Acacia koa Acacia koa Acacia koa is a species of flowering tree in the pea family, Fabaceae. It is endemic to the Hawaiian Islands, where it is the second most common tree. The highest populations are on Hawaii, Maui and Oahu. Its name in the Hawaiian language, koa, also means brave, bold, fearless, or warrior. Koa is a large tree, typically attaining a height of and a spread of . In deep volcanic ash, a koa tree can reach a height of , a circumference of , and a spread of . It is one of the fastest-growing Hawaiian trees, capable of
ʻAnianiau Its call is a pair of notes, "tew-weet", while its song is a trill of "wee-see, wee-see, wee-see". Anianiau are found in mesic and wet forests at elevations above . The highest densities occur above . Dominant tree species in its habitat include koa ("Acacia koa"), ōhia lehua ("Metrosideros polymorpha"), ōlapa ("Cheirodendron trigynum"), and lapalapa ("C. platyphyllum"). The anianiau mainly feeds on nectar from the flowers of plants such as ōhia lehua ("Metrosideros polymorpha"), ōhelo ("Vaccinium" spp.), and alani ("Melicope" spp.). It will also take arthropods from trees, shrubs, or vines. The anianiau breeding season ranges from February to June.