| Kiwikiu (Maui parrotbill) | |
|---|---|
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Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Fringillidae |
| Subfamily: | Carduelinae |
| Genus: | Pseudonestor Rothschild, 1893 |
| Species: | P. xanthophrys |
| Binomial name | |
| Pseudonestor xanthophrys Rothschild, 1893 | |
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Thekiwikiu orMaui parrotbill (Pseudonestor xanthophrys) is a species ofHawaiian honeycreeperendemic to the island ofMaui inHawaii. It can only be found in 50 square kilometres (19 sq mi) ofmesic andwet forests at 1,200–2,150 metres (3,940–7,050 ft) on the windward slopes ofHaleakalā.[3] This species iscritically endangered, with an estimated population in 2016 of 250-540 individuals, but more recent estimates of less than 150 individuals.[4] Fossil evidence indicates that the bird could at one time be seen indry forests at elevations as low as 200–300 metres (660–980 ft), as well as on the island ofMolokaʻi.[5]
The Maui parrotbill is one of the largerHawaiian honeycreepers, measuring 14 centimetres (5.5 in)[4] and with a mass of 20–25 grams (0.71–0.88 oz). The bird is yellow on the breast, cheeks, and belly, olive-green on the wings, crown, tail, and back, and has a bright yellowsupercilium. The uppermandible of the bird'sbeak is hooked and dark gray, while the lower mandible is chisel-like and pale ivory. Males are longer-winged, larger-billed, and heavier than females. Juveniles are gray-green above and light gray ventrally.[5]
Its call is a short "chip", which is similar to theMaui Nui ʻalauahio, chirped every three to five seconds. It song consists of "cheer" notes that are slower and richer than theʻākepa. It also has a short song that sounds like "cheer-wee".
The Maui parrotbill is aninsectivore. It uses its large beak and powerful jaw muscles to removebark and wood from smalltrees andshrubs such asʻākala (Rubus hawaiensis),kanawao (Broussaisia arguta), andʻōhiʻa lehua (Metrosideros polymorpha), eating theinsects underneath. The Maui parrotbill also bites openfruits in search of insects. It is fond ofmoth pupae andbeetlelarvae. Pairs of birds forage in a territory of 2.3 hectares (5.7 acres), which they must defend from competing parrotbills.[5]
The Maui parrotbill ismonogamous and breeds between November and June. Females build a cup-shaped nest out ofUsnealichens andpūkiawe (Styphelia tameiameiae) twigs, placing it 12 metres (39 ft) above the forest floor. Pairs raise a single nestling per season. The female incubates it for 16 days. Fledglings remain with their parents for five to eight months as they learn how to forage.[5]
The Maui parrotbill currently lives only in undisturbedwet forests dominated byʻōhiʻa lehua (Metrosideros polymorpha) and small patches ofʻōhiʻa-koa (Acacia koa)mesic forest. Its habitat exhibits a dense understory of smalltrees,shrubs,epiphytes,ferns, andsedges,[5] centered between Puʻu ʻAlaea, Kuhiwa Valley,Lake Waianapanapa, and upperKīpahulu Valley, an area less than 2,020 hectares (5,000 acres), at elevations of 1,310–2,070 metres (4,300–6,790 ft).[6]
As far as anyone can determine,Pseudonestor xanthophrys had not historically had a common name in the Hawaiian language. The Hawaiian namekiwikiu was developed by the Hawaiian Lexicon Committee, who was contacted by the Maui Forest Bird Recovery Project to select an appropriate name. A naming ceremony was held in the bird's habitat in September 2010. The "kiwi" part of the name means bent or curved (e.g., sickle-shaped), which refers to the shape of the bill of this bird. "Kiu" has a double meaning, referring both to the bird's secretive ways and to a cold, chilly wind, such as the breezes in the bird's habitat.[7][8]
The Maui parrotbill's naturalhabitat ismesic andwet forests. It is threatened byhabitat loss. Much of the land in the parrotbill's historic range was changed for agricultural purposes, timber production and animal grazing. Introduced pests, such as mosquitoes, rats, and feral ungulates directly and indirectly affect the parrotbill's survival. Mosquitoes spreadavian malaria, which the parrotbill is susceptible to, rats prey upon the birds' eggs and young, and feral pigs uproot the low-lying vegetation that the parrotbill forages in. Pigs additionally create wallows, which serve as breeding grounds for avian malaria-infected mosquitoes.
The Maui parrotbill was listed as an endangered species in 1967 under theEndangered Species Preservation Act. It is also part of the Maui-Molokai Bird Recovery Plan in 1984, which led to fencing areas of East Maui and removing feral ungulates. The recovery plan also included a captive breeding program, which produced its first chick in 2003. Field research is primarily done by the Maui Forest Bird Recovery Project.[9]
A 2009 survey of the Waikamoi Preserve estimated that there were about 20 birds per square kilometer in the windward preserve near the summit of Haleakalā, indicating that the population was holding steady or possibly increasing. A contributing factor is that native shrub cover in Waikamoi has tripled in the past 15 years. A previous study found about half the density. The preserve contains about 25 percent of the population, while most of the rest is in the Hanawi Natural Area Reserve. The birds were once found throughout Maui and Molokai. A 2019 effort is underway to reintroduce Maui parrotbill to leeward Maui, where it had been previously extirpated.[10] However, more recent studies have found that the population in fact dramatically declined after 2001, asclimate change has made more of the higher-elevation forests that the kiwikiu inhabits more hospitable to mosquitoes. A translocation effort to a restored area on theleeward slopes ofHaleakalā in 2019 failed after most birds succumbed to avian malaria, despite otherwise doing well in the habitat.[11]
It has been predicted that if the mosquito population continues increasing, Maui parrotbills may facefunctional extinctionin the wild by 2027. Due to this, there have been several conservation efforts planned by the Maui Forest Bird Working Group, including at least temporarily fostering a sizeable captive population on zoos in themainland United States (previous ex-situ conservation efforts were limited to only Hawaii), including potentially theNational Aviary inPennsylvania,Smithsonian Conservation Biology Institute inVirginia and theTracy Aviary inUtah, potentially introduce a wild population to theisland of Hawaii as a backup, manage and restore more habitat in Maui for eventual release, develop predator control tools, and perform landscape-scalemosquito control in the bird's native habitat.[12] The captive population will consist of 15 male and 15 female wild birds; removing such a large number of birds from an already-small wild population may accelerate the timeline of the species' possible extinction in the wild, but it can allow for a safe population to be bred in captivity away from avian malaria.[11]
