We have some early sketches by Jeanine Higa, who is working with fellow animator Kayla Abalos on the section about the Kaua‘i ‘o‘o's extinction, whose distinctive song was last heard in 1987. These birds were famous for their elaborate and beautiful mating calls sung by both the male and female. You can hear the heartbreaking last recorded ‘o‘o song here.
Their distinctive yellow feathers that would surround their legs were carefully plucked out by native Hawaiians who used them on royal clothing such as the ʻAhu ʻula, pictured below.
The different genuses of ‘o‘o were once found on O‘ahu, Kaua‘i, Molokai, and Hawai‘i but are now all extinct. According to the U.S. Fish and Wildlife Services, "The exact reasons for their decline are not known, but avian diseases and land clearing are believed to be major factors."