Christmas shearwater
A poorly known Pacific shearwater with remote nesting habits.
Wikipedia / Wikimedia Commons
The Christmas shearwater, also called the ʻaoʻū (Puffinus nativitatis), is a medium-sized seabird found in the tropical Central Pacific. Because it nests in remote locations and has rarely been studied at sea, relatively little is known about it. It belongs to an ancient branch of the small *Puffinus* group, and its only close living relative is the Galápagos shearwater (*P. subalaris*).
The species was first described and given its current scientific name by American naturalist Thomas Hale Streets in 1877. Genetic work using mitochondrial DNA confirms that the Galápagos shearwater is its closest relative.
This shearwater has a slender body, reaching about 36 cm in length with a wingspan of roughly 75 cm and a weight near 350 g. Its plumage is mostly dark—blackish-grey with a rusty-brown tint, slightly lighter underneath. There is a small patch of white under the chin, and pale edges appear on the upperwing coverts. Its feet are brown-grey, and its bill and eyes are dark. Males and females look the same, and young birds resemble adults after fledging. Nestlings are covered in dark grey down. It looks much like the sooty and short-tailed shearwaters but is smaller and has dark brown underwings. The tail is short and, in flight, usually tapers to a point, with the feet extending beyond the tail tip. It often flies in a relaxed, leisurely manner similar to petrels, which can lead to confusion with the very rare Fiji petrel. The two share similar shape and color, but the Christmas shearwater’s bulbous head and thin, long bill—typical of shearwaters—set it apart from the Fiji petrel’s slim head and thick bill.
The Christmas shearwater nests on remote islands across the Central Pacific, including the Northwestern Hawaiian Islands, Tuamotu, the Marshall Islands, Kiritimati (which gives the bird its name), and Sala-y-Gómez. It has disappeared from some islands, such as Wake Island. Outside the breeding season, it ranges widely across the Pacific, with records from the coast of Mexico and Guatemala in the east to the Bonin Islands in the west. It is rare farther south; for instance, it has been recorded off Fiji only twice, once in early to mid-May.
Like its relatives, it feeds at sea, mainly on squid and fish—especially flying fish and goatfish. It is highly pelagic and depends on predatory fish like tuna to drive prey to the surface. Besides the typical stiff-w
- Scientific name
- Puffinus nativitatis
- Length
- about 36 cm
- Wingspan
- around 75 cm
- Weight
- around 350 g
- Closest living relative
- Galápagos shearwater (Puffinus subalaris)
- Conservation status
- Least concern (IUCN)
Lore & Background
The Christmas shearwater was described and given its current binomial name by the American naturalist Thomas Hale Streets in 1877. A genetic analysis using mitochondrial DNA has shown that its closest living relative is the Galápagos shearwater. The species nests on remote islands of the Central Pacific, including the Northwestern Hawaiian Islands, Tuamotu, the Marshall Islands, Kiritimati, and Sala-y-Gómez, and has become locally extinct on a number of islands, including Wake Island.
It is a slender-bodied shearwater with dark plumage all over, generally blackish-grey with a rusty-brown tinge, slightly paler on the underside, and with some small edging of white under the chin and pale fringes to the upperwing coverts. Both sexes are alike, as are the young after fledging. Nestlings are covered in dark grey down feathers. The species closely resembles the sooty and short-tailed shearwaters, but has dark brown underwings and is smaller.
Like its relatives, it feeds at sea, predominantly on squid and fish, mostly flying fish and goatfish. It is highly pelagic and dependent on predatory fish such as tuna driving prey to the surface. It may use both the dramatic stiff-winged 'shearing' flight technique and the plesiomorphic flight technique of petrels, moving about with slow, leisurely wingbeats.
Reader's Guide
The Christmas shearwater is significant as a member of a very ancient lineage of small Puffinus species, offering insights into the evolutionary history of shearwaters. Its remote nesting habits and limited study at sea make it a poorly known species, highlighting the challenges of researching pelagic seabirds. The species' dependence on predatory fish like tuna for feeding underscores its role in the oceanic food web. Conservation concerns include threats from fishing, ingestion of plastic waste, and habitat degradation, as seen on Laysan Island where introduced rabbits degraded scrub cover and black rats took eggs and chicks. Despite these threats, its wide range and considerable numbers have led to its classification as a species of least concern by the IUCN. The Christmas shearwater's resemblance to the extremely rare Fiji petrel also makes it notable for birdwatchers and researchers attempting to distinguish between similar species at sea.
Did You Know?
- The Christmas shearwater was described and given its current binomial name by the American naturalist Thomas Hale Streets in 1877.
- Its only close living relative is the Galápagos shearwater (Puffinus subalaris), based on a genetic analysis using mitochondrial DNA.
- The species nests on remote islands of the Central Pacific, including Kiritimati (for which it is named), and has become locally extinct on Wake Island.
- On Laysan Island, introduced rabbits degraded the scrub cover, leaving adults, chicks and eggs vulnerable to overheating, and introduced black rats took eggs and chicks.
Frequently Asked Questions
What is the Christmas shearwater?
The Christmas shearwater (ʻaoʻū, Puffinus nativitatis) is a medium-sized tropical seabird native to the Central Pacific. At roughly 36 cm in length with a 75 cm wingspan and about 350 g in weight, it occupies a small, ancient branch of the Puffinus lineage.
Where does the Christmas shearwater nest?
This species breeds in very remote, hard-to-reach locations scattered across the tropical Central Pacific. Because those nesting sites are so isolated, the bird has been studied far less at sea than many other shearwaters.
What is the Christmas shearwater's closest living relative?
Mitochondrial DNA analysis has confirmed that the Galápagos shearwater (Puffinus subalaris) is its only close living relative. The two share an ancient branch within the small Puffinus group.
Who first described the Christmas shearwater?
American naturalist Thomas Hale Streets formally described the species and assigned it the name Puffinus nativitatis in 1877. That original description still underpins its current scientific identity.
Is the Christmas shearwater endangered?
The IUCN currently classifies the species as Least Concern, indicating no immediate population-level threat. However, its remote nesting habits and the scarcity of at-sea research make long-term monitoring difficult.
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