Greater koa finch and maximum growth of a single species of koa finch. The greater koa finch was a granivore, preferring the pods and seeds of koa ("Acacia koa"). It was also observed eating caterpillars and aalii ("Dodonaea viscosa") seeds. The last confirmed sighting was in 1896, although there were sporadic later reports. Like its close relative the lesser koa finch, this bird lived in small stretches of mesic forest on the Big Island of Hawaii. These forests were dominated by its preferred food source, koa ("Acacia koa"), and were logged and replaced with pasture beginning in 1850. Grazing by cattle inhibited the
Koa wilt mortality rate over several years due to Koa wilt. It is also a legume, giving it the ability to form symbiosis with nitrogen fixing bacteria, which has led to efforts to use koa in agroecological systems with crops such as coffee and cacao. Ecologically, koa is an important species because it is one of the few native trees that remains dominant in alien mixed forests on the Hawaiian Islands. Invasive species make up the majority of the State's current plant population. Koa trees also are important because provide a habitat for many native bird species. Historically, there were once two