短耳鴞在臺灣的度冬生態學

Wintering ecology of short-eared owls (Asio flammeus) in Taiwan

曾威(Tseng Wei)

指導教授 ： 林思民

國立臺灣師範大學/理學院/生命科學系/碩士(2016年)

https://doi.org/10.6345/NTNU202204849

摘要

因為棲地消失或破碎化，自1970年來全球短耳鴞族群有逐年下降的趨勢。族群下降的原因主要是人為活動導致繁殖地及度冬地棲地的破壞。臺灣雖然是短耳鴞的度冬地之一，但是對短耳鴞度冬基礎棲地利用資訊瞭解甚少。本研究以無線電追蹤短耳鴞的活動範圍與棲地利用，收集2013及2015年冬季12隻短耳鴞追縱資料，分析短耳鴞日棲點及夜棲點棲地利用類型。經由臺中市野生動物保育學會從臺灣機場防鳥擊網繫放救傷的資料，分析2007年至2015年短耳鴞來臺灣度冬數量、來台時間、捕捉地點以及性別比例，期望瞭解度冬短耳鴞在臺灣的棲地利用模式與度冬期資訊。繫放資料顯示短耳鴞在臺灣度冬期起始於每年10月，結束於隔年5月，由捕獲數量推測短耳鴞每年度冬高峰為12月。度冬期雌鳥比例偏高，佔族群的75%。追蹤期間的活動範圍在性別之間無顯著差異，短耳鴞利用多個核心區域，核心區域利用總和介於13公頃至2282公頃之間，平均為444公頃，單個核心區域利用介於0.2公頃至897.0公頃之間，平均為158.9公頃，顯著大於北美繁殖地的核心利用區域。不同性別棲地利用類型並無顯著差異。短耳鴞傾向利用草生地做為日棲點，而利用農業用地做為夜棲點。核心區域平均利用天數10.4天，顯示在小尺度上棲地忠誠度高；但是在追蹤期間利用多個核心區域（平均數量2.3個），推測可能因棲地品質差而導致游牧型的棲地利用模式。顯示農地與草地的棲地形態對短耳鴞的度冬是重要的因子。

關鍵字

性別比例 ； 鳥擊 ； 棲地選擇 ； 短耳鴞 ； 遷移

並列摘要

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.

並列關鍵字

Asio flammeus ； bird strike ； habitat selection ； migration ； sex ratio

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