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A healthy Hawaiʻi ʻamakihi (credit: Noah Khan, U.S. Fish and Wildlife)

The University of Hawaiʻi at Hilo, in collaboration with the Pacific Island Ecosystems Research Center of the U.S. Geological Survey, announces the online availability of the report, “Distribution and prevalence of knemidokoptic mange in Hawaiʻi ʻamakihi on the island of Hawaiʻii.” The Hawaiʻi ʻamakihi (Hemignathus virens) is a species of Hawaiian honeycreeper that evolved in the forests of Hawaiʻi and is found nowhere else in the world.

“Scaly leg” deformities

The report summarizes the current status of an emerging infectious disease, knemidokoptic mange, in native birds on the island of Hawaiʻi. Knemidokoptic mange, sometimes called “scaly leg,” was first detected in the native bird Hawaiʻi ʻamakihi in 2007 by the lead author of the report, Jacqueline Gaudioso, then a graduate student in UH Hilo’s tropical conservation biology and environmental science program and now a USGS employee. The disease is caused by the skin-burrowing mite, Knemidokoptes jamaicensis, and may result in severe deformities of the feet and drops in population levels.

“Although Hawaiʻi ʻamakihi are becoming more common in lowland forests, emerging infections like knemidokoptic mange may slow, or even halt, population recovery,” says Dennis LaPointe, a research ecologist with the USGS Pacific Island Ecosystems Research Center and an author of the report.

Impacts on endemic Hawaiʻi forest birds

The results of an island-wide survey of key native forest bird habitats revealed an infestation limited to Hawaiʻi ʻamakihi but spreading from low elevation, leeward Mauna Loa, to higher, leeward elevations, and west to low elevation forests in Puna.

Analysis of preliminary findings indicates some correlations between avian malaria, wetter habitat, and knemidokoptic mange, and provides some evidence of an impact on individual survival. The report adds to the understanding of this emerging infectious disease in wild bird populations and offers some insights into management of disease at the local level.

The report has been published by UH Hilo’s Hawaiʻi Cooperative Studies Unit.

Visit the UH Hilo Stories website for more.

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