Vestiaria coccinea, Photo: Michael Lahanas
Vestiaria coccinea (Forster, 1780)
The ʻIʻiwi or Scarlet Hawaiian Honeycreeper (Vestiaria coccinea) is a Hawaiian "hummingbird-niched" species, of the Hawaiian honeycreepers, subfamily, Drepanidinae, and the only member of the genus Vestiaria. One of the most plentiful species of this family, many of which are endangered or extinct, the ʻiʻiwi is a highly recognizable symbol of Hawaiʻi. The ʻiʻiwi is the third most common native land bird in the Hawaiian Islands. There are large colonies of ʻiʻiwi on the islands of Hawaiʻi and Kauaʻi, and smaller colonies on Molokaʻi and Oʻahu; ʻiʻiwi were extirpated from Lānaʻi in 1929. Altogether, the remaining populations add up to a total of 350,000 birds.
The adult ʻiʻiwi is mostly fiery red, with black wings and tail and a long, curved, salmon-colored bill used primarily for drinking nectar. The contrast of the red and black plumage with surrounding green foliage makes the ʻiʻiwi one of the most easily seen Hawaiian birds. Younger birds have a more spotted golden plumage and ivory bills and were mistaken for a different species by early naturalists on Hawaiʻi. The ʻiʻiwi, even though it was used in the feather trade, was less affected than the Hawai'i mamo because the ʻiʻiwi was not as sacred to the Hawaiians. The ʻiʻiwi's feathers were highly prized by Hawaiian aliʻi (nobility) for use in decorating ʻahuʻula (feather cloaks) and mahiole (feathered helmets), and such uses gave the species its scientific name: vestiaria, which comes from the Latin for clothing, and coccinea means scarlet-colored. The bird is also often mentioned in Hawaiian folklore. The Hawaiian song "Sweet Lei Mamo" includes the line "The i'iwi bird, too, is a friend". The bird is capable of hovering in the air, much like hummingbirds. Its peculiar song consists of a couple of whistles, the sound of balls dropping in water, the rubbing of balloons together, and the squeaking of a rusty hinge.
The long bill of the ʻiʻiwi assists it to extract nectar from the flowers of the Hawaiian lobelioids, which have decurved corollas. Since 1902, the lobelioid population has declined dramatically, and the diet of the ʻiʻiwi shifted to nectar from the blossoms of ʻōhiʻa lehua (Metrosideros polymorpha) trees.  ʻIʻiwi also eat small arthropods.
In the early winter in January to June, the birds pair off and mate as the ʻōhiʻa plants reach their flowering maximum. The female lays two to three eggs in a small cup shaped nest made from tree fibers, petals, and down feathers. These bluish eggs hatch in fourteen days. The chicks are yellowish-green marked with brownish-orange. The chicks fledge in twenty-four days and soon attain adult plumage. At one time the difference in appearance between adults and young gave rise to the belief that they were separate species. Observations of young birds moulting into adult plumage resolved this confusion.
Linguists derive the Hawaiian language word ʻIʻiwi from Proto-Nuclear Polynesian *kiwi, which in central Polynesia refers to Numenius tahitiensis, the Bristle-thighed Curlew, a migratory bird. The long decurved bill of the curlew somewhat resembles that of the ʻIʻiwi.
Although ʻIʻiwi are still fairly common on most of the Hawaiian islands, it is rare on Oʻahu and Molokai and no longer found on Lānaʻi. Most of the decline is blamed on loss of habitat, as native forests are cleared for farming, grazing, and development. Even though it is still plentiful in two parts of its range, it is still listed as a threatened species because of small populations in some of its range and susceptibility to fowlpox and avian influenza. In fact a study has shown that ninety percent of all exposed ʻIʻiwi die and the other ten percent were weakened but survived. However scientists have been helping restore the island ecosystem by removing alien or non-native species of plants and animals from critical habitat. Many of these so called removal projects have been done on the Big Island of Hawaiʻi, where efforts continue around Mauna Kea. Populations of lobelia species have declined over the years and because of this the birds are increasingly being found at ʻōhiʻa trees.
Another threat has been the spread of introduced diseases, particularly avian malaria (Plasmodium relictum), which is spread by mosquitoes. In a series of challenge experiments involving avian malaria, more than half of the ʻIʻiwi tested died from a single infected mosquito bite. Thus the ʻIʻiwi generally survives at higher elevations where temperatures are too cool for mosquitoes, and like many disease-susceptible endemic birds is rare to absent at lower elevations, even in relatively intact native forest. The ʻIʻiwi were also removed when the islands forests were cut down and were replaced with farms, plantations, towns, and alien forests. These birds are altitudinal migrants; they follow the growth of flowers as they go from high elevation to low elevation forests. It is thus exposed to harmful low elevation disease organisms and high mortality This migration also makes it hard to assess the total populations on the islands. The birds are able to migrate between islands and it is because of this that the ʻIʻiwi has not gone extinct on smaller islands such as Molokaʻi.
On Molokaʻi, The Nature Conservancy has attempted to preserve habitat by fencing off areas within several nature reserves to keep out pig populations. The pigs create wallows which serve as incubator sites for mosquito larvae, which in turn spread avian malaria.
It was formerly classified as a Near Threatened species by the IUCN, but recent research has proven that it was rarer than previously believed. Consequently, it was uplisted to Vulnerable status in 2008.
1. ^ a b BirdLife International (2008) Vestiaria coccinea In: IUCN 2009. IUCN Red List of Threatened Species. Version 2009.2. www.iucnredlist.org Retrieved on 30 January 2010.
Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License