Learn about the i'iwi

The I’iwi is a bright red honeycreeper which was once one of the most common forest birds in Hawai’i, to which it is endemic. Historically, more than 50 honeycreeper species inhabited the Hawai’ian Islands. Of these, 17 are left today, of which 15 are listed as endangered. Having evolved from the same ancestor, by finding different niches, different species formed different behaviours and specialisms toward different food sources. This adaptive radiation can be seen in the bill morphology of the different species, which is influenced by what they eat – some feed on insects, some on fruit, and some on flower nectar. Though they occasionally feed on small insects, the long decurved bill of the I’iwi is particularly adapted to retrieving nectar from similarly shaped flowers. Many native plant species that provided stable food sources for lots of forest birds started to decline with the arrival of settlers on the Hawai’ian archipelago.

 

Humans altered the landscape and introduced invasive plant and animal species that greatly changed the native ecosystem.

 With humans came cattle, pigs, cats, rats, and mongoose which grazed on vegetation, preyed on wildlife, increased competition for food, and spread diseases. Invasive plant species posed a further threat as they decreased native plant biodiversity within the ecosystem, replacing vegetation that provided food and habitat for native wildlife.

 

When a species is introduced into an ecosystem it is not naturally part of, the consequences can be severe.

While there is a chance the alien species may not thrive in the new environment, there is also chance of it causing huge environmental harm. If the new conditions for introduced species are favorable, it may allow it to easily reproduce and directly compete for resources with native species. With the absence of natural predators, populations of introduced species can explode and suppress those of native species. Having evolved in island isolation and therefore being less able to develop defense mechanisms, Hawai’ian birds were highly susceptible to the newly introduced threats. As a result, their numbers dropped rapidly. Avian malaria is a disease spread through an invasive mosquito that previously could be avoided by finding refuge in colder, high-altitude forests, less habitable for mosquitoes. However,

 

with temperatures rising as a result of climate change, mosquitos are now able to extend their range much higher in elevation, leaving native bird species much less habitat to retreat to.

Avian malaria remains one of the biggest threats towards Hawai’ian bird populations today with affected I’iwis having 95% chance of suffering immediate fatality or severe physical weakening from an infected mosquito. In the event the infection is not immediately fatal, the lack of ability to feed or hide from predators will prove fatal shortly after. Because of this threat, the I’iwi, usually a seasonally migrating species following flower blooms at all altitudes, has been forced to adjust its behaviour and limit its foraging to high altitude areas. Nectar from flowers of the Ohi’a tree, found in high-elevation forests, provides the I’iwi with one of its main food sources and its only nesting tree. Unfortunately, this species has been taken over by a fungus. Identified and named “Rapid Ohi’a death” in 2014, trees are susceptible to the fungal pathogen at all ages and die from the disease within 2 weeks. Being the most abundant native tree in the state of Hawai’i, the Ohi’a tree is not only critical to the survival of native bird species, but provides an integral part of the health of Hawaii’s whole ecosystem. With declining Ohi’a populations, the I’iwis habitat becomes more fragile. The fungus has been detected on the islands of Maui, Kaua’I, Hawai’I island, and O’ahu, which are home to the largest remaining percentage of I’iwi populations. In order to minimize the spread of the fungus, regulations on the transport of Ohi’a trees between islands have been implemented. Furthermore, moving any part of the Ohi’a tree or any of the surrounding soil to new areas should be avoided, which extends to the cleaning of hiking and working gear. The I’iwi is now listed as vulnerable on the IUCN red list (International Union for the Conservation of Nature) and has been protected by the Endangered Species Act since 2017. These actions have motivated attempts to protect its remaining habitat and control of disease carrying mosquito populations. There are lots of opportunities to support the conservation of the I’iwi such as volunteering with or donating to organisations that invest in the protection of Hawai’ian forest birds. It is a great help just to be aware of the impact that alien species can have on foreign ecosystems and help prevent their introduction, especially in this case as island ecosystems are particularly vulnerable due to their highly specialized species, with small populations numbers.

 

While islands are usually rich in biodiversity, they also show the highest extinction rate of species once these fragile ecosystems are thrown out of balance.

The topographical, climatic, and volcanic conditions that Hawai’i has to offer provide ideal living conditions not only for the I’iwi but to an array of endemic, endangered species, on the brink of extinction. Native species not only have an incredibly high ecological, but also historical and cultural value and deserve to be preserved for future generations.

Animal footprints copy 1 1 1 1 I'iwi

Species Fun Fact

The I’iwi is considered sacred in Hawai’ian culture – their bright red feathers are said to have been painted by the demi-god Maui himself. They have been used in a variety of Hawai’ian crafts, and quickly became a symbol of royalty and societal rank, to be used only for special occasions.

When you purchase a painting or print, 5% of the proceeds will be donated to a conservation effort – at no extra cost to you.

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