Migratory species often spend the non-breeding season in areas that differ in both distance from the breeding grounds and habitat quality, which can cause a segregation of the population. In sexually dimorphic species, differential energetic requirements and foraging strategies of each sex can lead to the use of different non-breeding grounds. However, because migratory birds use very distant and often hard to access habitats, it is often difficult to systematically assess a population's adult sex ratio (ASR) over time and across sites to get insights into sexual segregation. Here we study a long-distance migratory shorebird, the Hudsonian Godwit Limosa haemastica, to explore the ASR in two separated bays at Chiloé Archipelago (41°S, Chile) and evaluate potential segregation of the sexes within this population during the non-breeding season. Using a molecular approach, we developed a standardised criterion to accurately sex the individuals based on their bill length. With this criterion we were able to sex 92% of the sample (n = 265), with the remaining corresponding to birds in the overlapping range of bill lengths that needs to be sexed molecularly. We found that this godwit population, which breeds in Alaska, does not present a large-scale sexual segregation between non-breeding sites but is overall male-biased (ASR = 0.59). Interestingly however, there were significant differences in ASR between bays that were maintained throughout three consecutive non-breeding seasons. Further studies are needed to estimate potential consequences of these local differences in ASR on the population dynamics of this interhemispheric migratory species.

迁徙物种通常在距繁殖地距离和生境质量都不同的区域度过非繁殖季节，这可能导致种群隔离。在有性双态物种中，每个性别的不同能量需求和觅食策略可能导致使用不同的非繁殖场。但是，由于候鸟使用的距离非常遥远，而且通常很难进入栖息地，因此通常很难系统地评估一段时间内和跨地点的人口成年性别比（ASR），以了解性别隔离。在这里，我们研究了一种长距离迁徙的水鸟，哈德逊戈德威特Limosa haemastica，以在ChiloéArchipelago（智利，41°S）的两个独立海湾中探索ASR，并评估非繁殖季节该种群中性别的潜在隔离。我们使用分子方法，开发了一种标准化的标准，可以根据个人的账单长度准确地对他们进行性别区分。按照这个标准，我们能够对92％的样本进行性别分析（n = 265），其余的对应于在票据长度重叠范围内需要进行分子性别分析的鸟类。我们发现，这种在阿拉斯加繁殖的黑线种群不会在非繁殖场所之间出现大规模的性别隔离，但总体上是男性偏见的（ASR = 0.59）。然而，有趣的是，在连续三个非育种季节中维持的海湾之间，ASR存在显着差异。