U.S. Fish and Wildlife Service officials have developed a plan that would allow expansion of the Hakalau Forest National Wildlife Refuge and its Kona Forest on Hawaii island by about 76 percent, or 29,973 acres.

The refuge encompasses 33,946 acres on the windward slope of Mauna Kea, with an additional 5,300 acres in the Kona forest on the leeward slope of Mauna Loa.

Refuge Manager Jim Kraus said the plan lays the groundwork for future acquisitions from "willing sellers."

"It does not imply we will get the lands," Kraus said.

The plan identifies land that would help to improve wildlife habitat for native plants and animals.

Kraus said the McCandless Ranch has indicated a willingness to sell some of its land, which could provide more habitat for the ‘alala, the endangered Hawaiian crow, or Corvus hawaiiensis.

Scores of ‘alala have been raised in captivity on Hawaii and Maui.

The wildlife refuge was established in 1985 to protect and manage endangered native forest birds and their rain forest habitat. It is among the most diverse in native forest birds and plants, including 27 listed under the federal Endangered Species Act.

The Kona forest area was added in 1997 to protect native plants and forest birds, including the ‘alala, and lava tube habitats.

The Hakalau refuge, including bogs, fern patches and scrub forest, receives an average of 250 inches of rain annually at the 4,000-foot level.

Kraus said the Hakalau area was the only wildlife refuge on Hawaii island where the population of forest birds is either stable or increasing.

"We feel pretty good about that," he said.

Native species commonly found in Hakalau include birds such as iiwi, apapane, amakihi, akiapolaau, elepaio and io, and the Hawaiian bat, opeapea.