Ben Sheldon, Department of Zoology, Oxford
Synchrony in space and time: matching timing across trophic levels as a key ecological driver of selection in great tits
The causes of variation in timing of breeding have been a key research question for evolutionary ecologists, particularly those working on birds, for decades. This interest stems from two sources: first, because timing of breeding seems frequently to be under strong selection in wild populations, creating the challenge of explaining how variation is maintained. Second, because timing of breeding has shown clear responses to changing climates, enabling in depth analyses of the causes of these changes. In this talk I will use long-term, and recent, data from the study of great tits in Wytham Woods to join these two perspectives together. I will argue that they key to understanding variation in timing of breeding in birds like the great tit lies in linking the birds' behaviour with the timing, or phenology, of other trophic levels, particularly deciduous trees, and crucially, doing this at the appropriate spatial scale. I will show that spatial heterogeneity in phenology of oak trees seems to be a key driver, and that spatial variation in tree health may also play an important role in explaining variation in responses to climate change in birds. There is tremendous scope for work on the evolutionary and ecological effects of synchrony between different trophic levels, both for understanding adaptation, but also for understanding effects of, and responses to, environmental change.