ʻIʻiwi (Vestiaria coccinea)

By Zoe Statman-Weil, Pollinator Partnership

The Fight for Hawaii’s Beloved Crimson Bird

If you are lucky enough to have visited the Hawaiian Islands, then you may have glimpsed a beautiful fire-red finch with black wings and a decurved salmon-colored beak. This bird (Vestiaria coccinea) is called the ʻIʻiwi or the Scarlet Hawaiian honeycreeper. There is currently a struggle for its protection. The ʻIʻiwi is relatively abundant, but its population is showing signs of decline in some areas. This, combined with a decreasing range, has inspired scientists to advocate for its formal protection.

The ʻIʻiwi is most common in mesic and wet forests on the islands of Hawaiʻi, Maui and Kauaʻi. Although it used to be present on all of the Hawaiian islands, it is now extinct on Lanaʻi and less than 50 birds can be found on Oʻahu and Molokaʻi. This significant drop in numbers prompts conservation biologists to ask the question: Why is the ʻIʻiwi population declining? There are a few factors involved. Increased agricultural and urban development in Hawaii has resulted in decreased natural ʻIʻiwi habitat, and the introduction of new predators, such as pigs, cattle, cats and rats, also impacts survival rates.

Even more detrimental to the ʻIʻiwi population than growing human development is the combined effect of avian malaria and climate change. Avian malaria is caused by the bite of an infected mosquito. Mosquitoes are found at warmer temperatures and thus, at lower elevations. Avian malaria is very dangerous to the ʻIʻiwi, demonstrated by a laboratory study that found 90% of the birds died when exposed to a single bite of an infected mosquito. The threat of avian malaria is pushing the ʻIʻiwi to higher elevation, which is demonstrated by recent monitoring. Although the birds can be found between 300 and 2,900 meters, currently, most of the population inhabits forest between 1300 and 1900 meters.

You may now be asking, how is climate change involved? Increased temperatures in Hawaiʻi as a result of climate change, means that mosquitoes can survive at higher and higher elevations. This in turn means that the ʻIʻiwi is going to be continuously pushed up and out of its habitat.

Fortunately for the beautiful ʻIʻiwi, the Center for Biological Diversity petitioned the U.S. Fish and Wildlife Service to categorize the ʻIʻiwi as threatened or endangered under the Endangered Species Act. In July of 2011, these two organizations reached an agreement that the Service would propose for the ʻIʻiwi to be listed as threatened by 2012. It has now been proposed for protection, and the Service has asked for more scientific data to assist in their review of the species.

Now that you know the controversy surrounding this species, it is also important to appreciate its characteristics as a pollinator. The decurved beak of the ʻIʻiwi allows it to get the nectar from flowers with a similar shape of the family Campanulaceae. However, their main food source is the flowers of the tree ʻōhia (Metrosideros polymorpha).

Historically, native Hawaiians would adorn feather capes made from the ʻIʻiwi. These feather capes were highly valued for their beauty. This bird deserves our attention for its beauty, ecological role, and historic value.

For Additional Information

• BirdLife International (2018) Species fact sheet: Iiwi, Vestiaria coccinea.
• Atkinson, C.T., R.J. Dusek, and W.M. Iko. 1993. Avian malaria fatal to juvenile I'iwi. Hawaii's Forests and Wildlife Newsletter 8(3): 1, 11.
• Center for Biological Diversity: SAVING THE 'I'iwi
• Fancy, S. G., and C. J. Ralph. 1998. 'I'iwi (Vestiaria coccinea) (PDF). In The Birds of North America, No. 327 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA.