Natal Versus Breeding Dispersal in Arctic Terns (Sterna paradisaea): A Banding Study From Denmark (1931-2005).

The dispersal of migratory birds is a crucial process that directly influences population viability, genetic connectivity and adaptive potential in changing environments. Using banding data spanning 75 years (1931-2005) for Arctic Terns (Sterna paradisaea) in Denmark, we identified 200 breeding dispersal and 890 natal dispersal events. We characterised their spatial and temporal patterns and compared the differences between natal and breeding dispersal. We found limited dispersal distances and restricted directional preferences, as well as a low trans-regional exchange rate during breeding dispersal. In contrast, natal dispersal exhibited longer distances, more diverse directional preferences and a higher frequency of cross-regional movement events. This study offers a valuable long-term dataset and a descriptive foundation for future research and conservation of these migratory birds.