HILO, Hawai'i — The Hawaiian hawk population on the Big Island has recovered, stabilized and expanded to more than half of the island, and the predatory bird no longer needs to be included among those protected by the Endangered Species Act, according to the U.S. Fish and Wildlife Service.

Fish and Wildlife yesterday proposed a rule change that would remove the hawk or 'io from the endangered species list, but said the hawk would continue to be protected under the Migratory Bird Treaty Act, a federal law that prohibits killing, selling or otherwise harming migratory birds and their nests and eggs. The hawk would also continue to be protected under state law.

The hawk population was believed to have declined to just a few hundred when it was protected under the Endangered Species Preservation Act in 1967, but the population has grown to about 3,000 over the past 40 years and has stabilized, according to Fish and Wildlife.

The small hawk is endemic to the Hawaiian Islands and is the only member of the hawk family that nests here. In Hawaiian culture the 'io is believed to be an 'aumakua, a family or personal god in the shape of an animal. The hawks are also considered a symbol of Hawaiian royalty.

The hawks mate for life and defend their territories year-round, and are only known to breed on the Big Island. However, hawks have been seen at least eight times on Kaua'i, O'ahu and Maui since 1978.

The 'io was listed as endangered based on its limited range on the Big Island, its small population and the loss of native forest habitat from agriculture, logging and development.

The hawk was originally believed to live only in undisturbed native habitat, but scientists later learned it can also survive in non-native forests, pastures and agricultural lands at high and low elevations, preying on native and non-native species such as rodents and large insects.

The Fish and Wildlife Service proposed downgrading the hawk from endangered to threatened status in 1993, but that stirred public concern, and the service never made the change.

In 1997 the National Wilderness Institute of Washington, D.C., proposed delisting the hawk, and in 2001 an 'io Recovery Working Group also recommended delisting, according to an announcement yesterday of the proposed change by Fish and Wildlife.

The plan to delist the hawk did raise concern for Marjorie Ziegler, executive director of the Conservation Council for Hawai'i, who said any species unique to Hawai'i is at risk to some degree.

"Don't take it off the list," she said. "Maybe downlisting it to threatened species might be a good first step as opposed to just taking it off the list completely."

David Henkin, staff attorney for Earthjustice, said another concern is the potential for some catastrophe that would devastate the remaining hawk population, such as a hurricane or avian disease outbreak.

"All these things could really take their toll on a single island species," he said. "Regardless of the population stability, we're still only talking thousands of birds on a single island. Endemics are always of concern."

Paul Conry, administrator of the state Department of Land and Natural Resources Division of Forestry and Wildlife, said delisting the hawk is probably appropriate now that the population has been stable for 10 to 20 years, and has met the scientific targets in its recovery plan.

The protected habitat for the hawk in conservation management on the Big Island now includes more than 500,000 acres of state land alone, and more than 1 million acres in watershed partnerships that will have increasing conservation management in the future, he said.

"I think the outlook for a secure habitat that is protected from development is real good," he said.

The Endangered Species Act requires that if the hawk is de-listed, its population must be monitored for at least five years, so if the population does decline later for any reason, "you can always go back in and put the protections of the act back in place," Conry said.