Overview
The ‘I’iwi (Drepanis coccinea), also known as the Scarlet Honeycreeper, is an internationally celebrated icon of the Hawaiian archipelago and a textbook triumph of evolutionary adaptive radiation. Clothed in a blazing plumage of scarlet-vermilion feathers accented by jet-black wings and a distinct white secondary patch, this dazzling forest bird is most famed for its elongated, decurved, salmon-pink sickle-shaped bill. Flitting energetically through the mist-shrouded canopies of montane rainforests, the ‘I’iwi serves as an indispensable keystone pollinator for Hawaii’s endemic flowering flora.
Biology and Physical Characteristics
The morphological architecture of Drepanis coccinea is an exquisite example of co-evolutionary floral mutualism. Its extraordinarily long, curved bill is custom-molded to reach the deep nectar reservoirs of tubular Hawaiian lobeliads (such as Clermontia and Cyanea) and brush-like crimson blossoms of native ʻōhiʻa lehua (Metrosideros polymorpha). Inside its bill rests a specialized brush-tipped tongue that siphons nectar via rapid capillary action. Their flight produces a distinctive, audible creaking or whirring sound generated by specialized primary wing feather structures, accompanied by a rich repertoire of resonant, flute-like bell whistles.
Behavior and Ecology
Operating as nomadic nectar wanderers, ‘I’iwi travel extensively across vast elevation gradients, tracking seasonal blooms of ʻōhiʻa and koa trees across rugged volcanic slopes. They are fiercely territorial around rich floral aggregations, aggressively chasing away competing honeycreepers and Japanese white-eyes with sharp scolding calls. Pairs form monogamous bonds during the winter breeding season, building cup-shaped nests of ʻōhiʻa twigs, moss, and lichen high in the tree canopy where females incubate two speckled, pale-buff eggs while being fed regularly by their mates.
Conservation and Human Impact
Once abundant from sea level to mountain peaks across all major Hawaiian islands, ‘I’iwi populations have suffered drastic declines and are classified as Vulnerable by the IUCN. The primary driver of collapse is avian malaria and avian pox transmitted by invasive southern house mosquitoes (Culex quinquefasciatus), which restricts the birds strictly to cold highland elevations above 4,000 feet where mosquito larvae cannot survive. Invasive feral pigs that trample forest understories, rapid ʻōhiʻa death (ROD) fungal pathogens, and climate change driving mosquitoes into high refugia remain acute hazards. Groundbreaking landscape-scale conservation using incompatible male mosquito techniques (Wolbachia) is actively deployed to save the species.
Interesting Factoid
Historically, ancient Hawaiian nobility (aliʻi) harvested hundreds of thousands of vibrant red feathers from ‘I’iwi to construct magnificent royal feather cloaks (ʻahu ʻula) and ceremonial helmets (mahiole), symbolizing divine mana and sovereign leadership.
Last updated: October 2026