(one time in early to mid-May). Behaviour Diet and feeding Like its relatives it feeds at sea, predominantly on squid, and fish, mostly flying fish (Exocoetidae) and goatfish (Mullidae). It is highly pelagic and is dependent on predatory fish such as tuna driving prey to the surface. As mentioned above, it does not only have the dramatic stiff-winged "shearing" (dynamic soaring) flight technique which gave the shearwaters their common name. In addition to it, it may use the plesiomorphic flight technique of petrels and similar Procellariidae, moving about with slow, leisurely wingbeats. Breeding The Christmas shearwater nests on sandy islands with good cover. It nests on the surface, underneath dense cover (such as naupakas, Scaevola), or under rock outcroppings. It lays one white egg, the timing of laying varying from island to island, on some islands breeding throughout the year. The egg is incubated for around 50 days. The time taken to fledge varies depending on the season, ranging from 60 to 100 days. Status and conservation Although few specific studies have been conducted on the Christmas shearwaters, petrels and shearwaters are threatened worldwide by fishing, ingestion of plastic waste, and habitat degradation. For example, on Laysan Island the introduced rabbits degraded the scrub cover, leaving adults, chicks and eggs vulnerable to overheating, and introduced black rats took eggs and chicks. In 1985, the population on Sala-y-Gómez, a nature sanctuary, was estimated at 5,000. With its wide range and considerable numbers, the Christmas shearwater is considered a species of least concern by the IUCN. Footnotes References Austin, Jeremy J. (1996): Molecular Phylogenetics of Puffinus Shearwaters: Preliminary Evidence from Mitochondrial Cytochrome b Gene Sequences. Mol. Phylogenet. Evol. 6(1): 77–88. (HTML abstract) Seto, N.W.H. (2001): Christmas Shearwater (Puffinus nativitatis). In: Poole, A. & Gill, F. (eds.): The Birds of North America 561. Academy of Natural Sciences, Philadelphia, PA & American Ornithologists' Union, Washington, D.C. (requires subscription) Shirihai, Hadoram; Pym, Tony; Kretzschmar, Jörg; Moce, Kolinio; Taukei, Amania & Watling, Dick (2009): First observations of Fiji Petrel Pseudobulweria macgillivrayi at sea: off Gau Island, Fiji, in May 2009. Bull. B.O.C. 129(3): 129–148. PDF fulltext Christmas shearwater Christmas shearwater Birds of the Pacific Ocean Christmas shearwater Christmas shearwater