The native koa and ohia trees in the Kau Forest Reserve reach 100 feet into the sky, providing a haven for critically endangered Hawaii birds to nest and forage. But feral pigs, cattle and sheep are tearing up the ground, making it hard for new trees to grow.

Luckily for the birds, there's help on the way. This year, in response to a report highlighting the perilous state of Hawaii's native avian species, the federal government is spending $2 million to restore the forest on the volcanic slopes of Mauna Loa.

“;These animals are part of the natural heritage and the cultural heritage of the islands,”; said Scott Fretz, wildlife program manager for the state Department of Land and Natural Resources.

Hawaii once had 113 bird species found nowhere else in the world. But non-native animals—like pigs and cows—and plants destroyed vast areas of their habitat. Invasive species like mongoose have eaten the birds and their eggs, while new diseases carried by mosquitoes, like malaria, have killed many.

Today, 71 of those bird species are extinct. An additional 31 are listed as endangered or threatened—including some species not seen in decades that might already be extinct. The state has the dubious distinction of having one-third of the nation's endangered birds.

The U.S. Fish and Wildlife Service had only $6 million last year to spend on all 400 endangered species in the Pacific Islands region, which includes Hawaii, Guam and American Samoa. So the addition of $2 million just for the birds is expected to provide a significant jolt.

The money comes in response to a report commissioned by then-President George W. Bush in 2007. Released in March 2009, the study pointed out Hawaii accounted for 44 percent of the nation's federally listed bird species but only received 4 percent of all federal and state funding.

The birds set to benefit from the multimillion-dollar influx are among those given top priority by officials and conservationists.

One, the alala or Hawaiian crow, is already extinct in the wild. There are only 67 in captivity, some of which the state and federal governments hope to release into the Kau forest once the habitat is ready.

The yellow-olive green akiapolaau, whose distinctive curved bill allows it to snatch insect larvae from tree bark, numbers only about 1,900.

Both are found only on Hawaii island, like the other endangered birds expected to enjoy the rejuvenated forest, which include the Hawaii creeper, the Hawaii akepa and the io, or Hawaiian hawk.

Fretz said Kau's forest is majestic and expansive but also deteriorating. “;It's not abrupt—it's not like you went through there with a bulldozer and mowed everything down. It's more of slowly not allowing the forest to regenerate itself,”; Fretz said.

The pigs also harm the birds by digging mud wallows while burrowing for food. Water collects in these holes, offering malaria-carrying mosquitoes a breeding ground. Malaria is now one the biggest threats to Hawaii's forest birds.

Federal and state officials are working on the project now and plan to seek ideas and opinions from the community.

They hope to remove the feral pigs, cattle and sheep, likely with a public hunting program, though staff may have to go after individuals in more remote areas.

They expect to set traps for rats, cats and mongoose that prey on the birds. One possibility might be to put up fences around parts of the forest to keep out animals once they are removed.

Officials already have plans to put up a similar fence around parts of Mauna Kea volcano to protect the endangered palila, a bird whose numbers have precipitously dropped from 6,600 in 2002 to about 2,500 in recent years.

The fences there would keep out grazing feral sheep that ruin the native mamane trees the songbird relies on for food.