The Christmas Shearwater is an all-dark and small shearwater of the Tropical Pacific. It does not breed near the Americas, but in its non-breeding wandering it may come into pelagic waters of Central America and perhaps northern South America. While the outward appearance of this shearwater may suggest relationship to Sooty (Puffinus griseus) or Short-tailed shearwaters (Puffinus tenuirostris), molecular data actually suggests a close relationship to the Galapagos Shearwater (Puffinus subalaris) a small shearwater with white underparts. Christmas Shearwaters are named for the type locality, Christmas Island (Kiritimati Island). This small shearwater may be separated from Sooty and Short-tailed shearwaters by the noticeably smaller size, also by the rather rounded wings and preference for warmer water.