臺灣灰鷽雌雄二型的百年錯誤

Nearly 100 Years of Confusion on the Sexual Dimorphism of Grey-headed Bullfinch (Pyrrhula erythaca owstoni)

Rothschild and Hartert於1907年描述並命名臺灣特有亞種的灰鷽（Pyrrhula erythaca owstoni）至今，國內外文獻，對其雌雄二型特徵的描述皆不盡相同。檢視19件灰鷽標本之後，雄鳥的背部、喉部、胸部及覆羽為鼠灰色，雌鳥為淡褐色。部分文獻對該特徵的描述則與事實相反，雄鳥的背部、喉部、胸部及覆羽錯註為淡褐色，雌鳥該部位則錯註為鼠灰色。灰鷽的最內側三級飛羽為藍黑色，其外緣並未具任何特殊的顏色。而部分文獻將灰鷽與台灣特有亞種的褐鷽（Pyrrhula nipalensis uchidai）混淆，錯誤描述灰鷽雄鳥的最內側三級飛羽外緣為鮮紅色，雌鳥為鮮黃色。有些圖鑑及工具書未檢視標本，而繪製此不存在的特徵。追查16件國內外報告及書籍之後，僅有2件文獻的描述完全正確，其餘皆有錯誤。在未追查原始命名文獻及檢視標本的情況下，該錯誤已存在一百年之久。在描述生物形態時，必須審慎地追根究柢，確實記錄自然現象。

Since Rothschild and Hartert first described Pyrrhula erythaca owstoni from Taiwan in 1907, its sexual dimorphism has been reported differently in literature, causing the confusion for nearly 100 years. Recently, we examined color characters of 19 specimens of P. e. owstoni and found their back, throat, chest and coverts were pale-gray for males while smoky-brown for females. To this character some books described it in the opposite way. We also found that the edges of the innermost tertial were blue-black without reddish or yellowish mark for both sexes. However, some books described the edges with reddish mark for males and yellowish mark for females. This disparity was apparently due to mistaken in species identification between P. e. owstoni and P. nipalensis uchidai. In some of the birds guide books and handbooks, P. e. owstoni was illustrated in the wrong sexual colors mentioned above. The authors apparently did not check the characters with those in the original description. We reviewed 16 literature sources and found that only 2 sources had the right descriptions.