Audubon's shearwater (Puffinus lherminieri) is a common tropical seabird in the petrel family. Sometimes known as the dusky-backed shearwater, the specific epithet honours the French naturalist Félix Louis L'Herminier. Certain populations are known variously as Baillon's shearwater, tropical shearwater, Bannerman's shearwater, Mascarene shearwater and Persian shearwater; some of these are considered distinct species by various authors. If they are all placed in P. lherminieri, the North Atlantic little shearwater (otherwise often separated as P. baroli) is generally included here too. Thus, these small shearwaters form a cryptic species complex. Description Audubon's shearwaters are on average in length—about half the size of the greater shearwater (Puffinus gravis)—and weigh 170 g. There is some variation between populations, and the normal size and weight range is and . The wingspan is , the tail is around long, the exposed culmen measures or slightly less, and the tarsus is around in length. In general appearance, it is a small shearwater, black above and white below and hard to distinguish from its relatives at first glance. The upperparts, rectrices and undertail coverts are blackish-brown, as are at least the distal undersides of the remiges, but sometimes the entire feathers. The rest of the underparts are white, as is the head below eye level. The iris is dark, the feet are dull pink with a black wash and black toenails, and the bill is grey, darker towards the tip, and with a pinkish hue. Males and females look alike. Immature birds do not have a distinct plumage, while the nestlings are covered with down feathers, grey above and whitish on the belly. It can be confused with the Manx shearwater (P. puffinus), which has white undertail coverts and in direct comparison a longer bill. Other similar-looking species are usually completely allopatric, though the largely subantarctic little shearwater (P. assimilis) may occasionally range into waters where P. lherminieri is normally found. It has more white on the face and underwing, a smaller bill and greyish-blue feet. Its twittering calls and mewing are often only heard at night in the breeding colonies. Range and ecology If not split into several species, Audubon's shearwater ranges across the Indian Ocean north to the Arabian Sea, throughout the north-west and central Pacific, in the Caribbean, and parts of the eastern Atlantic. It is a species of tropical waters; only some Atlantic populations and Bannerman's shearwater of the Ogasawara Islands occur farther