$Pterodroma [cookii] pycrofti Sibley & Monroe,1990,Distribution and Taxonomy of Birds of the World,p.322.
Marine & pelagic,occurring in cold waters of subantarctic and Antarctic zones.Breeds on oceanic islands,occupying coastal slopes often with tussock grass.
"Starts Sept" (HBW,1,p.248)
Adults perhaps mainly sedentary. They visit colonies intermittently during winter and probably remain in surrounding area.Young birds more dispersive,occurring north to 20°S off Peru,and to 40°S in Atlantic and Indian Oceans;also south to zone of pack ice.