都會地區台灣紫嘯鶇的繁殖生物學與雄鳥鳴唱聲之探討

Abstract

本研究分別針對台灣紫嘯鶇(Myophonus insularis)的繁殖生物學以及雄鳥的鳴唱聲進行探討。繁殖生物學方面，本研究於新北市石碇區在2011-2013年間針對本種的繁殖概況進行調查，並結合前人於2006年、2008年及2009年的資料來分析，共累計6年的繁殖資料，合計36個巢區226個繁殖巢。本種窩卵數為1-4顆，產3顆蛋的巢最為常見(64.77%)，產2顆蛋的巢其次(29.53%)。歷年平均窩卵數為2.69±0.56顆(n=193)，平均雛鳥數為2.33±0.72隻(n=150)，兩者於各年間皆無顯著差異。本種的繁殖季可分成早、中、晚三個時期，中期的窩卵數顯著高於早期。以Mayfield法估算2008年、2009年、2011年及2012年等完整觀察年度之繁殖成功率，各年依序為47.0%、41.7%、34.7%及37.2%；早、中、晚繁殖時期則分別為43.7%、35.4%及26.11%，成功率隨繁殖季推延逐漸下降，晚期繁殖失敗比例明顯較高。繁殖失敗主因為天敵捕食(63.44%)，其次為蛋未孵化(21.51%)。由研究期間的觀察，推測蛇類為本種繁殖期主要巢天敵，而蛇類較易接近的巢區類型實際受天敵捕食的比例亦顯著較高。台灣紫嘯鶇各年開始繁殖的時間與3月1日-3月10日之平均日均溫變化呈現顯著的負相關，當氣溫越低的年度，繁殖則較晚開始，進而縮短繁殖期天數減少繁殖次數及總窩卵數，使該年生產力較低。 雄鳥鳴唱聲的探討方面，本研究於2011年至2013年在台北市南港區針對6隻雄鳥進行野外錄音，共錄得213個唱陣，4525個音段，其中共辨識出23首歌曲型，223種音段型。在76.5%的唱陣中個體只鳴唱一首歌曲型，每首歌曲型有11.4±2.8種音段型，各歌曲型所包含的音段型種類大多不重疊。平均每隻個體的歌曲型曲目量有7.0±1.5首，而音段型曲目量則平均有81.2±13.7個。個體間鳴唱聲相似度與距離皆呈現顯著負相關，彼此距離較近的4隻個體具有相當高度的鳴唱聲分享，而另外距離較遠的2隻個體則與其它個體分享極少數的鳴唱聲，顯示區域之間有明顯的方言。推測本種雄鳥鳴唱聲在防禦領域上扮演重要的功能。Breeding biology and male song of Taiwan Whistling Thrush(Myophonus insularis) were studied at Shuding and Nangang, Taipei from 2011 to 2013. Combined data from 2006, 2008 and 2009 by previous studies, 226 nests from 36 nesting areas were identified. The clutch size was varied from 1 to 4 with size 3 most common (64.77%). The mean clutch size and brood size was 2.69±0.56 and 2.33±0.72 respectively. Clutch size was significantly higher in the middle period than that of early period. Breeding success among years(2008, 2009, 2011and 2012) were estimated by Mayfield method were 47.0%, 41.7%, 34.7% and 37.2%. Breeding success decreased through season with 43.7% in early, 35.4% in middle, and 26.11% in late period. Nest predation(63.44%) and hatching failure(21.51%) were major causes for breeding failure. Nests with easy accessibility by predators were less successful than those of safer nests. The main predator was suspected to be snakes. The laying date was negative correlated significantly with air temperature of the period between Mar.1 and Mar. 10. Also the colder the year the lower productivity were found among 3 years(2006, 2011and 2012). For 6 male songs, 4525 phrases from 213 bouts were recorded. Twenty three song types and 223 phrase types were identified. About 76.5 % bouts had only one song type. Each song type had 11.4±2.8 phrase types. Phrase types had little overlap between different song types. The mean song type of individual was 7.0±1.5, and the phrase type was 81.2±13.7. That song similarity was negative correlation with distance, showed dialect may exist in closed vicinity.