| Summary: | 碩士 === 國立臺灣師範大學 === 生命科學系 === 104 === Short-eared owl (Asio flammeus) has suffered from a continuing population decline since the 1970s. Habitat loss and degradation of wintering grounds likely contribute to their decline. Although as one of the important wintering habitats for the short-eared owl in Asia, wintering information of this owl in Taiwan is very limited. In this study, I aim to employ radio tracking technology to quantify wintering short-eared owl in Taiwan. Moreover, we summarized the wintering pattern of the short-eared owl from 2007 to 2015 in Taiwan using capture period, capture localities, and sex identification, in collaboration with Taichung Wildlife Conservation Group. My results indicated that the wintering period of the short-eared owl lasts for eight months in Taiwan, with the number of captures picking in December and March. The sex ratio is female-biased, with females constituting 79% of the whole wintering population. The home range did not differ between males and females, with a 95% core area ranging between 13 and 2,282 hectares (mean = 444 ha), and a series of 50% core areas ranging between 0.2 and 897.0 hectares (mean = 158.9 ha). The owls prefer grasslands and they stayed in agriculture lands for nocturnal roosting sites. The average days of each core area used by one owl was 10.4 days, which suggests that the owls had short-term site fidelities at small spatial scale. Conserving a certain amount of farmlands and grasslands is crucial to the conservation of the short-eared owls.
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