures exceeding 25°C, as well as shrubland and forest habitats on volcanic islands.
Behavior & Ecology
Breeding occurs year-round with peak egg-laying between March and July and fledging between July and September. Nests are established at high elevations in mountains or forests on volcanic islands, utilizing crevices and burrows up to 1,900 m elevation. Diet consists of surface-seized prey including sea skaters, with gut contents revealing deep pelagic fish, cephalopods, and benthopelagic species such as hatchetfish, snake mackerels, and silver scabbardfish, indicating scavenging on dead organisms or nighttime vertical migration of prey. Feeding associations occur with other seabirds and pilot whales. P. r. rostrata produces elaborate multi-part calls with staccato introductory notes and hooting endings, while P. r. trouessarti performs up-slurred whistles in flight and braying calls on the ground.
Conservation
Classified as near threatened by the 2018 IUCN Red List. The global population is estimated at 10,000-19,999 mature individuals with 20,000-30,000 total individuals. A 35% population decrease occurred in the eastern tropical Pacific between 1988-2000 and 1998-2000. Breeding populations are declining in the Marquesas (<500 pairs), Tahiti (<1,000 pairs), and Mo'orea (several thousand pairs). Threats include feral cats and introduced rats affecting P. r. rostrata, while P. r. trouessarti faces predation from feral pigs and dogs, nickel mining, and coastal light pollution causing juvenile mortality. Competition with Wedge-tailed Shearwaters for burrows has been recorded. Conservation actions include mining reduction planning in New Caledonia and light pollution rescue programs.
Source: Wikipedia · CC BY-SA 3.0
Taxonomy
- Order
- Procellariiformes
- Family
- Procellariidae
- Genus
- Pseudobulweria
- eBird Code
- tahpet1
Subspecies (2)
-
Pseudobulweria rostrata rostrata
breeds American Samoa, Society, Marquesas, and Gambier islands (southeastern Tuamotu Islands); confined to tropical Pacific; ranges to tropical Pacific Ocean waters off New Guinea and northeastern Australia to coasts of Mexico and Central America
-
Pseudobulweria rostrata trouessarti
breeds New Caledonia and perhaps Fiji; ranges southern Pacific Ocean
Data Sources
Species description from Wikipedia, licensed under CC BY-SA 3.0.
Taxonomy data from AviList 2025.