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

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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.