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;
Leaf nearly petiolate or have an extremely short petiole and may appear to be sessile. In clasping or decurrent leaves, the blade partially surrounds the stem. When the leaf base completely surrounds the stem, the leaves are said to be perfoliate, such as in "Eupatorium perfoliatum". In peltate leaves, the petiole attaches to the blade inside the blade margin. In some "Acacia" species, such as the koa tree ("Acacia koa"), the petioles are expanded or broadened and function like leaf blades; these are called phyllodes. There may or may not be normal pinnate leaves at the tip of the phyllode. A