福山試驗林繡眼畫眉性別差異及生殖生態學研究

Abstract

為探討繡眼畫眉雌雄鳥型態上的差異、生殖行為中雌雄扮演的角色分工、不同性別幼雛的成長以及族群中的性比，本研究自1994年1月至1999年12月，於福山試驗林進行繡眼畫眉（Alcippe morrisonia）繫放，上網之鳥經外型測量、拔羽或採血後釋回，所得樣本利用PCR法共鑑定328隻個體性別。另於1999年4月至5月（生殖季）觀察4巢孵卵及育幼行為。結果發現繡眼畫眉雄性成鳥的最大翼長較雌鳥長，體重小於雌鳥；幼鳥的最大翼長在生長初期雌雄沒有差異，體重也沒有差異；雄鳥的成鳥體重明顯小於幼鳥，雌鳥的成幼之間沒有差異。在繡眼畫眉體重的季節變異上，於9月份最重，12月最輕，雌雄鳥於非生殖季（8月至隔年2月）的體重變化趨勢相同；但生殖季初期（3月）雌鳥體重迅速增加，與雄鳥的變化不同。不論雌雄，繡眼畫眉的體重在一日中皆為早上最輕，傍晚最重。在生殖生態方面，繡眼畫眉雌雄共同參與白天孵卵、孵雛及餵食。白日孵雛的次數雌鳥大於雄鳥，夜晚孵卵及孵雛皆由雌鳥擔任。，整體而言雄鳥餵食頻率高於雌鳥，親鳥一次餵食僅攜帶一隻食蟲，雌雄攜帶的食蟲大小沒有差異。餵食頻率隨著幼雛日齡增長而增加，兩性變化趨勢無顯著差異。兩性幼雛離巢前的體重及附蹠長沒有顯著差別；雌雄雛鳥成長趨勢也沒有顯著差異。繡眼畫眉之性比不論在雛鳥、幼鳥及成鳥各階段，皆與1:1沒有顯著差異。

In order to understand the sexual morphological difference, the sex allocation of parental care, the growth rate, and the sex ratio of Grey-checked Fulvetta (Alicippe morrisonia), birds were captured and morphologically measured from January 1994 to December 1999 at Fushan Experimental Forest station. The germ feather and blood samples of 328 birds were collected from August 1997 to December 1999 and these birds were sexed by PCR method. I also observed the breeding behavior of 4 nests of Grey-checked Fulvetta from April 1999 to May 1999 during the breeding season. The morphological measurements were not significantly different between sexes except wing length and body mass. The wing length of adult and juvenile males was significantly longer than females'. The body mass of adult males was significantly lighter than adult females' and juvenile males'. The weight of the Grey-checked Fulvetta was the heaviest in September and the lightest in December. The seasonal change of body mass during non-breeding season was not significantly different between two sexes. During the early breeding season (March), the weight of females increased much more than males. The daily changes of weight were similar between two sexes, the lightest in the morning while the heaviest in the late afternoon. Both sexes shared the duties of incubation, brooding and feeding young, but with different weights. Females incubated fledging more often than males in daytime, and were totally responsible for night incubating. Parents fed young one worm each time. The size of the worm carried by males and females showed no significant difference. The feeding frequency of males was higher than females, and increased with the growing age of nestling for both sexes. The body mass and tarsus length of 8-days-old fledging and their growing patterns showed no significant difference between two sexes. No significant bias of sex ratio was detected at fledging, neither at juvenile and adult stages.