Christmas Shearwater, Puffinus nativitatis
The Christmas Shearwater, (Puffinus nativitatis), is a species of bird found throughout the tropical Central Pacific islands, including the Hawaiian Islands, Tuamotu, the Marshall Islands, Kiritimati and Sala-y-Gómez. It has become locally extinct on a number of islands within its range. During the non-breeding seasons it extends across the Pacific, with some records reaching Mexico and Guatemala in the east, and Bonin Islands in the west. It is a rare vagrant further south, being recorded off Fiji only twice.
It is a member of a very ancient lineage of the small Puffinus species. Its only close living relative is the Galapagos Shearwater. The Christmas Shearwater can often be mistaken for a petrel when in flight.
This is a slender-bodied bird, about 14 inches in length, with a wingspan of nearly 30 inches. It weighs about 12.3 ounces. It has dark plumage all over, generally blackish-gray with a rusty-brown tinge. The underside is slightly paler than above. It also has some small edging of white under the chin and pale fringes to the upperwing coverts. Its feet are brown-gray, the bill and eyes are dark. Sexes are similar, as are the young after fledging. Nestlings are covered in dark gray down feathers.
Like its relatives, the Christmas Shearwater feeds at sea, predominantly on squid and fish (mostly flying fish and goatfish). It is highly pelagic (living at sea) and is dependent on predatory fish such as tuna driving potential prey species to the surface. Along with its typical stiff-winged “shearing” flight technique that is seen in other shearwaters, the Christmas Shearwater may also use slow, leisurely wing beats like that of the petrel.
This bird nests on sandy islands with good cover, usually provided by naupakas shrub or rock outcroppings. The female lays a single white egg. The timing of the laying varies from island to island, and on some islands breeding takes place throughout the year. The egg is incubated for about 50 days. Fledging varies depending on the season, ranging from 60 to 100 days.
The Christmas Shearwater is threatened worldwide by fishing, ingestion of plastic waste, and habitat degradation. On Laysan Island introduced rabbits degraded scrub cover, leaving adult shearwaters, chicks and eggs vulnerable to overheating, and introduced black rats took eggs and chicks. But because of its wide range and considerable numbers, this species is considered a Species of Least Concern by the IUCN.