Acacia heterophylla 1.4 million years ago. "A. heterophylla" sequences nest within those of the more diverse "A. koa", making the latter species paraphyletic. Both species are descended from an ancestral species in Australia, presumably their sister species, "Acacia melanoxylon"; the means of dispersal to Hawaii and then to Réunion (the latter trip a distance of 18,000 km) is thought to have been seed-carrying by birds such as petrels (the seeds of these species are not adapted for prolonged immersion in seawater). Both species also have very similar ecological niches, which differ from that of "A. melanoxylon". Acacia heterophylla Acacia heterophylla, the highland
Lesser koa finch was smaller than the other scientifically described koa finches, measuring on average only five inches in length. Its life cycle and feeding habits apparently centered around the koa plant from which it got nectar and fruit (and for which it was named). The koa also provided refuge for small flocks of the finch as it avoided people and the noon high sun. It was seen congregating with its larger relative, the greater koa-finch. Several specimens were collected and sent to London, Cambridge, New York, Philadelphia, and Berlin. The bird appeared to have always had a small population. When people brought