Barolo shearwater a distinct species (Sangster et al. 2005), as has "Clements Checklist". The American Ornithologists' Union followed in 2013. Features that distinguish the Barolo shearwater from the Manx shearwater and other North Atlantic "Puffinus" species include the pale face, silvery panel in the upperwings, shorter more rounded wings, and blue feet. As well as the pale face with the darkly contrasting eye. The Baraolo shearwater occurs in the Macaronesian Islands and breeds on the Azores, Desertas, Selvagens and Canary islands. The largest colony, of 1400 pairs, occurs on the Selvagen Islands. The Barolo shearwater feeds in the upper 15m of the
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.