Small seabird with a relatively long, forked tail. Unique among storm-petrels with entirely silvery-gray plumage. Aside from overall plumage color, look for contrasting dark underwings, dark mask around eye, and dark band on upperwing bordered by white. Breeds on offshore islands. Fairly common over cool water, often not far from shore. Found singly or in large flocks, often mixed with other storm-petrels.