領角鴞和黑冠麻鷺繁殖期與氣溫的相關性

Relationships between Air Temperature and Reproduction Timing for Collard Scops Owl (Otus bakkamoena) and Malayan Night Heron (Gorsachius melanolophus)

在全球暖化日益受到重視的當下，國際間已有許多研究探討氣候變遷對野生動物繁殖的影響，但台灣針對此議題的野外研究仍十分缺乏。本研究利用特有生物研究保育中心野生動物急救站的落巢幼鳥案例，分析鳥類繁殖時間和氣溫的相關性，以案例數最多的領角鴞（Otus bakkamoena）和黑冠麻鷺（Gorsachius melanolophus）為研究對象。本研究先利用圈養的幼鳥建立研究對象的生長曲線，再選取中部地區的案例，以送達急救站時的落巢幼鳥體重回推該巢的繁殖時間，總計獲得領角鴞9 年133 巢和黑冠麻鷺5 年56 巢的繁殖資料。將各年繁殖起始時間與繁殖季前各個月份的平均氣溫進行迴歸分析，領角鴞和黑冠麻鷺的繁殖時間分別與前一年11 月（p < 0.05）和12 月（p< 0.01）的月均溫有顯著相關，該月份氣溫上升則隔年的繁殖時間將會提前。在當前暖化的趨勢下，野生動物繁殖期提前對生態的影響值得關注。

As global warming has drawn our increasing concerns, many studies have focused on whether climate change would affect the timing of wildlife reproduction. We used orphaned nestling data of two avian species, the Collard scops owl (Otus bakkamoena) and the Malayan night heron (Gorsachius melanolophus), obtained by the Wildlife First Aid Station of the Endemic Species Research Institute of Taiwan to analyze the relationships between air temperatures and their reproduction timing. A growth curve model was built and daily growth rate by weight of each of the species was determined with the data of captive nestlings at the station. Egg deposition date of each of the orphaned nestlings was then estimated with the growth model. There were 133 orphaned nestlings of the Collard scops owl from Central Taiwan for nine years and 56 nestlings of the Malayan night heron for five years. A regression analysis was conducted between the estimated egg deposition dates and the monthly average air temperatures prior to the breeding seasons. The egg deposition dates were significantly correlated with the average air temperatures of the months of previous November (p＜0.05) for the Collard scops owl, and previous December (p＜0.01) for the Malayan night heron. When monthly average air temperatures of these months rose, the egg deposition dates of the two species proceeded earlier in the following year. Further studies are needed to examine whether other avian species have the same trend of air temperature and breeding time relationship and what is the mechanism.