蘭嶼角鴞的移動與擴散

Movement and Dispersal of Lanyu Scops Owl (Otus elegans botelensis)

劉小如(Lucia Liu SEVERINGHAUS)

《台灣猛禽研究》 1期 (2003/09) Pp. 1-10

https://doi.org/10.30121/RRT.200309.0001

摘要

蘭嶼位於台灣東南方，面積僅45.7km^2。島上的蘭嶼角鴞（ Otus elegans botelensis）是居住於森林中的小型貓頭鷹，主要以昆蟲為食。亞成鳥獨立後會離開巢區向他處擴散，部分成鳥的繁殖地點也會每年變動。亞成鳥擴散的距離，或成鳥更換繁殖地點時的移動的距離，並沒有性別間的差異。研究區內所見角鴞隻數有很大的季節間變異，繁殖季時的密度極高。全年均停留在繁殖區的個體數很少，多是3－6歲的雄鳥。本研究利用霧網捕捉、環島調查、以及無線電追蹤等方法，檢視了三個可能解釋角鴞數量變動的假說。所得結果支持角鴞會在島內做季節間移動的假說，顯然許多繁殖烏會在繁殖季初期湧入繁殖區，在夏末遷移到非繁殖區度冬。

關鍵字

蘭嶼角鴞 ； 移動 ； 擴散

並列摘要

Lanyu is a subtropical island of 45.7 km^2 in area, lying southeast of Taiwan , The small and primarily insectivorous Lanyu Scops Owl (Otus elegans botelensìs) inhabits wooded areas on the island, Juveniles disperse at independence. Some adults also change their breeding locations from year to year. No sexual difference was found in the distances moved from natal site to a re-sighting site Numbers of owls seen in the study area showed large seasonal fluctuations, with high densities during the breeding season. Only a small number of adults remained in the breeding area year round, and these were mostly males 3-6 years old. Mist netting, monthly surveys, and radio-tracking were conducted to select among three hypotheses capable of explaining this fluctuation. Our results support the hypothesis that owls made seasonal movements between breeding and wintering locations on the island. Apparently, breeders crowd into suitable habitat before each breeding season, and disperse into wintering habitat at the end of summer.

並列關鍵字

Lanyu Scops Owl ； Otus elegans ； movement ； dispersal