Oʻahu nukupuʻu bill to pluck insects found underneath tree bark, the Oahu nukupuu fed on insects on flowering trees such as the koa ("Acacia koa") and ohia ("Metrosideros polymorpha"). These trees attract a large amount of insects due to their nectar-filled flowers. The Oahu nukupuu fed on koa in high elevation forests and fed on ohia in low elevations. The species was believed to have vanished as the spread of disease occurred, killing off nukupuu populations across the islands. In order to control the rat population in the sugar cane fields, mongooses were introduced to Hawaii and were suspected to be predators
Koa Kannon the Soto school. General Iwane Matsui who commanded the Shanghai Expeditionary Force at the outbreak of the Second Sino-Japanese War built the Koa Kannon statue after retiring from the service in 1940 to honor the officers and men of both China and Japan who fell in battle in the name of consecrating equally both friend and enemy. The statue was made using clay from battlefields, including from the vicinity of Nanjing where Matsui served. On 24 February 1940 the consecration ceremony was performed in the presence of Tessui Oshima, a high-ranking Jodo Buddhist monk from Zojo-ji, and other distinguished figures.