S p e c i e s o f t h e M o n t h
E N D A N G E R E D
OAHU I'IWI
Photos by Michael Walther
Click to see our I'iwi photo gallery
The Oahu I'iwi (vestiaria coccinea) has declined severely during the last 100 years and today only a very small population exists in the central Koolau mountains.In the 1890's I'iwi were one of the most abundant and widespread birds on the island.(Wilson and Evans 1890-1899) Munro (1944) stated that this beautiful species was formerly very numerous on Oahu but were greatly reduced by the 1940's.In 1978 Shallenberger and Vaughn stated the Oahu I'iwi was very rare. Today the state of Hawaii lists the Oahu I'iwi population as endangered..
Calls of the 'I'iwi are loud and squeaky, much like a "rusty hinge". 'I'iwi feathers were used extensively in Hawaiian feather work for their bright red feathers and this bird is often referred to in ancient chants. The birds were caught by the royal bird catchers guild who put sticky plant extract on the branches near the flowers that the 'I'iwi would frequent for nectar.
Description: 'I'iwi are brilliant-scarlet birds with black wings and black tails. The secondary feathers of the wings have a white patch. The 'I'iwi bill is long and curved. Both bill and legs are salmon colored. The overall length is about 14 centimeters, and the sexes are similar. The bodies of immature 'I'iwi are splotchy yellow-green with black spots. The red adult plumage first appears on the head and breast (Berger 1981, Pratt et al. 1987, Hawaii Audubon Society 1989).
Ecology: 'I'iwi are most abundant in mesic to wet native Hawaiian forests. Although individuals take nectar from the flowers of 'ohi'a (Metrosideros spp.) trees, the bill appears to be adapted for sipping nectar from the tubular flowers of several lobeliads, such as 'ohawai (Clermontia spp.). 'I'iwi will utilize mamane (Sophora chrysophylla) and mamane/naio (Myoporum sandwicense) dry forests when the trees are in bloom. 'I'iwi also forage for small invertebrates (Berger 1981, Scott et al. 1986).
The last known population of I'iwi on Oahu live in the central Koolau mountains on the leeward slopes between 1700 and 1875 feet elevation. On December 5,1995 several observers detectected a small remnant population while hiking on the Schofield-Waikane trail that were feeding on nectar of the spectacular native white hibiscus. This population is believed to number fewer then fifty birds. Before this 1995 discovery the last time more then a few I'iwi were observed was in 1977, when at least thirteen were found on the southeastern slope of Mount Ka'ala in the Waianae Mountains (Shallenberger1977). I'iwi have also been observed on the Poamoho and Kipapa trails since 1970 but this species is considered extremely rare on Oahu today.
Aloha,
Michael Walther
