Christmas Shearwater
Puffinus nativitatis
Procellariiformes Order – Procellariidae Family
INTRODUCTION:
The Christmas Shearwater is the darkest shearwater, with its entirely blackish-brown plumage, dark brown eyes, black bill and legs.
This species breeds on remote sandy islands where the colonies are established. During the breeding season, it can be found from eastern Micronesia and Hawaiian Islands, SE across Polynesia, dispersing nearly throughout the tropical Pacific. The nest is often placed under vegetation or in rock crevice. Both adults share the nesting duties. They are believed to be monogamous. They leave the colonies after breeding and return in the spring.
It feeds on fish, squid, crustaceans and marine worms, caught from the surface or by diving into shallow waters.
The Christmas Shearwater is named for Christmas Island (now known as Kiritimati), close to the Equator and south of the Hawaiian Islands.
The species has very large range and the population is suspected to be stable. It is mainly threatened by potential future rises in sea-levels resulting from climate change, but currently, the Christmas Shearwater is not globally threatened.
DESCRIPTION OF THE BIRD:
Biometrics:
Length: 35-38 cm
Wingspan: 83-90 cm
Weight: 324-354 g
The Christmas Shearwater has dark brown plumage overall, but the upperparts are darker than the underparts.
On the upperwing, the edges of the wing-coverts and the inner webs of the primaries are paler brown. The tail is short and wedge-shaped, with silvery tinge on the twelve graduated rectrices.
On the underwing, the underside of the primaries shows a dull silvery flash.
On the dark brown head, we can see two white filoplumes on the nape. On the chin, the feathers are edged with white.
The short bill is shiny black, slender and slightly hooked at tip. The tubular nostrils are well visible on the upper mandible.
The eyes are brown, with narrow white eyelids.
The legs are entirely brownish-black, with somewhat paler webs, inner toes and inner tarsus. The claws are black.
Male and female have similar appearance.
The juvenile resembles adult.
The chick has sooty-brown down.
RANGE:
The Christmas Shearwater generally occurs in the central Pacific where it breeds on remote islands, from Hawaiian Islands in the north, south to Phoenix Islands (Republic of Kiribati), and east to Marquesas Islands, Easter Island and Salas y Gomez. The species has become locally extinct on several islands, including Wake Island.
Outside of the breeding season, it ranges throughout the Pacific, having been recorded off the coast of Mexico and Guatemala in the east, and Bonin Islands in the west.
It is rare further south. It has been recorded off Fiji only twice (one time in early to mid-May).
The species is probably regular at least west to the Mariana and Iwo Islands, with multiple reports along the coast of Honshu (the largest island of Japan).
HABITAT:
The Christmas Shearwater is marine and pelagic outside of the breeding season. It prefers warm waters, but keeps away from land, except in the vicinity of the colonies.
On the oceanic sandy islands where it breeds, the nests are usually found among rocks or in lava fields, depending on the range. The nest is generally placed under dense vegetation because both eggs and chicks must be in the shade. They can be seen also in rock crevices or in abandoned burrows, and sometimes on steep grassy slopes.
CALLS AND SONGS: SOUNDS BY XENO-CANTO
The Christmas Shearwater is mainly vocal during the breeding season on land. Several sounds are related to courtship and pair formation, but also to defence of the territory.
The main call includes one excited rolling note, then three short notes, and a long, drawn-out moan. Other following notes vary, sometimes ending with a high-pitched cry. We can also hear several quiet chitterings and moans.
The birds are more active at night and during 3-4 hours after sunrise, usually in flight while circling above the breeding grounds near the nest-site.
The main call is given in flight. On the ground, the pairs call in duet or one after the other.
BEHAVIOUR IN THE WILD:
The Christmas Shearwater is highly pelagic. It tends to forage in large mixed-species flocks, taking prey driven towards the surface by groups of predatory fish such as tunas and also dolphins. It remains about 10-15 metres above the water before to fly down to catch the prey.
It feeds primarily on squid, fish (flying fish) and goatfish (Mullidae). It also takes crustaceans and marine worms.
It catches the prey from the water surface by snatching it up while floating along with the current, but it may also dive into shallower waters. It may occasionally hunt while flying, dipping down or picking prey from the surface while in flight.
An observation on Kure Atoll in the North-western Hawaiian Islands, talks about the sub-surface foraging behaviour of the Christmas Shearwater. Individual maximum depths were 10-24 metres, averaging 15 metres. The deepest and longest dive reached 24 metres and lasted 31 seconds. This behaviour was observed during the day, and especially at dusk.
The Christmas Shearwater is believed to be monogamous, at least during the breeding season, or more. The courtship displays occurs at dawn, before foraging for the rest of the day. At the beginning of the breeding season, the birds become noisy and busy, preparing the nest-site while performing mutual preening to strengthen the pair-bonds.
The nest is built on slopes, hillsides or lava fields, depending on the island. It is made on the ground with some plant material, often protected by dense vegetation. Both parents share all the nesting duties.
The Christmas Shearwater migratory behaviour is not well known. It may be resident at or near the breeding colonies, or a short- to medium-distance migrant.
The species probably disperses over tropical and subtropical waters, although some populations have been observed feeding within 400 km from their breeding colonies.
At the end of the breeding season, they probably move to nearby waters in October/November, but they disperse from the Hawaiian waters during the non-breeding period.
Some marine observations suggest that this species disperses south and east of its breeding islands after breeding. They generally return to the breeding islands in spring.
The Christmas Shearwater flies with rapid wingbeats on stiff wings. While flying low over the water surface, the wingbeats are interspersed with long glides. However, it is often observed flying in leisurely way, making it very similar to a petrel.
In strong wind, it flies higher above the waves and with active wingbeats.
REPRODUCTION OF THIS SPECIES:
The breeding season varies depending on the range. The nest-building usually starts early to late March, there or four weeks after the return to the nesting colonies.
The Christmas Shearwater nests on remote Pacific islands where the colonies are established. The nest-site is usually under dense vegetation on grassy slopes, rocky hillsides or lava fields, depending on the location of the breeding island.
But the nest needs to be in the shade. It is sometimes placed in rock crevice, wooded debris, or in abandoned petrel burrow. This species may also shape a tunnel through the thick vegetation, but it does not dig the soil to make a burrow.
The nest is a shallow scrape with some plant material such as twigs, leaves and other vegetation, but the structure is very simple.
The female lays a single, white egg per year. Both adults have an incubation-patch, and share the incubation lasting 48-54 days, by taking turns of 4-5 days.
At hatching, the chick has sooty-brown down. It is brooded continuously during one week after hatching, and then, only for short periods during the day, probably after being fed. Both parents return at night for the first 4-6 weeks, but later, only one adult returns to the nest.
The chick is fed by its parents, eating stomach oil and partially digested fish. It is fed as often as once every 24 hours during the first two months of its life. The young bird usually fledges 100-120 days after hatching, involving leaving the nest, feeding alone and socializing with other juveniles.
The fledgling is fairly similar to the adults, and weighs about 400 grams.
PROTECTION / THREATS / STATUS:
Like numerous seabirds breeding on remote islands, the Christmas Shearwater is threatened by possible future rises of sea-levels. Numerous colonies have declined and are still threatened by introduced mammal predators such as rats, cats and dogs, including humans, and by degraded areas in some parts of the islands, reducing the suitable nesting habitat.
The size of the population is estimated at around 150,000 individuals. It is currently considered to be stable.
The Christmas Shearwater is currently evaluated as Least Concern.
Fr: Puffin de la Nativité
Ang: Christmas Shearwater
All: Weihnachtssturmtaucher
Esp: Pardela de Navidad
Ita: Berta di Christmas
Nd: Kleine Wigstaartpijlstormvogel
Sd: brunlira
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
A Complete Guide to Antarctic Wildlife by Hadoram Shirihai and Illustrated by Brett Jarrett - Edited by Guy M. Kirwan - ALUL.A Press Oy, Finland - ISBN 9519894705
National Marine Sanctuary Foundation
UNDERWATER BEHAVIOR OF CHRISTMAS SHEARWATERS PUFFINUS NATIVITATIS FROM KURE ATOLL
Christmas Island Shearwater Pui4lnus nativitatis on Curtis Island
Wikipedia, the free encyclopaedia