The American Bird Conservancy and a noted Hawai'i scientist have submitted a petition to the U.S. Fish and Wildlife service on behalf of the akekee and the akikiki, both of which live in the higher elevations of the Alakai Wilderness.

Populations of the two birds have shrunk to all-time lows this year based on surveys conducted in April and May, according to the American Bird Conservancy.

"The akikiki and the akekee are seriously in trouble," said George Fenwick, president of the American Bird Conservancy. "The strongest available measures such as captive breeding, fencing out and removal of invasive species ... are all necessary to prevent these species from going extinct."

Their habitats are threatened by alien plants, feral pigs, diseases and inclement weather, the group said.

The Fish and Wildlife Service has 90 days to decide whether to conduct a yearlong status review of the birds, which is required before adding them to the endangered species list, said agency spokesman Ken Foote.

"People's observations were that the akekee has disappeared from several areas where it had been easy to find in the past," said Erik VanderWerf, a scientist for the Pacific Rim Conservation, a consulting group. "And the akikiki have been definitely in trouble and a candidate for listing since 1994."

The akikiki are small honeycreepers, dark above and light below, with a pink bill. Their current population could be as low as 782, down from about 7,000 birds in 1970, according to the American Bird Conservancy.

The akekee also are honeycreepers, yellow and green with short blue bills and long notched tails. Their population is estimated to be as low as 2,506 compared with about 8,000 in 2000, the group said.

Both of their habitats have gotten smaller in recent years.

The birds need more research on what's causing them to die off, VanderWerf said.

"We don't really know what the causes are," he said, although mosquito-borne diseases like malaria and avian pox are suspected. "The listing of the akikiki and akekee to me is a slam dunk," he said.

Hawaii leads the nation in the number of endangered and threatened species with 329.

There were at least 71 endemic bird species on Hawaii in 1778, but 26 of those have since gone extinct and 32 more are now listed as endangered or threatened, the conservancy said.