Replaced feathers, degree of bill corrugation, and bill coloration in 19 Central American hummingbird species

We document molt extent; age-specific molt patterns, plumages, and percent of the bill with corrugations; the presence or absence of delayed plumage maturation and bill color changes in males of some species; and molt timing in the 19 resident hummingbird species of Belize. Molt strategies and rates of bill smoothing were similar to North American species, with all species showing limited to partial preformative molts, replacing only body feathers and some wing coverts and retaining all remiges and rectrices. Extent of bill corrugations reduced to ≤10% of bill length in all species by the time definitive cycle basic plumage is achieved. Males in sexually dichromatic species showed delayed maturation in plumage characteristics and/or bill coloration, and in two dichromatic species, some older females showed male-like plumage. Nine species representing multiple clades showed advanced timing to the second prebasic molt, indicating that this trait may be a proximal response to individuals not breeding during the first molt cycle. Species with advanced second prebasic molts replaced fewer wing coverts during the preformative molt than species with later molt timing.

Methods
Data was collected at 5 MoSI bird-banding stations in Belize, and also through analysis of photographs in the Cornell Laboratory of Ornithology's Macaulay Library.

本研究记录了伯利兹19种留居蜂鸟的换羽（molt）程度、年龄特异性换羽模式、羽衣（plumage）特征、喙部褶皱（bill corrugations）占喙长的比例；部分物种雄性个体的延迟羽衣成熟现象、喙色变化的有无，以及换羽时间节律。本研究涉及的换羽策略与喙部平滑速率与北美物种相似，所有物种均仅表现出有限的部分前成形换羽（preformative molt），仅替换体羽与部分翅覆羽（wing coverts），并保留全部飞羽（remiges）与尾羽（rectrices）。当所有物种达到终级周期基本羽衣（definitive cycle basic plumage）时，其喙部褶皱的覆盖范围均缩减至喙长的10%及以下。性二色性（sexual dichromatism）物种的雄性个体表现出羽衣特征和/或喙色的延迟成熟；在两种性二色性物种中，部分年长的雌性个体呈现出雄性样羽衣。涵盖多个演化支（clade）的9个物种表现出第二次基本换羽的时间提前现象，表明该特征可能是个体在第一次换羽周期未进行繁殖的近端响应。第二次基本换羽时间提前的物种，在前成形换羽期间替换的翅覆羽数量少于换羽时间较晚的物种。

研究方法
本研究的数据采集自伯利兹的5个MoSI鸟类环志站，同时通过分析康奈尔鸟类学实验室（Cornell Laboratory of Ornithology）麦考利图库（Macaulay Library）的馆藏照片完成。