‘I‘IWI} Vestaria coccinea
DESCRIPTION: ‘I‘iwi have curved, salmon-colored bills, bright red bodies and black wings and tails. They are small birds, generally about 15 centimeters long and 16-20 grams in weight. Males are slightly larger than females. Immature ‘i‘iwi are a pale yellow, splotched with brown.
HABITAT: ‘I‘iwi occur in higher-elevation habitats (above 1,250 meters), breeding and wintering primarily in forests dominated by native ‘ōhi‘a and koa trees.
RANGE: Once widely distributed in native forests on all major Hawaiian islands, the species is now mostly restricted to elevations above 1,250 meters on the islands of Hawaii, Maui, Kauai, Oahu and Molokai. ‘I‘iwi are declining everywhere in Hawaii except at high elevations on east Maui and northeast Hawaii Island.
MIGRATION: ‘I‘iwi often travel widely in search of ‘ōhi‘a flowers, responding to seasonal flowering patterns and sometimes moving to lower elevations, where they are exposed to deadly disease.
BREEDING: ‘I‘iwi pairs are reported to produce on average only 1.33 chicks per year, with the lowest annual survivorship reported for any existing species of honeycreeper. Females typically lay two eggs, and they alone are thought to incubate eggs and brood young, while males provide females with food. Breeding takes place predominantly from February to June, and is usually associated with peak flowering of ‘ōhi‘a. ‘I’iwi maintain a monogamous pair bond throughout the breeding season.
LIFE CYCLE: No data is available on the ‘i‘iwi’s lifespan; however, the maximum lifespans for other Hawaiian honeycreepers range from five to 12 years.
FEEDING: The ‘i‘iwi uses its long bill to extract nectar from flowering plants in the bellflower family, which have become far less common in Hawaii over the past century.
‘I‘iwi will also glean invertebrates from foliage.
THREATS: The ‘i‘iwi is in imminent danger from climate change, which threatens to shrink its range by pushing suitable habitat to ever-higher elevations. The bird has also for some time been threatened by disease, urban and agricultural development and nonnative species that contribute to habitat destruction, facilitate the spread of disease and directly prey on ‘i‘iwi.
POPULATION TREND: The ‘i‘iwi population is estimated at 360,000 birds, with about 90 percent of these on Hawaii Island and the remainder mostly on east Maui. Population trends show declines on all islands, but with some stability in areas above 1,250 meters in elevation, where disease incidence is currently low or absent.