Vanuatu Petrel
Pterodroma occulta
Procellariiformes Order – Procellariidae Family
INTRODUCTION:
The Vanuatu Petrel is endemic to Vanuatu as a breeding species, and occurs only in Banks Islands.
According to some authors, this species is now lumped within the White-necked Petrel from which it differs by smaller size of wings and tail, and some different colours on the underwing.
The population is apparently small. It breeds in restricted range vulnerable to introduced predators.
DESCRIPTION OF THE BIRD:
Biometrics:
Length: 35 cm
Wingspan: 82 cm
Weight: 300-350 g
The Vanuatu Petrel has dark grey back, upperwing and tail, but the rump is darker. On the upperwing, we can see the typical black M-shaped pattern. The tail is black-tipped.
The underparts are mostly white, with a dark grey band extending from mantle to upper breast sides. The underwing is white with dark leading edge. The primaries are largely blackish, forming a dark wing tip. Underwing-coverts and axillaries are white.
On the black-capped head, forehead, lores and neck are white.
The bill is black. The eyes are dark brown. Legs and feet are yellowish-grey.
Male and female are similar. The juvenile is not described.
The Vanuatu Petrel differs from P. cervicalis by smaller size and smaller bill. It is only 5% smaller in wing length, and 2% in tail length.
However, these features are complicated by individual variations in both species.
RANGE:
The Vanuatu Petrel breeds only on Vanua Lava, Banks Islands, Vanuatu. The species probably occurs at sea across southern Melanesia.
Outside of breeding season, it is pelagic and forages over SW Pacific Ocean.
HABITAT:
The Vanuatu Petrel breeds on Mt Suretamatai, at about 590/600 metres of elevation on Vanua Lava. The burrow is on steep slopes.
CRIS ET CHANTS: SOUNDS BY XENO-CANTO
The Vanuatu Petrel calls mainly at nest-site. It gives a rapid, decelerating “kok-kok-kok-kok-kok-kok” and a drawn-out “toooooo-wip”.
Male and female have slightly different voices. When the male is calling from the burrow, its voice is clear whereas the female’s voice is mostly hoarse.
BEHAVIOUR IN THE WILD:
The Vanuatu Petrel feeds mainly on the wing by picking fish and squid near the water surface. The flying fish is caught in the air.
The species is mostly solitary and often occurs on the edges of flocks of boobies (Family Sulidae) and noddies (Family Laridae). It does not follow ships.
The Vanuatu Petrel nests in burrow. It is usually present at the breeding site between late January and early March.
The Vanuatu Petrel probably ranges widely throughout Pacific Ocean. Observations at sea are reported between Vanuatu and New Caledonia, off S and N Vanuatu. The species is probably more widely spread than previously thought.
The flight is graceful and effortless with few wingbeats. While pursuing flying fish, it glides at high speed in the air. Aerial pursuits may last up to 300 metres with sharp turns and zigzags.
REPRODUCTION OF THIS SPECIES:
The breeding season takes place from late January to early March. One egg was found on 21 February.
The Vanuatu Petrel nests in burrow on steep slopes. The burrow is about 70 centimetres long, tunnelled under rocks and boulders. The entrance is usually facing east. The burrows are concentrated in areas with more open vegetation, forming many small sub-colonies on Mt Suretamatai.
Information on clutch size and size and colour of the eggs is currently lacking. However, Pterodroma petrels usually lay a single white egg.
PROTECTION / THREATS / STATUS:
The Vanuatu Petrel is not recognized by Birdlife International as a full species.
The population appears to be very small, in the hundreds. The breeding area is vulnerable to introduced predators, and the species was formerly hunted for food by local people.
Following some authors, as a subspecies of the White-necked Petrel which is listed as Vulnerable, the Vanuatu Petrel on Vanua Lava supports its specific status.
But treated as separate species, it is probably more threatened because it has smaller population.
From observations of remains of Vanuatu Petrel, predators are present, including the Peregrine Falcon, feral cats and rats (Rattus species). In addition, tropical cyclones and volcanic activity are other potential threats for this species.
It is probably listed as Endangered.
Fr: Pétrel de Vanuatu
Ang: Vanuatu Petrel
All: Vanuatusturmvogel
Esp: Petrel de Vanuatu
Ita: Petrello delle Vanuatu
Nd: Vanuatustormvogel
Sd: vanuatupetrell
Text by Nicole Bouglouan
Sources:
HANDBOOK OF THE BIRDS OF THE WORLD vol 1 by Josep del Hoyo-Andrew Elliot-Jordi Sargatal - Lynx Edicions - ISBN: 8487334105
Birds of Melanesia: Bismarcks, Solomons, Vanuatu and New Caledonia Par Guy Dutson – Editeur : Bloomsbury Publishing, 2011 – ISBN: 1408152460, 9781408152461
Birds New to Science: Fifty Years of Avian Discoveries Par David Brewer – Editeur: Bloomsbury Publishing, 2018 – ISBN: 1472906292, 9781472906298 – 416 pages
Wikipedia, the free encyclopaedia
First observations at sea of Vanuatu Petrel
Vanuatu petrel (Pterodroma occulta) discovered breeding on Vanua Lava, Banks Islands, Vanuatu