Hawaiian petrel Hawaiian petrel The Hawaiian petrel or uau ("Pterodroma sandwichensis") is a large, dark grey-brown and white petrel that is endemic to Hawaii. The Hawaiian petrel was formerly found on all the main Hawaiian Islands except Niihau, but today it is mostly restricted to Haleakalā crater on Maui; smaller populations exist on Mauna Loa on the island of Hawaii, Waimea Canyon on the island of Kauai, Lānaihale on Lānai, and possibly Molokai. It is also reportedly seen on the Galapagos Islands. Their diet consists of 50–75% squid, and smaller percentages of fish and crustaceans. The birds nest in burrows or rock
Endemism in the Hawaiian Islands was critical to the formulation of his theory of evolution is far exceeded in the more isolated Hawaiian Islands. The relatively short time that the existing main islands of the archipelago have been above the surface of the ocean (less than 10 million years) is only a fraction of time span over which biological colonization and evolution have occurred in the archipelago. High, volcanic islands have existed in the Pacific far longer, extending in a chain to the northwest; these once mountainous islands are now reduced to submerged banks and coral atolls. Midway Atoll, for example, formed as a volcanic