By Samuel M. ‘Ohukani‘ōhi‘a Gon III, Ph.D.

Cloaked in the light mist of the East Maui forest, you wait.  Craning your neck upward, squinting against the pale back-lit glare in your binoculars, you search for any of those small, colorful endemic forest birds of the Hawaiian islands. 

As you rest your eyes and stretch your neck from this bird-searching exercise, you notice that right in front of you, at eye level, is the spectacular scarlet colored ‘i‘iwi, which has flown down from the canopy to feed on the blossoming flowers of a native raspberry.

This raspberry, known as the ‘ākala, is amazing in its own right. An almost thornless specimen, it reveals the effects of evolving in an island environment devoid of large herbivores. The pale magenta blossoms and garnet red fruits hanging from arching branches dab the understory throughout the months of April and May, creating the feeling of being immersed in an impressionist painting.

During its bloom, the ‘ākala attracts native nectar-feeding forest birds like the ‘i‘iwi down from the upper canopy to a more comfortable viewing level. Up in the canopy, among the red pompom-like blossoms of the ‘ōhi‘a lehua trees, the ‘i‘iwi is more difficult to spot, because it keeps to the interior leaves of this prominent tree. 

Juvenile 'i'iwi in pōlena form

Bill Built for Sipping

While the ‘i‘iwi feeds in the understory, you can witness a supreme demonstration of evolutionary adaptation: the bird’s salmon sickle-shaped bill is a singular match for the sickle-shaped lobelia flowers on which it also feeds.

The brilliant scarlet feathers, and contrasting black wings and tail of the ‘i‘iwi certainly command your attention as it whirs by you in the verdant foliage of the Hawaiian rain forest. However, as it matures, the ‘i‘iwi undergoes dramatic changes of feather colors. This is reflected by the variety of Hawaiian names used to describe the immature phases of the ‘i‘iwi. One young form is called pōlena (meaning flush with yellow) and instead of scarlet, is aptly yellowish green.

As you wait for the ‘i‘iwi to alight on that ‘ākala blossom in front of you, listen for its loud, unmistakable “rusty-hinge” call — one of the first lessons for the novice Hawaiian birdwatcher.

Threatened With Extinction

One of the most beautiful birds in Hawai'i, the 'i'iwi was prized by Hawaiians for its striking vermillion feathers, which were used to make feather capes, helmets and other symbols of Hawaiian royalty. Today, the ‘i‘iwi is threatened by habitat destruction, introduced predators and avian diseases. This beautiful bird is now extinct on the island of Lāna‘i, and is considered extremely rare and vulnerable to extinction on O‘ahu and Moloka‘i.

Although the ‘i‘iwi was once abundant on each of the main Hawaiian high islands, the introduction of mosquitoes to the islands in the early 1800s has significantly impacted its population. Mosquitoes transmit bird malaria, and native birds are particularly susceptible. 

Fortunately, the ‘i‘iwi is still common in mosquito-free areas above 1,000 meters (3,280 feet) elevation on the islands of Hawai‘i, Maui, and Kaua‘i. Feral pig populations and global warming threaten to carry mosquito populations to higher elevations if left unchecked. These introduced mammals create wallows in which mosquitoes breed. The mosquitoes, in turn, spread avian malaria to native birds which, having evolved in isolation, are defenseless against these introduced diseases. Two weeks after a single bite from a disease-laden mosquito, an ‘i‘iwi will lie dead on the forest floor.

The Nature Conservancy is working with its partners to keep feral pigs and other ungulates out of the upper elevation forests so that many of Hawaii’s native species can find refuge and survive well into the future.

Sam Gon is senior scientist and cultural advisor for the Nature Conservancy of Hawai'i.

Nature picture credits (top to bottom, left to right): Photo © Jim Denny ('i'iwi on koli'i); Illustration © Wilson/J.H. Evans (juvenile 'i'iwi in pōlena form); Photo © Rob Shallenberger/TNC ('i'iwi sipping nectar from mamane blossoms).