LIHUE — A new study provided the first rigorous population estimate of an endangered bird species found only on Kauai.
The Puaiohi or Small Kauai Thrush, has an estimated population of 494 birds. Scientists have long believed that the species was very rare, had evidence as to the exact count due to the bird’s secretive demeanor and the inaccessible terrain they inhabit in Kauai’s Alakai Plateau.
The Puaiohi was listed as endangered in 1967.
“Population estimates are a cornerstone of species conservation efforts,” said Dr. Eben Paxton of the U.S. Geological Survey, a co-author of the study. “They are the benchmark against which managers monitor the success of their conservation efforts. If managers don’t know how many individuals exist to begin with, it is impossible to tell if a population is increasing or decreasing in response to conservation activities.”
The Puaiohi’s range and population size has been reduced by a number of threats: habitat loss and degradation, non-native predators and introduced mosquito-borne diseases, such as avian malaria. The new study also suggests invasive weeds at lower elevation may restrict Puaiohi’s range.
“This study allowed us to estimate Puaiohi distribution in remote parts of the species’ range that are difficult to survey, and identify new hotspots of Puaiohi where we should implement these management activities, which will accelerate the species’ rate of recovery,” said Dr. Lisa Crampton, lead author of the study.
KFBRP, USGS Pacific Island Ecosystems Research Center, Diegmann Science Services, and University of Hawaii Hilo Hawaii Cooperative Studies Unit worked together develop a special methodology to survey this cryptic bird species in this difficult environment and to use both field-collected and remotely-sensed data to generate a population estimate.