白尾鴝換羽膜式與年齡性別之判斷

Sexing, Aging and Molt Patterns of White-tailed Robin Cinclidium leucurum montium

野外年齡、性別的判別對鳥類生活史、行為生態及族群動態等生態研究是非常重要的。本研究利用「臺灣鳥類生產力與存活率監測（The Monitoring Avian Productivity and Survivorship program, Taiwan; MAPS Taiwan）」計畫及其相關活動於2008-2014年所蒐集之178隻白尾鴝（Cinclidium leucurum montium）的繫放資料，探討其換羽模式及年齡、性別判斷標準。結果顯示白尾鴝的換羽模式屬「複雜基礎策略（complex basic strategy）」，離巢幼鳥之「後幼鳥換羽（preformative molt）」屬「部分換羽（partial molt）」，二齡鳥於繁殖季後進行一次完全換羽（complete molt），之後每個換羽周期（一年）進行一次完全換羽。白尾鴝從離巢起即可以由羽色判斷性別。年齡則可以從羽色、頭骨氣室化程度、大覆羽幼鳥羽毛留存、尾長、飛羽及尾羽的色澤與形狀的輔助來分辨一齡、二齡與超過二齡。

Sex and age identification in the field are important to the studies of avian ecology, including life history, behavioral ecology, and population dynamics. We used banding data from 178 white-tailed robins (Cinclidium leucurum montium) collected in the Monitoring Avian Productivity and Survivorship, Taiwan (MAPS Taiwan) program and their relative banding activities from 2008 to 2014 to study molt patterns and criteria to determine their age and sex. The results showed that white-tailed robins followed complex basic molt strategy. In the first cycle, juveniles in their first basic plumage underwent a partial preformative molt within weeks after fledging. They entered a second prebasic molt after the breeding season in their second year, Their second and following prebasic molts were complete. Age can be reliably determined as hatch year, second year and after second year based on skull pneumatization, plumages, molt limits and the shape and condition of the great coverts, primaries and rectrices. Since their plumages are sexually dimorphic, individuals with blue in feathers are male. Otherwise, they are female.