Selection across the annual cycle: examining movement, colour, and behaviour

每年，数十亿只候鸟在繁殖地和越冬地之间飞行数千公里，它们一生中的大部分时间都远离加拿大的繁殖地。尽管如此，大多数研究都集中在相对较短的繁殖季节。然而，为了理解影响这些鸟类生活的进化压力，我们需要涵盖整个年周期的研究方法。我的研究重点是了解全年发生的事件如何相互作用，以塑造生态，生活史和鸟类的进化。具体来说，我的目标是了解1)换羽（羽毛替换）策略的进化——在繁殖和迁徙方面，鸟类何时、何地以及如何换羽；2)在完成向南飞行之前，在墨西哥季风区停留换羽的几种北美西部候鸟采用的迁徙和换羽策略；3)全年发生的事件如何影响观赏羽毛颜色的进化。候鸟每年必须平衡三个能量密集的活动：繁殖、迁徙和换羽。虽然许多鸟类将这些事件分开，在繁殖后和迁徙前完成换羽，但其他鸟类已经进化出独特的策略，这些策略在不同物种之间差异很大-然而，我们对可能形成这些策略的生态或环境条件的理解有限。例如，在干旱的西部，夏末的食物资源相当有限，可能因此，许多物种在完成繁殖后就开始迁徙，但在完成迁徙之前，它们会在墨西哥西北部/美国西南部停留数周以换毛。这个时间与季风季节相吻合，季风季节将干燥的森林变成了郁郁葱葱的绿洲，有丰富的水果和昆虫——这是蜕皮的完美条件。鸟类在这一时期生长的羽毛不仅对飞行效率至关重要，而且对与竞争对手或潜在配偶交流信息也至关重要。然而，即使在这个地区，条件也会有很大的变化，通过跟踪鸟类的迁徙和换羽，我们可以了解换羽的位置和条件如何影响羽毛的颜色。的确，鸟类鲜艳的色彩吸引了科学家和公众的想象力。单个鸟类颜色的变化可以传达健康和状况的重要信息，雄鸟和雌鸟都用它来确定潜在配偶或竞争对手的质量。我的研究项目的最终目标是使用一种创新的技术（无线射频识别技术使鸟类饲养者分布在城市各处）在整个年度周期中跟踪单个鸟类，以探索色彩，城市景观中的运动，社会网络，行为优势和最终繁殖之间的联系。

Each year, billions of migratory birds travel thousands of kilometers between breeding and wintering grounds, spending most of their lives far from their Canadian breeding grounds. Despite this, most research has focused on the relatively short breeding season. Yet, to understand the evolutionary pressures shaping the lives of these birds, we need approaches that encompass research across the annual cycle. My research focuses on understanding how events occurring throughout the year interact to shape the ecology, life history, and evolution of birds. Specifically, my aim is to understand 1) the evolution of moult (feather replacement) strategies – when, where, and how birds moult with respect to breeding and migration, 2) migration and moult strategies employed by several species of western North American migratory birds that stopover to moult in the Mexican monsoon region before completing their southward journey, and 3) how events occurring throughout the year influence the evolution of ornamental plumage colouration. *** Migratory birds must balance three energetically intensive events each year: breeding, migration, and moult. While many birds separate these events in time, completing moult just after breeding and before migration, others have evolved unique strategies that vary extensively across species – yet, we have a limited understanding of the ecological or environmental conditions that may have shaped these strategies. For instance, in the arid West, food resources are quite limited in late summer and, likely as a result, many species begin migration just after the completion of breeding, but stop in Northwest Mexico/Southwest United States for several weeks to moult prior to completing their migration. This timing corresponds with the monsoon season, which transforms parched forests into a lush oasis with abundant fruit and insects – perfect conditions for moult. The feathers that birds grow during this period will be critical not just for efficient flight, but for communicating information to rivals or potential mates. Yet, even within this region, conditions can vary extensively and by tracking birds throughout migration and moult, we can ask how moult location and conditions influence feather colouration. ***Indeed, the brilliant colours of birds capture the imagination of scientists and the public alike. Variation in the colour of individual birds can convey important information on health and condition and is used by both males and females to ascertain the quality of potential mates or rivals. The final goal of my research program is to use an innovative technique (radio frequency identification enabled bird feeders distributed across a city) to track individual birds throughout the entire annual cycle to explore the connections between colouration, movement across an urban landscape, social networks, behavioural dominance, and ultimately reproduction.