A court filing yesterday accused the state Department of Land and Natural Resources of failing to fully comply with court orders to protect the critically endangered palila bird on the Big Island.

The DLNR had no immediate response to the filing by Earthjustice.

The environmental law firm, which is representing the Hawaii Audubon Society, the National Audubon Society and the Hawaii chapter of the Sierra Club, said three federal court orders dating to 1979 require the state to keep the bird's critical habitat atop Mauna Kea clear of feral goats and sheep and mouflon sheep.

Last week, a federal report said the population of the palila, a yellow-crowned songbird, plunged by more than 60 percent from 6,600 in 2002 to 2,200 in 2008.

"The state is not taking effective action to keep the sheep out of the palila's critical habitat, and the palila population is suffering for it," said John Harrison, president of the Hawaii Audubon Society.

"Palila are on a crash-course toward extinction in large part because browsing animals are allowed to continue to destroy their only habitat," he said.

Sheep are gaining access to the palila's forest habitat from surrounding lands because the state has allowed a 55-mile fence surrounding the forest to fall into disrepair, Earthjustice said.

"Along with increasing the effectiveness of sheep hunts, the state must replace the 70-year-old fence to keep the sheep out," Earthjustice attorney Koalani Kaulukukui said. "The state has known since 1979 that it needs an adequate fence to comply with the court's orders but remains in violation of the law."

The environmental groups asked the court to order the state to construct a mouflon-proof fence around the palila's critical habitat by no later than June 1, 2011.

Holly Freifeld, a vertebrate recovery coordinator with the U.S. Fish and Wildlife Service in Honolulu, said last week that the agency planned to fence off an area on Mauna Kea, and remove sheep from the fenced area, to give the palila an environment where it can flourish.

Palila nest in mamane trees, and mamane seed pods are their preferred food.

Browsing sheep eat away the lower branches of mature mamane trees, removing some of the palila's food, and destroy young mamane trees, Earthjustice said. The forest is disappearing because young trees aren't replacing older trees as they die off, it said.