The birds have been found to be nesting in the upper watershed areas of Lana'i where Castle and Cooke has been implementing a watershed protection program.

The discovery of the population was made last year and DLNR has deployed a team of biologists to the island to learn more about the birds and their conservation needs.

"Castle and Cooke's work to protect the watershed is a great benefit not just for the water resources it provides to the community but clearly for Hawaiian wildlife as well," said Allan Smith, DLNR interim chairperson. "We're pleased to partner with Castle and Cooke and are working with them to develop new phases of the work that will protect larger areas of the watershed."

"We appreciate this collaboration between Castle and Cooke, and DLNR, U.S. Fish and Wildlife Service, and University of Hawai'i, that is allowing biologists to conduct surveys across the watershed to determine the extent of the birds' breeding colony," said Smith. "They have also begun to control introduced predators that could kill the young nestlings in their burrows before they are able to fly," he said.

"The Lana'i Hale watershed had not been surveyed for petrels since the 1980s so we didn't know what to expect," Scott Fretz, DLNR wildlife program manager, said. "We assumed there would be few, if any, birds remaining on Lana'i, but once we started the surveys we immediately realized that we had found something special."

"We don't yet know the total number of birds on Lana'i but there appear to be hundreds, if not more, which would make this one of the biggest populations known in the state," Fretz said. "This discovery indicates that the population there has grown significantly in the last 20 years."

'Ua'u spend most of their lives at sea, returning to land only part of the year to breed and fledge their young. Even then, the birds only return to the upland nesting areas after dark and in the morning they fly to sea to feed before dawn. They are an elusive species to study and biologists employ special methods such as thermal imagers, night vision technology, and marine radar to gather the information needed to develop conservation programs to protect the birds.

'Ua'u were once common throughout the Hawaiian Islands but were decimated by the introduction of predators such as cats, rats, and barn owls, and loss of native habitats that the birds depend on for nesting.

The petrels were common on Lana'i in historical times but had all but disappeared by the 1980s because of habitat destruction and predators.