石碇地區台灣紫嘯鶇的繁殖及其影響因子

繁殖成功率會影響鳥類族群的存續。而影響鳥類繁殖成敗的因子如天氣、巢位特徵、棲地特徵等會直接或間接地影響鳥巢存活率。本研究室長期在石碇地區記錄台灣紫嘯鶇(Myophonus insularis)的繁殖情況，已知繁殖季早期氣溫與其繁殖起始日呈負相關，天敵風險高的巢區繁殖成功率較低。本研究更進一步評估巢位及棲地特徵與天氣對台灣紫嘯鶇繁殖成功率的影響，以及描述石碇地區台灣紫嘯鶇的繁殖現況。利用Program MARK中的鳥巢存活模式(Nest survival)計算每日鳥巢存活率(Daily nest survival)，將天氣、巢位特徵、棲地特徵等變數放入模式中，篩選影響鳥巢繁殖成功的因子，選出較佳模式。結果顯示石碇地區紫嘯鶇的鳥巢存活率隨著溫度升高而降低，連續10日未降雨日數、極端降雨事件與人類巡巢的行為皆會對其存活率造成負面影響。但雨量不會影響台灣紫嘯鶇的繁殖起始日期。此外，台灣紫嘯鶇也會因有巢內寄生蟲而改變巢位。雖然從2008年至2014年石碇地區台灣紫嘯鶇的密度呈上升趨勢，但未來台灣氣候呈現暖化、降雨日數下降、極端天氣事件增加的情形，依據本研究台灣紫嘯鶇的鳥巢存活率模式推論，將對台灣紫嘯鶇的繁殖成功率有負面的影響。

關鍵字

台灣紫嘯鶇；繁殖生物學；繁殖成功率

並列摘要

Reproductive success is closely correlated with the survival of a bird population. Several factors, sach as weather, nest site and habitat characters may directly or indirectly affect reproductive success. We have been carried out a long-term monitoring on the Taiwan Whistling Thrush’s (Myophonus insularis) breeding performance at Shiding in northern Taiwan. Preliminary information of reproductive biology of this species has been established by previous studies. The objectives of this study were to estimate the effect of weather, nest site character, and habitat character on Taiwan Whistling Thrush’s nest survival rates , and to describe the general situation of its reproduction at Shiding. We analyzed the daily nest survival of Whistling Thrush by using the nest survival model in Program MARK. The results showed that high temperature, extreme rainfall events, droughts when ≥ 10 days had passed with 0 mm total rainfall , and observer effects had significant negative influence on Taiwan Whistling Thrush’s nest survival rate. However, precipitation did not affect the initiation date of first egg of Taiwan Whistling Thrushes. It suggested that the Taiwan Whistling Thrush might change its nest site when ectoparasites occurred. Although nesting density of the Taiwan Whistling Thrush at Shiding increased from 2008 to 2014. The results of this study suggests that climate change, such as global warming, decrease of rainy days, and increase of extreme weather events, may have negative effects on Taiwan Whistling Thrush’s survival.