Tahiti Petrel

Identificazione

Adult Tahiti petrels are between 315 and 506 g and have wingspans averaging 104.5 cm long whereas their overall length is between 38-42 cm. The species is identifiable by its wedge-shaped tail, long wings and neck, small head, black, stout, and bulbous bill, dark brown eyes, and dark elongated body with white abdomen. In addition, adults are mostly dark brown with darker hoods and paler rumps. Their underwings have a faint white line along the middle with slightly paler flight feathers. Juveniles are similar to adults in plumage and females usually have smaller measurements.

Tassonomia

In 1848, Peale collected and described the first specimen of this species in Tahiti. Then, in 1917, the Tahiti petrel was separated into two subspecies: rostrata and trouessarti, due to trouessarti's more robust bill. Not only is there a physiological difference between the two, they are also found in different geographic locations. P. r. rostrata, the nominate subspecies, breeds in the west-central Pacific Ocean whereas P. r. trouessarti breeds in the tropical and subtropical Pacific Ocean. Also, after originally being classified as Pterodroma, genetic studies showed that the bird is instead a part of the Pseudobulweria genus. Furthermore, this study showed species distinction between the Mascarene petrel (Pseudobulweria aterrima) and the Tahiti petrel (Pseudobulweria aterrima) by analyzing phylogenetic histories. Indeed, the genus includes the Tahiti petrel, Beck's petrel (Pseudobulweria becki), the Fiji petrel (Pseudobulweria macgillivrayi), the Mascarene petrel (Pseudobulweria aterrima), and the Saint Helena petrel (Pterodroma rupinarum) which is now extinct. Similarly to the Mascarene petrel before gene analysis, Beck's petrel is currently considered a member of the Tahiti petrel species by some scientists due to the lack of specimens for research.

Nome scientifico

Pseudobulweria rostrata

Autorità

(Peale, 1849)

Ordine

Procellariformi

Famiglia

Procellaridi

Genere

Pseudobulweria

Areale e habitat

Despite its name, the Tahiti petrel is found across the Pacific Ocean. As discussed earlier, the subspecies breed in different areas of the ocean:<p>P. r. rostrata - Confirmed to breed in the American Samoa, Gambier Islands, Marquesas Islands, and Society Islands. Potentially breeds on Rarotonga of the Cook Islands as well.<p>P. r. trouessarti – Confirmed to breed in New Caledonia and Vanuatu.<p>Their non-breeding geographic distribution is Australia, Guam, and the Federated States of Micronesia. However, vagrant individuals have been identified all over South and Central America, Asia, and Oceania as seen below.<p>Vagrants have been found in Chile, Colombia, Costa Rica, Ecuador, El Salvador, French Southern Territories, Guatemala, Indonesia, Japan, Kiribati, Marshall Islands, Nauru, Nicaragua, Niue, Norfolk Island, Northern Mariana Islands, Palau, Panama, Papua New Guinea, Peru, Philippines, Pitcairn, Samoa, Tokelau, Tonga, Tuvalu, United States Minor Outlying Islands, and Wallis and Futuna.<p>The Tahiti petrel requires both terrestrial and marine systems and is often found in both shallow and oceanic marine habitats as well as shrubland and forest habitat types. In terms of marine habitats, they prefer water with surface temperatures higher than 25°C. Consequently, El Niño events may have an influence on their abundance in waters of the East Pacific.

Areale riproduttivo

PO : Grande Terre (New Caledonia), Gau (Fiji; sw Polynesia), American Samoa (c Polynesia), Society, Marquesas and Gambier is. (se Tuamotu Is.; e Polynesia)

Areale non riproduttivo

to tropical Pacific Ocean waters off New Guinea and n Australia, and ec Pacific coast of Mexico and Central America

Migrazione

Migratori completi

Comportamento

Comportamento migratorio: Migratori completi.

Conservazione

Tendenza della popolazione: in diminuzione.

Tendenza della popolazione

in diminuzione