Hawaiʻi creeper is able to climb up and down trees. It uses its short, sharp beak to probe bark for insects residing underneath. If available, it will sip nectar from koa ("Acacia koa") or ōhia lehua ("Metrosideros polymorpha"). The breeding season of the Hawaii creeper lasts from April to July, during which female birds lay one to three eggs. Nests are hidden in a tree cavity or built on a high branch in either a koa ("Acacia koa") or a ōhia lehua ("Metrosideros polymorpha"). Eggs hatch after around thirteen days. The Hawaii creeper was put on the endangered species list in 1975;
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