The Puaiohi, or small Kauai Thrush, is a distinctive, rare, olive-brown thrush that is restricted to remote, high-elevation forest on the island of Kaua‘i in the Hawaiian Islands. It is the most divergent of the Hawaiian thrushes vocally, morphologically, and behaviorally. These differences led to its immediate recognition as a unique species while taxonomists struggled with the status of other Hawaiian thrushes.
First collected in 1891 by Henry Palmer at Halemanu (literally “bird house”), near the present entrance to Köke‘e State Park, this Kaua‘i endemic was the last of that island's avifauna to be discovered by Western ornithologists (Banko 1980b, Olson and James 1994a). Even in the late 1800s, while Kaua‘i's native avifauna appeared intact, the Puaiohi was considered exceedingly rare (Perkins 1903).
Cryptic, sedentary, and occupying inaccessible ravines in remote tracts of the Alaka‘i Swamp, the Puaiohi only slowly revealed details of its life history, following the initial study by R. C. L. Perkins in 1895. On an expedition in 1960, ornithologists were shocked to find 17 individuals of this “nearly extinct” species, and for the first time the Puaiohi was classified as common in certain portions of its range (Richardson and Bowles 1964). U.S. Fish and Wildlife Service (USFWS) surveys during 1968 to 1973 corroborated this finding but recognized the Puaiohi's precarious status because of its extremely restricted range (Sincock et al. 1984). The 1981 Hawaiian Forest Bird Survey which censused a portion of the Puaiohi's range further reinforced this conclusion by detecting only 13 Puaiohi (Scott et al. 1986).
Two hurricanes devastated Kaua‘i's forest bird populations in 1982 and 1992, and subsequent surveys yielded little information, except that the Puaiohi had survived. The discovery of a nesting population of Puaiohi in 1995 sparked support for a cooperative research and recovery effort. Early research results are promising, with the popula-tion exceeding 200 individuals and showing high annual productivity (U.S. Geological Survey/Biological Resources Division [USGS/BRD] unpubl.). However, the Puaiohi remains vulnerable, with most of the population restricted to 2 core areas totaling less than 10 km2and dramatic losses in distribution in the last 25 years (Sincock et al. 1984, Scott et al. 1986, USGS/BRD unpubl.).