繡眼畫眉（Alcippe morrisonia）生殖及鳥群生態之研究

Abstract

繡眼畫眉（Alcippe morrisonia）為福山試驗林鳥類群聚的最優勢種，於非生殖季時，常形成大型鳥群共同活動。本研究自1994年1月至1995年3月，於試驗林內之植物園區進行繡眼畫眉生殖及鳥群之研究。研究期間，除了進行捕捉標誌鳥隻外，並於生殖季時尋找鳥巢，進行持續性定點觀察，非生殖季時則利用追蹤觀察方式，研究鳥群的活動範圍、棲地利用、組成和數量變化等。 繡眼畫眉生殖季開始於4月中旬，持續至8月中旬，以5、6月為生殖高峰期。配對方式可能屬於一夫一妻制，雌雄親鳥皆會參與築巢、孵卵、孵雛、育幼、和照顧離巢幼鳥，但雌鳥與雄鳥個別的付出有巢間及階段性之差異。築巢需3至4天，每巢產3至4卵，蛋平均重量為2.3克，長寬為19.0×14.6公釐。雛鳥歷經12至14天孵化，之後親鳥仍會孵雛4至6天，於第9天離巢，再經過約40至65天後，即可獨立生活。育雛時期，隨著幼鳥的成長，親鳥餵食食物的長度及餵食頻度有逐漸增加的趨勢；所餵食的食物均為動物性，以鱗翅目及膜翅目的幼蟲為主（79.2％），直翅目次之（12.5％）。繡眼畫眉每窩卵的平均孵化率為75％，平均離巢率是84％，造成生殖失敗的因素是颱風、豪雨及人為影響。繡眼畫眉結群大小隨月份有所變動，在所追蹤的兩個主要鳥群，其結群數量由7月逐漸增加，達到最大的時間並不一致，一在8月（49隻），另一則於11月（62 隻），11月之後鳥群數量迅速下降至隔年3月時最小，各為27和37隻，兩群數量減少比率平均達41.9％。由標誌資料發現鳥群組成個體經歷一非生殖季之死亡率為49.3％，其中自然死亡率是33.8％，以1、2月死亡率最高。鳥群組成份子在進入8、9月以後即相當穩定。以方格法計算整個非生殖季鳥群活動之最小及最大活動範圍，在17.8至31.8公頃之間，日活動面積約4.3公頃。鳥群對最小活動範圍內不同棲地型態之利用並無顯著差異。鳥群活動範圍會與其他鳥群重疊，且無明顯的領域行為，重疊程度具區域性變異。

Grey-cheeked Fulvetta (Alcippe morrisonia) is the most abundant species in the avian fauna of Fu-Shan Forest. The breeding and flock ecology of Grey-checked Fulvetta were studied in Botanical Garden from January 1994 to March 1995. The breeding season began from mid-April and ended in mid-August with breeding peak in May-June. Mating system could be monogamous. Both parents shared the duties of building, incubation, brooding and feeding. However, the effort of female and male parents varied among nests or stages. Nest-building usually took 3-4 days. The clutch size was 3-4 per nest and each egg weighted 2.3 g when fresh. The incubation period was 12-14 days, and the young could fledge 9 days later after hatching. The young were fed for 40-65 days after fledgling. The feeding frequency and the size of the food positively correlated with the age of the young. The most common food type was the nymphs of the Lepidoptera and Hymenoptera (79.2%). During the non-breeding season, Grey-checked Fulvetta form large flocks. The largest sizes of two monitored flocks were 49 in August and 62 in November. The smallest size (27 and 37) occurred just before the breeding season. The averaging decreasing rate was 41.9%. The natural death rates of flock members were 33.8% majorly due to the cold weather in January and February. The compositions of the flocks became stable after August or September. Home ranges of the flocks were 17.8-31.8 ha according to grid cells counts. Flocks had no preference for different habitat within its home range. The home range of neighboring flocks overlapped with no obvious territory defense behaviors. The extent to which the overlappings were different between different areas.