Final Report Summary - STATEMIG (Fitness drivers in long-distance migrants: the interacting roles of physiology, social biology, ecological and physical environments)
Migratory animals face a number of challenges associated with finding the energy and nutrients essential to fuel their migration and the conditions the encounter en route. Our work shows that the essential nutrients (known as antioxidants) carried by individual birds is variable and that this variation has implications for survival. We also show that the conditions that migratory animals encounter can interact with the amount energy and nutrients that are carried and weather explains much of the year to year variation in reproductive success. We found that having a group of familiar flock mates (akin to “friends”) meant that birds could spend less time being aggressive with one another and less time searching for predators, which in turn should free up more time for foraging and that individuals show some flexibility in the way in which they are responding to weather conditions. These responses combine to influence the demography of the entire population yield important insights as to how species might respond to a changing climate. Finally, we also show that attaching devices to flying birds can affect survival and reproduction even when they comprise a small proportion of body weight.