台灣熊鷹的冠羽多型性初探

台灣的熊鷹（Nisaetus nipalensis）屬於指名亞種（N. n. nipalensis），過去都認為其頭冠型態是短冠型，但近年來卻陸續發現具有長冠羽的個體。為了瞭解台灣熊鷹的冠羽型態變異，我們經由巢位觀察、捕捉繫放、徵求鳥友拍攝的野外照片、檢視博物館的標本以及動物園和救傷中心圈養的個體，共計辨認58隻熊鷹的頭冠型態。結果顯示大多數的熊鷹是短冠型，但有少數個體（在台灣南部的比例是13.3%）具有較長的冠羽，此長短冠的型態差異並非換羽所造成，初步也認為與性別和年齡無關，但換羽可能會導致長冠型個體的比例被低估。長冠型熊鷹的冠羽長度和數量並不一致，顯示台灣的熊鷹頭冠可能具有多型性，此外也發現一個親代和子代的頭冠型態不同的案例。台灣的熊鷹同時存在長、短冠個體的原因仍不明，有待進一步研究。目前多數圖鑑以長頭冠代表熊鷹指名亞種、或以短頭冠代表台灣的熊鷹都不適當，應考慮修正。

關鍵字

熊鷹；長冠型；分布；形態多型性；台灣

並列摘要

Mountain Hawk-Eagle (Nisaetus nipalensis) in Taiwan was sorted to nominate subspecies, N. n. nipalensis. This subspecies was generally thought to have monomorphic short crests in Taiwan. However, in the past decades, there have been several long-crested individuals discovered in Taiwan. To understand the pattern of crest type of Mountain Hawk-Eagle in Taiwan, we identified crest type from 58 individuals through nest observation, capture, examination of field photos from bird watchers, specimens, and rescue cases. The result indicated that short-crested type dominated, while long-crested type occupied only 13.3% of our samples in southern Taiwan. Crest types were not relevant to moult, age, or sex. However, moulting may cause underestimation on the percentage of long-crested type. Long-crested individuals had crests that varied in the number of crest feathers and in crest length. This different pattern may indicate crest polymorphism in Mountain Hawk-Eagle in Taiwan. In one case, crest types were different between a pair of short-crested parents and their long-crested young. The reason of coexistence with different crest types Mountain Hawk-Eagle in Taiwan needs further study. We suggest that using crest types to distinguish among nominate and the other subspecies, as most field guides illustrate, is inappropriate.

並列關鍵字

Mountain Hawk-Eagle ； long-crest type ； distribution ； morphological polymorphism ； Taiwan

國際替代計量

台灣熊鷹的冠羽多型性初探

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