Tahiti Petrel

The Tahiti petrel, scientifically known as Pseudobulweria rostrata, is a medium-sized seabird with a dark brown and white plumage. This species, which graces the Pacific Ocean, is distinguished by its wedge-shaped tail, long wings and neck, and a small head. The adult Tahiti petrel's bill is black, stout, and bulbous, complemented by dark brown eyes and an elongated body with a contrasting white abdomen.

Identification Tips

When observing the Tahiti petrel, look for its mostly dark brown plumage with a darker hood and a paler rump. The underwings feature a faint white line along the middle with slightly paler flight feathers. Juveniles share a similar plumage to adults, and females are generally smaller in size. At a distance, the species can be challenging to distinguish from other petrels, but its narrower wings, which are fully perpendicular to the body and straight in flight, are a key identifier.

Habitat

The Tahiti petrel is an inhabitant of both terrestrial and marine ecosystems, often found in shrubland and forest habitats as well as shallow and oceanic marine environments. They show a preference for waters with surface temperatures above 25°C.

Distribution

This species is widespread across the Pacific Ocean, with two subspecies: P. r. rostrata breeding in the west-central Pacific and P. r. trouessarti in the tropical and subtropical Pacific. Their non-breeding range extends to Australia, Guam, and the Federated States of Micronesia, with vagrant individuals reported in various regions across South and Central America, Asia, and Oceania.

Behaviour

The Tahiti petrel is known to lay eggs at high altitudes in mountains or forests, favoring volcanic islands for breeding. They breed throughout the year, with a peak in egg-laying from March to July. The chicks are typically ready to fledge between July and September.

Song & Calls

The vocalizations of the Tahiti petrel are quite elaborate, with P. r. rostrata producing a series of whistles ending in a hooting sound when in flight or on breeding grounds. The subspecies P. r. trouessarti is known for its up-slurred whistles in flight and braying whistles on the ground.

Breeding

Breeding sites for the Tahiti petrel are located at various elevations, with nests in crevices and burrows. The breeding biology of the species is not well-documented, with little data on incubation or chick-rearing.

Similar Species

The Tahiti petrel can be confused with the Phoenix petrel and the Atlantic petrel, but differences in bill size, wing posture, and underwing markings can help distinguish them.

Diet and Feeding

The diet of the Tahiti petrel is not well understood, but they are known to feed on surface prey such as sea skaters and have been observed scavenging on deep-sea fish that rise to the surface at night.

Conservation status

The Tahiti petrel is currently classified as Near Threatened by the IUCN Red List of Threatened Species. The genus Pseudobulweria is considered the most endangered among seabirds, with several species critically endangered. Population trends are generally unknown, but declines have been noted in certain breeding areas.

Population trends

Estimates suggest there are between 10,000–19,999 mature individuals, with a total population of 20,000–30,000. A significant decrease in individuals in the eastern tropical Pacific was noted between 1988–1990 and 1998–2000.

Threats

The species faces threats from introduced predators such as rats and feral cats, as well as habitat disturbances from nickel mining and light pollution. Competition for nesting burrows with other seabirds is also a concern.

Conservation actions

Efforts are underway to mitigate the impact of mining and light pollution, with campaigns to rescue and release disoriented birds. Continued census and monitoring are essential to better understand and address the conservation needs of the Tahiti petrel.