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進入《TAIPEI TIMES》 Doctoral student finds more hawk-eagle sounds
A mountain hawk-eagle calls from its nest in an undated photograph. Photo courtesy of the National Pingtung University of Science and Technology via CNA
By Jake Chung / Staff writer, with CNA
A study led by Taiwanese doctoral student Huang Yung-kun （黃永坤） and published in the August issue of the journal Global Ecology and Conservation hopes to shed light on the vocal behavior of mountain hawk-eagles.
The paper is likely the first in the international community to examine voiceprint and quantitative data, Huang said.
Before the paper, there were recordings of two kinds of sounds emitted by mountain hawk-eagles: the sound they make when flying and the sound that hatchlings make when they want to be fed.
Over the past 17 years, Huang said that he has recorded five more sounds that hawk-eagles make: the sound mothers make when asking for food, a warning sound, a sound they make when interacting with their young, a trilling sound and another high-frequency sound.
The functions denoted by the seven sounds are only roughly categorized, Huang said, adding that a single sound might have more than one function.
The sounds emitted by the hawk-eagles are typically on the low end of the spectrum, at about 2,000 hertz （Hz） to 3,000Hz, with high-frequency calls only reaching 6,000Hz, Huang said, adding that the sounds are easily drowned out by birds with louder or more frequent calling patterns, such as the thrush.
The hawk-eagle is considered holy by the Paiwan community, and Paiwan leaders and warriors often wear their feathers to signify their importance, he said.
Due to disappearing habitats and overhunting, the number of mountain hawk-eagles has sharply declined and the population of 300 to 1,400 birds, depending on the calculation method, is considered a category 1 conservation species.
The paper was coauthored by Huang’s former professor at National Pingtung University of Science and Technology, Sun Yuan-hsun （孫元勳）; Chen Hou-chun （陳厚均） of Mahidol University in Bangkok; and Chiang Po-jen （姜博仁） of the Formosan Wild Sound Conservation Science Center.
新聞來源：TAIPEI TIMES
