福山試驗林繡眼畫眉巢位棲地生態之研究

Abstract

為了瞭解福山試驗林中繡眼畫眉（Alcippe morrisonia）的鳥巢型態、巢位及巢樹特徵、鳥巢內外溫差，並探討巢位與微棲地特徵是否影響生殖成功等問題，於2002及2003年的2月底至8月初在福山共尋獲71個當年新巢，除了進行巢位及微棲地特徵測量工作外，並於2003年成功地記錄了一個．鳥巢的內外溫度達24天。結果發現：這兩年的3到5月為主要生殖季節，其中又以4月上旬為生殖最高峰。鳥巢為小型的杯狀巢，巢口向上，由外而內依序分為聯繫層、外層及結構層三層，內襯層則不明顯；整個巢所使用的巢材種類相當繁多，主要包括苔蘚、樹葉、小樹根及真菌等。所利用的巢樹並不具專一性，無論是草本、灌木或喬木上均有發現過築巢的紀錄，但其中又以杜鵑和長梗紫麻最常被使用。71個鳥巢中共41個有生殖紀錄，其中有19個巢成功22個巢失敗，掠食是造成生殖失敗的最主要原因，其次則為暴雨及颱風對於鳥巢的毀壞，然而成功或失敗的．鳥巢在巢位及微棲地各項特徵比較上未有顯著差異。此外，鳥巢隱密度、微棲地中的潛在巢位數量多寡、築巢地點離人為活動遠近等也都不影響鳥巢被掠食的情形。根據巢內外溫度記錄實驗得到的結果顯示，巢內每天的日夜溫差變化幅度較巢外小，在孵卵的初期巢內溫度波動較大，不似末期之溫度較穩定。巢內溫度之提升，主要應靠親鳥的孵蛋或孵雛行為，推測鳥巢可能具有減緩巢內溫度下降速率之功用。

In order to understand the nesting ecology of Alcippe morrisonia at Fushan Experiment Forest, Taiwan, the morphology and composition of bird nests, characters of nest site, nest tree characters, and nest external and internal temperatures were described and measured. All these characters were further discussed in terms of reproductive success. I conducted this study from late February till early August in 2002 and 2003, respectively. Seventy one new nests were discovered during intensive search. The major breeding season started from March to May, and peaked during the first half of April. The nest was an open cup and the layers from exterior to interior were named as attachment, out layer and structure layer. The lining layer was not obvious. The material used for nests was very complex and comprised mainly of moss, leaf, rootlet and fungi. The selection of nest tree species was not specific. We could find nests on herbs, shrubs and trees, but the Rhododendron L. and Oreocnide pedunculata (Shirai) Masamune were the most common nest tree species. Out of 71 nests, 41 nests were recorded with eggs or nestling. Among them, 19 succeed and 22 failed to fledge. The primary cause of nest failure was nest predation, and the second cause was the inclement weather. Features of nest site and microhabitat do not have significant influence on nest fate, neither do the concealment of nest, the potential nest site in microhabitat and the distance to human activity. According to the monitored temperatures inside and outside of two nests, I found that the nest temperature was more stable than air temperature and the key factor for raising temperature was parent’s company inside nest. The bird nest could play a role of temperature insulation and slow down the falling speed of temperature when parents left nests.