台灣中部中高海拔山區道路邊緣灰林鴞（Strix aluco）食性研究

The Diet of Tawny Owls (Strix aluco) Analyzed by Their Pellets on Roadsides in Mountain Areas of the Central Taiwan

2000-2005 年間，在台灣中部中高海拔山區道路邊緣總共蒐集了180 枚灰林鴞（Strix aluco）的食繭。食繭長5.87±1.40 cm，寬3.42±0.72 cm，深2.62±0.42 cm。食繭內共發現7 種哺乳類，包括台灣森鼠（Apodemus semotus）、黑腹絨鼠（Eothenomys melanogaster）、高山白腹鼠（Niviventerculturatus）、小麝鼩（Crocidura horsfieldi）、松鼠科（Sciuridae）、條紋松鼠（Tamiops maritimus）與小鼯鼠（Belomys pearsoni）。鳥類共記錄6 類群，包括山雀科（Paridae）、畫眉科（Timaliidae）、鶯科（Sylviidae）、燕雀目（Passeriformes）、鴞形目中的黃嘴角鴞（Otus spilocephalus）與鵂鶹（Glaucidiumbrodiei）、鷹屬（Accipiter sp.）猛禽等。180 枚食繭中共發現544 隻食餌動物，平均每枚食繭包含3.02±1.77 隻食餌動物。灰林鴞的食餌動物中，以台灣森鼠出現的比例最高（43.9%），其次為山雀科鳥類（25.4%）與高山白腹鼠（10.8%）。生物量以台灣森鼠提供的最高（35.1%），其次為高山白腹鼠（30.7%），此兩種在4 個季節間所占的生物量比例合計在60-74.2%間，為灰林鴞重要的食物來源。灰林鴞在春、冬季每枚食繭內的食餌數明顯多於夏、秋兩季（p<0.05）。比較不同季節間灰林鴞的食性組成可以看出夏、秋兩季食物組成以哺乳類為主，而春季與冬季鳥類的比例增加。 Pellets of tawny owls (Strix aluco) were collected on roadsides in the Central Mountain Range at elevations of 1,479m to 2,650m in the central Taiwan, 2000 and 2005. For 180 pellets collected, the sizes were 5.87±1.40 (mean±SE) cm in length, 3.42±0.72 cm in width, and 2.62±0.42 cm in depth. A total of 544 prey items were identified from the pellets at 3.02±1.77 per pellet. They were composed of seven taxa of mammals (Apodemus semotu, Eothenomys melanogaster, Niviventer culturatus, Crocidura horsfieldi, Sciuridae, Tamiops maritimus, Belomys pearsoni) and six taxa of birds (Paridae, Timaliidae, Sylviidae, Passeriformes, Strigiformes, Accipiter sp.). In terms of the number of the preys, Apodemus semotus was most abundant, composing 43.9% of the total, and then followed by Paridae (25.4%) and N. culturatus (10.8%). In terms of biomass, A. semotus contributed 35.1% and N. culturatus was 30.7%. These two species were the most important diet, contributing 60 to 74.2% of the total biomass of the preys in the pellets of the owl. The average number of prey items were 4.28±1.90 per pellet and 3.58±2.14 per pellet in spring and winter, significant higher than 2.48±1.41 and 2.40±1.38 in summer and fall (Tukey test, p＜0.05). The diet composition also differed among seasons; mammals were major food sources in summer and fall, while birds became more important in spring and winter.