Two subspecies of Cape Petrel occur in New Zealand. The Snares Cape Petrel (Daption capense australe) has darker upperwings and is endemic, breeding in NZ and the Sub-Antarctic islands; the Antarctic Cape Petrel (Daption capense capense) is a common migrant to NZ waters in winter and spring and breeds in the Antarctic. This subspecies has white feathers across the whole of the upperwings.
The amount of white does vary with feather wear and distinguishing the two subspecies is not necessarily possible. Most of the birds shown in these images have more of the Snares Petrel characteristics.