Kaua'i 'O'o; O'ahu 'O'o; Hawai'i 'O'o; Bishop's 'O'o; Kioea

The Hawai'i 'O'o was the first Hawaiian honeyeater discovered by westerners, described from a specimen obtained in 1779 during Captain James Cook's third voyage; the other 4 species were not known to the scientific community until the mid- to late 1800's. The O'ahu and Hawai'i 'o'o and the Kioea are now definitely extinct, and the Kaua'i and Bishop's 'o'o are probably extinct.