Primitive koa finch Primitive koa finch The primitive koa finch ("Rhodacanthis litotes") is a species of Hawaiian honeycreeper. It was endemic to Hawaii. Of the four species in the genus "Rhodacanthis", it and the scissor-billed koa finch became extinct before the arrival of the first Europeans to Hawaii in 1778. It is known as the ancestor of all koa finches. An adult primitive koa finch was slender and had a total length of about . There was probably a small distinct difference between the sexes. Based on fossils, it is known that the adult primitive koa finch had a slightly curved, thick bill.
Acacia koa there are few koa remaining which are both large and straight enough to do so today. In areas where cattle are present, koa regeneration is almost completely suppressed. However, if the cattle are removed, koa are among the few native Hawaiian plants able to germinate in grassland, and can be instrumental in restoring native forest. It is often possible to begin reforestation in a pasture by disk harrowing the soil, as this scarifies seeds in the soil and encourages large numbers of koa to germinate. Experiments at the Hakalau Forest National Wildlife Refuge have shown that ōhia lehua ("Metrosideros polymorpha")