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 one urn was secretly collected up by a group including Miyoshi Tobita, the manager of Kuboyama Crematorium, and Shohei Sanmonji, defense counsel to Kuniaki Koiso, and on 3 May 1949 this urn was carried to the Koa Kannon temple due to its links with Matsui. Right away the head priest Master Ninrei Itami intuitively understood that these were the ashes of the seven war criminals and hid them until he thought the time was right. Finally on 19 April 1959 the stone monument of the seven warriors was erected, with the inscription written personally by former prime minister Shigeru Yoshida,