Audubon's shearwater 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
Hutton's shearwater a white underbelly and brown collar, dark borders to the underwing, dark grey bill, and pinkish dark-webbed feet; it can be distinguished from fluttering shearwater by its dark grey "armpits". At a breeding colony it has a loud cackling call. Hutton's shearwater feeds in the open ocean largely on small fish and krill, diving up to 20 m. "Puffinus huttoni" have long bills, which are adapted to catch prey more or less underwater by plunging from a few meters above the surface or by paddling slowly forwards searching with their head submerged, then diving using partly opened wings for propulsion.