By Jan TenBruggencate
Advertiser Columnist

They are called Hawai'i forest birds, largely because most surviving Hawaiian birds are found in high-elevation forests of the Islands, but there is little question these creatures once flitted from the uplands to the beaches.

Their fossilized bones have been found in coastal sand dunes, and there are even human recollections of "forest" birds living at low elevations.

The red and black honeycreeper known as the 'apapane is a classic upland forest bird. It's an active nectar eater, still fairly common, but it's mainly restricted to the highlands, where it flits among the 'ohi'a trees and sips at the flowers of alien plants like the banana poka.

The Laysan 'apapane was similar but with a little more of an orange than red tint to its plumage. This 'apapane lived at sea level on Laysan Island in the Northwestern Hawaiian Islands until 1923, when the devastation of the island by rabbits did it in.

Folks figured the Hawai'i state bird, the nene, had evolved away from the low lands to the volcanic mountaintops. That was until folks noticed that they do fine at low elevations as well, if they can be kept safe from dogs, cats, mongooses and rats.

Flocks of nene now fly over parts of Kaua'i, which is mongoose-free. Occasionally a pack of dogs will wipe out a cluster of nests, but the Kaua'i nene seem to be holding on.

It is clear that most of Hawai'i's surviving native birds are found in the high forest because they have been wiped out everywhere else by competition, loss of habitat, predators and alien bird diseases like pox and malaria.

Recently, a population of Big Island 'amakihi — a yellow to olive-colored Hawaiian honeycreeper with a short bill — was found in a lowland coastal forest on the southeast side of Kilauea. Researchers were fascinated, and a team led by Allison Klein of the U.S. Geological Survey's Pacific Island Ecosystems Research Center reported initial studies on the birds in the latest issue of 'Elepaio, the journal of the Hawai'i Audubon Society.

They are living in a forest mainly of small 'ohi'a trees growing on lava two centuries old. One interesting feature is that lowland 'amakihi build thinner nests than their upland kin — probably because in warmer weather the eggs don't require the additional insulation.

The sad news: Predators killed every single one of the eggs and chicks in six nests the scientists watched early in 2003. The team concluded predators may be the biggest factor keeping the birds from thriving at low elevations.

Jan TenBruggencate is The Advertiser's Kaua'i Bureau Chief and its science and environment writer. Reach him at at jant@honoluluadvertiser.com or (808) 245-3074.