A small shearwater, black above and white below with a long tail and long, thin bill. The white on the belly extends up on to the flanks, forming a distinctive white spot behind each wing. Nests primarily on Kauai, with smaller numbers on other islands. Regularly observed offshore from boats, especially around Kauai, but sometimes near other islands. The voice, usually heard only at breeding colonies, is similar to the braying of a small donkey.