A medium-sized, all-black petrel with a dark-tipped yellowish bill. Breeds only on Great Barrier and Little Barrier Islands in New Zealand. Seen around Hauraki Gulf and pelagic waters near shelf break edges and seamounts around northern New Zealand. Migrates to coastal South America during nonbreeding period. Similar to White-chinned Petrel and Westland Petrel, but is smaller, with a darker-tipped, less robust bill; lacks the small white patch under the chin; and is found in northern New Zealand waters as opposed to the Cook Strait and the South Island. Overlaps in range with Flesh-footed Shearwater, which is smaller, has pink-colored legs, and shows a pinkish bill with a black tip.