Australasian Gannet (Morus serrator). This sub-species has more black on the primaries and tail than its North Atlantic cousin.
All the nesting images were taken at Muriwai - one of only three places where they nest on the mainland in New Zealand. At the time of my visit (many years ago) most nests were on the rocky outcrop and they were beginning to colonize the shore in similar numbers. I believe there are many more there now in the "overflow nesting area". Maybe I'll get back there one day? In some of the images you can also see Terns nesting or flying - White-fronted Terns?