Polynesian Storm-Petrel
Nesofregetta fuliginosa
Procellariiformes Order – Oceanitidae Family
INTRODUCTION:
The Polynesian Storm-Petrel is a pelagic species found in tropical central and western Pacific Ocean. It is usually seen in Chile, French Polynesia, Kiribati, New Caledonia, Vanuatu, Fiji and Samoa.
It breeds on remote Pacific islands, atolls or stacks, among boulders or vegetation. This species is a colonial breeder. It uses both burrows and rocky crevices for nesting, but also tussocks of grass, depending on the location.
It feeds on marine food items such as cephalopods, small fish and crustaceans. It forages on the wing, and dives to catch the prey.
It is the only species placed in the genus Nesofregetta, and is markedly polymorphic. The morph frequency varies with the range.
The Polynesian Storm-Petrel is threatened by invasive species such as cats and rats on the breeding islands. Habitat loss is caused by agriculture and rabbits. Climate change and variation of the sea-level have a negative impact on these birds.
The species is currently listed as Endangered.
DESCRIPTION OF THE BIRD:
Biometrics:
Length: 24-26 cm
Weight: 56-86 g
The Polynesian Storm-Petrel is the largest storm-petrel, characterized by black bill, broad and rounded wings, long, notched tail and black feet.
The typical pale morph has blackish upperparts, with slightly browner mantle, back, scapulars and uppertail-coverts. Flight-feathers and tail are blacker. The white uppertail-coverts form a contrasting, narrow horseshoe. On the upperwing, the white tips of the greater secondary-coverts form a pale wingbar.
On the underparts, the white chin and throat form a partial pale collar extending over the neck side and sometimes meeting on the nape. It contrasts with a broad, blackish pectoral band, itself contrasting with the white belly and flanks.
On the underwing, flight-feathers and lesser coverts are blackish, whereas the white median and greater coverts form a contrasting, pale central panel. Both greater and median primary-coverts may appear largely dark. The black pectoral band joins the black leading edge.
The undertail-coverts are mostly dark. Some faint, dark grey streaks may appear on the white uppertail-coverts and belly.
In the intermediate morph, these dark marks may be larger and more conspicuous, and form a continuous gradation between the other two morphs.
The dark morph is entirely blackish-brown, except a pale wingbar.
The bill is black.
The eyes are dark brown.
Legs and webbed feet are black, but the webs are sometimes paler.
Male and female are similar.
The juvenile resembles adult.
RANGE:
The Polynesian Storm-Petrel occurs across a large range of Pacific locations such as Chile, French Polynesia, Kiribati, New Caledonia, Vanuatu, American Samoa, Fiji and Samoa.
The species breeds in tropical S Pacific, from New Caledonia and Kiribati (Gilbert Is, Phoenix Is and Kiribati) E to Marquesas, Gambier and Salas y Gomez Island.
It is known to migrate to other Pacific areas including Japan coastal waters, Philippines and Australia.
The morph frequency varies with the range. Some islands only have pale morph. The dark morph can be seen on Samoa, whereas the intermediate morph which is a combination of both previous morphs occurs on Phoenix Is and Line Is.
HABITAT:
The Polynesian Storm-Petrel is marine and pelagic, spending most of its time at sea.
But during the breeding season, the colonies are established on remote Pacific islands, atolls or stacks, coral or volcanic islands. The species can also be seen along rocky or sandy shores.
The nest is placed in rock crevice or burrow among boulders, but also on the ground among the vegetation.
CALLS AND SONGS: SOUNDS BY XENO-CANTO
The Polynesian Storm-Petrel’s vocalizations are poorly known. Only one sound is reported for this species, described as a soft, guttural “grrr, grrr, grrr”.
The storm-petrels are usually silent at sea, but competition for food may involve series of repeated peeping and chattering sounds. They become more vocal at the colonies.
BEHAVIOUR IN THE WILD:
The Polynesian Storm-Petrel feeds mainly on cephalopods, small fish and crustaceans, and some recent observations also indicate insects Halobates.
It often feeds while flying. It can be seen pattering and dipping to catch a prey. Some shallow dives are also observed.
The Polynesian Storm-Petrel comes ashore for breeding. It is a colonial nester and forms loose colonies on remote Pacific islands. It nests in burrows or rock crevices, and sometimes on the ground in tussocks of grass, especially on Gambier. The colonies are regularly visited, but mainly at night. Both adults share all the nesting duties.
The Polynesian Storm-Petrel probably disperses after the breeding season, mainly over adjacent waters, but also E to warm waters of South Equatorial Current, between 10°N and 10°S.
It has been recorded in Australian waters over Norfolk Ridge, and more recently in pelagic trip off Queensland, NE Australia.
The Polynesian Storm-Petrel exhibits a distinctive zig-zag pattern in flight. In a fair wind, the bird springs up from the water while the legs and dangling. It circles on broad, stiff wings before falling back to the water and repeating the same process. During the flight, the feet are dangling loosely or project beyond the forked tail.
REPRODUCTION OF THIS SPECIES:
The Polynesian Storm-Petrel breeds throughout the year, depending on the range: August/December on Christmas Islands, July/December in Marquesas. The laying could be more concentrated in Southern Spring (August/December) on Gambier, Rapa and Salas y Gomez Island.
The species forms loose colonies where the birds nest in burrows or rock crevices, although on Gambier, they nest more often in tussocks of grass than in burrows, and sometimes in the open. They return to the colonies mainly by night, after spending the day foraging at sea.
The female lays a single egg. The incubation lasts about 50 days. Both parents share the nesting duties. They feed and protect the chick until it fledges, about 60 days after hatching.
PROTECTION / THREATS / STATUS:
The Polynesian Storm-Petrel has very small, fragmented population, still decreasing. Despite eradication at some locations of invasive species (cats, rats, dogs, mongoose…), they remain an important threat for the nesting birds and their chicks.
Following eradication of invasive rats, the Polynesian Storm-Petrel has returned to Kamaka Island in French Polynesia, involving ecological benefits such as soil fertility supporting healthier crops.
The size of the population is estimated at just 250-999 mature individuals.
The Polynesian Storm-Petrel is currently classified as Endangered.
Fr: Océanite à gorge blanche
Ang: Polynesian Storm-Petrel
All: Weißkehl-Sturmschwalbe
Esp: Paíño Gorjiblanco
Ita: Uccello delle tempeste di Polinesia
Nd: Witkeelstormvogeltje
Sd: polynesisk stormsvala
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
OISEAUX DE MER – Guide d’identification de Peter Harrison – Editions Broquet (Canada) – ISBN-10 : 2890004090 – ISBN-13 : 978-2890004092
Polynesian Storm-petrel Species Overview
BESTLife 2030 - Polynesian storm-petrels return to Kamaka Island: A triumph for Pacific conservation
oceanographic - Polynesian storm-petrel returns home after 100 years
MONGABAY - Endangered seabirds return to Pacific island after century-long absence
NatureFiji - Polynesian Storm Petrel (Nesofregetta fuliginosa)
A first for Australia: Polynesian Storm-petrel
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