Abstract
Climate-change leads to advancement in tree-phonology in temperate regions, and a subsequent advancement in insect-abundance. Most temperate breeding bird species are for their breeding success highly dependent on this peak in insect-abundance, and most, but not all, bird-species have advanced their egg-laying dates over the last decade. Migrant species might face an important constraint for a further advancement of their laving-dates, since climate changes may not occur on their wintering grounds. These birds may not have the right cues to start spring migration at the appropriate time when climate changes, and hence may arrive too late in their breeding areas to profit from the food-abundance in spring. This is a possible reason why many passerines that winter in tropical regions have shown a decline over the last decades in both the Old and the New world temperate regions. The aim of this project is to understand whether migrant species are indeed constrained by their migratory behaviour in adjusting their laving date to climate changes at temperate regions. We aim to study both genetic and phenotypic effects determining arrival dates, and how selection favours early arriving birds. The outcome of these effects will be used to model population dynamics and hence the likelihood of decline to extinction. The model species used in this project is the Pied Flycatcher. This migrant winters in tropical Africa, and has shown an advancement of egg-laying over the last 20 years, but no advancement in spring arrival date. In the last years the birds did started egg laying almost directly after arrival and in the next years we expect that these birds face the problem that they arrive too late to have a high reproductive success.
Netherlands