Cook's petrel is endemic to the New Zealand archipelago (del Hoyo, et al. 1992), which comprises two main islands, the North and South Islands, and numerous smaller islands. The total land area of the archipelago covers 103,700 square miles (268,680 km\2\, Wikipedia 2007i). Historically, Cook's petrels were harvested in large numbers as a food source by native Moriori (Oliver 1955). Although the Cook's petrel was once considered a dominant species on these islands, the species' breeding and nesting activities are now restricted to islands at the northern and southern limits of its former breeding range, including Great Barrier (Aotea), Little Barrier (Hauturu), and Codfish (Whenua Hou) Islands (del Hoyo, et al. 1992). The species' diet consists primarily of cephalopods, fish, crustaceans, and bioluminescent tunicates that can be hunted at night (Imber 1996). The IUCN classifies this species as ``Endangered'' (BirdLife International 2006b). Although the population on Little Barrier Island was thought to be about 50,000 pairs (BirdLife International 2007b), using GIS (Geographic Information System) technology, Rayner, et al. (2007b) determined that the population is around 286,000 pairs. In 2006, the Great Barrier Island population was considered to be in danger of extirpation because only four nest burrows had been located in recent years, and it was estimated that fewer than 20 pairs continued to breed on the island. However, the populations on Little Barrier and Codfish islands are likely to be increasing (BirdLife International 2007b).