Buller's shearwater (Puffinus bulleri)
Breeds only on the Poor Knights Islands, just to the north of the Hauraki Gulf. Population has increased dramatically in the last two decades and is estimated now at 2.5 million birds. Only one hundred pairs bred on the island in 1938, but since the removal of pigs from the island, which frequently trampled the birds burrows, numbers of Buller’s shearwaters have increased dramatically. Like the flesh-footed shearwater, Buller’s shearwaters migrate after breeding in New Zealand to the waters of the North Pacific, especially off Japan and Alaska. Buller’s shearwaters feed on small krill and jellyfish. In recent years they have started to feed on food scraps thrown overboard from fishing boats. Buller’s shearwaters have a distinctive series of rapid wing beats followed by a long glide. Flocks of over 10,000 birds have been seen off the Northland Coast.
Buller’s shearwaters are seen off the Kaikoura Coast from October to May. During the height of summer, flocks of over a hundred birds can be seen. Buller’s shearwaters frequently feed with other species of shearwaters such as sooty, flesh-footed and Hutton's shearwaters, which form large flocks flying in circles over schools of baitfish