Creature Feature #536: ʻōʻō

The Hawaiian ʻōʻō was a beautiful nectivorous songbird, endemic to the Hawaiian islands. There were four distinct species, occupying separate islands. The largest measured around 30 cm from head to tail. He was generally considered to be related to the Australian honey-eaters and shared a similar diet - drinking the nectar from flowers. Genetic research has since shown them to be distinctly different, and any similiarities a result of convergent evolution, where unrelated species develop similar traits to fill similar niches.

 The arrival of humans on the islands marked the beginning of the end for the ʻōʻō. Birds on Oahu and Hawai'i were hunting extensively for their yellow feathers, which were worn by nobility. Deforestation claimed their land, rats claimed their nestlings, and like many Hawaiian birds, they proved vulnerable to the introduction of bird malaria. The first to become extinct was the Oahu ʻōʻō in 1837, the Bishops ʻōʻō of Molokai following in 1904 and the Hawaiian ʻōʻō hanging on until the last confirmed sighting in 1937. The smallest, the Kaua'i ʻōʻō survived a little longer - mongoose never made it to that island - being declared extinct then rediscovered on several occasions, but surveys in 1987 found no evidence of their continued existence.

The ʻōʻō, like the huia and oh-so-many beautiful, unique birds, is an example how isolated populations can be extremely vulnerable to outside pressures, especially when they have evolved without the addition of natural land predators. Neither New Zealand nor Hawaii had any mammalian predators until humans came and brought with them the rats and mice, mongoose (Hawaii) and mustelids (New Zealand).