In my current research I study movement ecology of birds and other animals, and especially the phenotypic characteristics of endogenous migration programs and how animals have adapted to cope with long migrations. Part of this project is dedicated to study the migration phenotype of young birds, and especially the variation and functional characteristics of the endogenous migration program guiding solo-migrating birds on their first migration. Connecting biology and physics I also have a strong interest in research questions connecting biology and physics, more precisely in sensory ecology, leading to several studies on Viking navigation, evolution of zebra coat coloration and animal navigation using skylight polarization and the earth’s magnetic field. I find swifts and their mobile lifestyle most fascinating. In 2009 I started a continental-wide tracking project on common swifts (Apus apus), where I track the migration strategies, route choices and movement adaptations, including the 10-month non-stop flights, of common swifts from different parts of the European and Asian breeding range.