The Puaiohi or the Small Kauai Thrush, (Myadestes palmeri), is a rare thrush that is endemic to the Hawaiian island of Kauai. It is closely related to the other 4 endemic Hawaiian Thrushes, the Kamao, the Olomao, the Omao, and the ??maui. It was first collected by Henry Palmer in 1891 at Halemanu around the entrance to the Koke'e State Park.
The plumage is mostly nondescript, with slaty-brown upperparts and a light gray breast and belly below. Birds have a black bill and pinkish feet. A white eye ring is also fairly prominent and helps distinguish this bird from the other Hawaiian Thrushes. Both males and females are highly similar in appearance. Juveniles show a pattern tansitioning from a spotted whitish-buff above to a scalloped gray-brown below.
Distribution and habitat
Historically, this species has always been considered rare, favoring forested ravines above 1050 meters. Puaiohi are restricted to the center and southern parts of the Alakai Reserve. 75% of the breeding popuation occurs in only 10 sq. km. of forest.
Diet and behavior
Outside the breeding season, most (82%) of the diet takes up fruit and berries, the remaining makeup of the diet being insects and other inverterates . Some important food sources include fruits of the native Olapa (Cheirodendron trigynum), Lalapa (Cheirodendron platyphyllum),Ohiaha (Syzygium sandwicensis) and Kanawao (Broussaisia arguta). In the breeding season, over fifty percent of the diet shifts to invertebrates. The song is varied, consisting of a simple till to a complex wheezing, and high pitched squeal described as a squeaking rather resembling a metal wheel needing lubrication. Males can be found singing throughout the year, but do so with increasing frequency as breeding season approaches, peaking from April to May.Nesting has been recorded as early as March, to as late as mid-September. Nesting pimarily occurs in cavities or ledges of cliff faces, concealed by mossed and ferns , but tree cavities are also used. Females are the sole nest builders, which can take up to 7 days. She also incubates the eggs, and broods and feeds the young birds while still in the nest. Eggs (usually 2 in are laid in the wild) are colored grayish-green to a muted greenish-blue with irregular reddish-brown splotches.. Eggs hatch after 13-15 days. After fledging, the males become primary food providers to the young, while the female attempts a second brood. Females will also attempt to renest if the first attempt fails.
Status and protection
According to recent data, population estimates range from 200-300 birds, and have remained somewhat stable since 1973, although a study published in 1986 in estimated a population of approximately 100-125 birds. Puaiohi populations are vulnerable to drought, hurricanes, and mammalian predation of both eggs and young. Avian malaria also has been shown to affect many birds, but a few birds have shown some resistance. (C. Atkinson, USGS, unpublished data). Feral domesticated livestock (pigs and goats) also negatively affect populations of birds by degrading habitat, as has competition from many invasive plants and animals. The Puaihoi was added to the United States Federal Endangered Species list on March 11, 1967. In 1995, a captive breeding program was established.. Some birds from this progam are now being taken back to the Alakai to supplement the wild population.