Grant: Discovery Grants Program - Individual

Birds are highly mobile animals. In particular, migratory birds cross frontiers to breed, moult and winter at various locations over large geographic scales (300-8000 km). This very characteristic makes the study and conservation of migrating birds challenging. In the proposed research program, my aim is to describe the annual cycle of sea ducks and understand how the various biological phases are integrated chronologically and energetically in relation to breeding success. In the past 15 years, my work have been devoted to field work on breeding colonies, deployment of data loggers, development of software for data extraction, and experiments with captive and wild Common Eiders (Somateria mollissima, our model species). We found that daily energy expenditure (DEE) varied during the annual cycle with various ups and downs associated with productive costs occurring during post-hatching, moult and migration, despite strategies enabling energy minimisation like behavioural compensation and timing of important activities (moult) with favourable conditions (high water temperature). Experiments with captive ducks supported the notion that water temperature was used as an exogenous cue for the timing of moult. Moreover, we found that daily body temperature of wild ducks were highly correlated with photoperiod and water temperature for a full year suggesting that daylight was an important driver of metabolic activity. Therefore, I wish to pursue the general goal from former proposals together with new questions stemming from my lab. I will perform experiments with captive birds of different sub-species to determine the nature and the role of biological clocks in the timing of annual phases (biological seasons) and investigate the role of body mass and foraging effort in this respect, together with new deployments of data loggers on wild individuals from another population (sub-species) for comparative purposes. In the past six years, we also explored the migration strategy of eider ducks to discover that hyperthermia was occurring repeatedly during flights followed by regular stops to cool down, suggesting unexpected physiological and time costs to bird migration. Future work with imprinted and captive individuals is proposed in order to document the deleterious effects of flight-induced hyperthermia by measuring oxidative stress indicators under an experimental scheme. I believe the research proposed here to be highly innovative as it is based on a custom technology that allow the recording of highly relevant information of individuals in the wild together with experiments performed on captive birds aiming at identifying the underlying mechanisms shaping the annual cycle of birds.